6Th Gen Getting ~30Mpg...?

My 2004 is running fine and is all factory (no exhaust system changes, factory air filter, everything as it should be) yet with mostly commuting miles I'm getting ~30mpg which is lower than I used to get on my former 2004. I was having the flat spot issue and for a time had O2 eliminators on the sensors but didn't find any dramatic improvement so I removed them. I also ran some Seafoam through the system a few months ago over a few tanks of gas (the PO had her sitting for a few years) in case it was some crud buildup causing the flat spot but again there was no miraculous change.

I'm not anxious to get into a quest for some gremlin, but I would like to be seeing closer to 40mpg. Any ideas? Throttle body synch worth trying?

How's your engine temperature? Maybe the thermostat is stuck open.

Maybe check out this thread...

http://www.vfrdiscussion.com/forum/index.php/topic/76673-poor-fuel-economy-2009-vfr-800/

sudo

How's your engine temperature? Maybe the thermostat is stuck open.

I don't believe so...the fan cycles on/off normally. Is that a valid sign that it's working ok?

Duc2V4

Maybe check out this thread...

http://www.vfrdiscussion.com/forum/index.php/topic/76673-poor-fuel-economy-2009-vfr-800/

Just gave it a read through...and now I'm indeed wondering about the thermostat. What's the best way to check it?

The bike should get to 170F within the first 2-3 miles of a ride and then maintain temperature. It can be easily diagnosed when its chilly outside.

When I had this issue, I was running at 158F to 160F after 30 min of riding when ambient temperature was 60F.

FM1

The bike should get to 170F within the first 2-3 miles of a ride and then maintain temperature. It can be easily diagnosed when its chilly outside.

When I had this issue, I was running at 158F to 160F after 30 min of riding when ambient temperature was 60F.

Well I rode into work today and it's relatively quiet....maybe I can sneak out a little early to check the bike out. I did notice this morning gassing up that the fan was coming on as I would expect (~215F) and I did not notice it running particularly cool....but I was not looking for it. Thanks for the input.

I would also suggest testing it out when its less than 60F and NOT in stop and go traffic.

I had this issue for a year but didn't notice it until this winter..Fresno is so hot most of the year that you dont notice a stuck open thermostat.

Ok, so...~45 mile jaunt in the hills on the "way home" :goofy: today to try to suss this out.

In light traffic/stoplights (~60F, high temp seen was ~190-200F)

In the hills (~50-55F, high temp seen was in ~170F)

Highway run on the way home (~55-60F, mid-170s to mid-180s as ambient temp rose)

Based on FM1's comments above I think I may be ok in regards to the thermostat working correctly - agreed?

Your thermostat seems to be fine. Before you go through starter valve sync I would suggest checking your idle speed. You have to check it once you bike is warmed up --around 170F.

Adjust it low enough so the bike doesnt stall at idle. Mine is set at around 900-1000 rpm.

For syncing you will need a multi meter (since you dont have a PC) with rpm and manometer.....if you dont have these, you are looking at an investment 150-200 bucks.

Below are helpful links;

http://www.vfrdiscussion.com/forum/index.php/topic/33-starter-valve-syncronization-vtec/

I have my idle set to around 1.1-1.2k IIRC. I have a multimeter, but not as nice as that shown...and frankly I don't think I have the wrench spinning chops to pull off that job. :comp13:

Thank you VERY much for your input. Years ago I paid a tech to do the synch and it wasn't unreasonably costly, I'm going to call around to a shop I know and trust and see what it might set me back to have them give it a go.

I really appreciate the help!

You should not have to do the sync again. Check all the usual stuff first, Air box for oil from over filling crank case with oil , Air filter, plugs try some SeaFoam, Charging system , If you do the sync and its out again, MAKE sure to check starter valve that is non adjustable for a loose screw. My primary starter valve that was non adjustable had loosen up and was driving me crazy after the four attempt I reach in small needle nose pliers and the dam thing turned it was loose from the factory. Set it and crimp it so it could never turn again set the starter valves have not touch them in 50,000 miles.

Switchblade

You should not have to do the sync again. Check all the usual stuff first, Air box for oil from over filling crank case with oil , Air filter, plugs try some SeaFoam, Charging system , If you do the sync and its out again, MAKE sure to check starter valve that is non adjustable for a loose screw. My primary starter valve that was non adjustable had loosen up and was driving me crazy after the four attempt I reach in small needle nose pliers and the dam thing turned it was loose from the factory. Set it and crimp it so it could never turn again set the starter valves have not touch them in 50,000 miles.

Sorry man, I was not clear. I did the synch previously on another bike, not this one. To my knowledge it has never been done on this bike. Thanks!

Deafinitely do it .

Ok so...valve synch done, fuel pressure regulator checked...ok, fuel system ok, O2 sensors ok...but the bike is indeed running rich. After a chat with Havagan and the shop owner the next checks are the throttle position sensor and he was going to run the exhaust gas check again to try to narrow it down to which cylinder(s) are running rich if not all of them...but he seemed a bit stumped. None of the usual mechanical causes for rich running appear - it's all factory so not a power commander glitch or such and it's rich across the RPM range.

Anyone that has a miracle vision on what's up is welcome to reply.

:goofy:

Hmm maybe a faulty injector ...

And thanks for the update !!!!

Multiple dyno runs, checks out fine but still 10 - 12:1 FAR across the ROM range. Shop owner totally stumped as O2 sensors seem ok, fuel pressure ok, thermostat ok etc etc.

At this point he's suggesting a Power Commander since it costs the same as two Honda O2 sensors (and less than an ECU). Anyone have a tip on a good deal? Anyone want to sell theirs?

hey Duc2V4...what are you getting mpg-wise? I've been at a consistent 32 mpg since I bought this thing, and I've done the math on every single tank for over a year now. I never even thought it could be any better.

I've got Staintunes, PC5, no flapper valve, no PAIR valve...

wgregt

hey Duc2V4...what are you getting mpg-wise? I've been at a consistent 32 mpg since I bought this thing, and I've done the math on every single tank for over a year now. I never even thought it could be any better.

I've got Staintunes, PC5, no flapper valve, no PAIR valve...

I ended up doing a flush/fill on the "motor" fluids (Oil and coolant), changed the spark plugs, replaced the snorkel, replaced the flapper, loaded one of the PCV maps on the forum, started using 87 octane and my mileage went up to 190-200 per tank. Obviously, when "sporting it", it's the lesser mileage but on the average it went up. FYI, I am using Rotella T6, Engine ice coolant but I'll have to look up what map I am using.

I've always used the 87 octane my whole life in everything. I'm getting about 170 a tank, and you are in the 190-200 range. And you removed the snorkel and flapper, then put them back on?

I have no idea what map I have on the PC5. No idea how to check or change it either. I'm assuming it isn't Mac based, so I'm at a loss probably.

Al,

I would check the hot wax unit. Its a PITA very much like a thermostat replacement but there are some ports in the casting that can become obstructed with sediment over time. This can interfere with its travel distance. You might be running like with a partially active choke. Wouldn't affect running temps but plays heck with the mileage.

I don't believe that's been checked. Where/what is the hot wax unit? Is it similar to the airbox temp sensor? That's what the guy was going to check.

Question: if the bike is idling normally (it is) would that still be a factor?

Probably not, did the bike ever run right ?

Al,

The hot wax unit is a small, self contained unit mounted down between the throttle bodies. It is basically an automatic choke. It has an actuating rod that extends or contracts depending on its temperature, as a function of the coolant which surrounds the cylinder containing the wax. When cold the arm movement works on a plate on the starter valve assembly and as the wax melts changing the plates position it changes the fuel enrichment to normal levels. Thought maybe it is not traveling its full range such that while it might appear to be normal there may still be a little choke being applied. I had one of mine completely apart last year. You can check the unit using the hot water tap. Response is almost instant.

Ernie

PS1. I could be totally off base on this because all my experience is on 5th gens, specifically the 2000 models because this feature was not incorporated on the 98 and 99s. Just assumed it was carried over to the 6th gens.

PS2. OK, I went back and watched the video of FM1 and the whole area between the throttle bodies is totally different than what I am used to. This whole Hot Wax Unit thing may be a wild goose chase. Sorry Al.

Ernie,

No apology needed, I really appreciate the help. The guy was indeed going to check the idle thing, based on your comments it sounds like the same thing - the idle/warmup adjuster that's not a choke but kinda is. ;)

Switchblade

Probably not, did the bike ever run right ?

The bike actually starts and runs like a champ - she's just a bit too thirsty for fuel.

Al,

I checked with my youngest who works at the Honda shop in Tulsa, and he says the VTECs do have a hot wax unit. So, it might bear worth looking into. It wouldn't have to be off very much to cause an issue. I reread your replies about running temps and they sound a little bit suspicious to me. My guess is that you don't have the temp extremes there that I see here so it is harder to diagnose but IIRC on a day where ambient air temps are in the 70s cruising gives me engine temp of 185. Stop and go will elevate until the fans kick on around 215-218. But even when really cold it maintains at no less than 175. I think the thermostats are rated at 185.

I beginning to think your catalytic converter is clogged, if its been running this rich for awhile it could be almost clogged ..

Switchblade

I beginning to think your catalytic converter is clogged, if its been running this rich for awhile it could be almost clogged ..

The bike doesn't quite have 7k miles on it, so I would hope that's unlikely. Shop is closed on Monday so I'm shopping Power Commanders and waiting to see if they find something with the wax unit.

PorradaVFR

Switchblade

I beginning to think your catalytic converter is clogged, if its been running this rich for awhile it could be almost clogged ..

The bike doesn't quite have 7k miles on it, so I would hope that's unlikely. Shop is closed on Monday so I'm shopping Power Commanders and waiting to see if they find something with the wax unit.

I hope the PC makes it better and not worse .

The CAT won't ever clog, unless your engine tears itself apart. it might not work as intended if fed overly rich mixture for too long, but remember it gets this everyday when its cold !

Hot wax unit is a good probability. The other thing to check is did you reconnect the O2 sensors correctly after you got rid of the O2 eliminators ? If not connected or not correctly connected, then the ECU goes into get you home mode, which is like a system failure mode & runs very rich. You should have an EFi warning light, check it lights with ignition on but engine stopped. Should clear at engine start under normal circumstances, but the bulb can blow if left on for too long !

Mohawk

The CAT won't ever clog, unless your engine tears itself apart. it might not work as intended if fed overly rich mixture for too long, but remember it gets this everyday when its cold !

Hot wax unit is a good probability. The other thing to check is did you reconnect the O2 sensors correctly after you got rid of the O2 eliminators ? If not connected or not correctly connected, then the ECU goes into get you home mode, which is like a system failure mode & runs very rich. You should have an EFi warning light, check it lights with ignition on but engine stopped. Should clear at engine start under normal circumstances, but the bulb can blow if left on for too long !

I'm hoping the hot wax thing pans out as I'm not really anxious to spend $300 on a PC if it's not really needed. We did check the O2 sensors (repeatedly) and they were correctly connected and re-connected just to be sure. The ECU does throw a code when they're not plugged in so it does not appear that it's "missing" anything (like a bad O2 sensor). I'm trying to rationalize in advance that I was already irritated by the slight flat spot ~5k RPM and with the hope that a PC will bring the fuel economy up to closer to 40mpg and (eventually) make financial sense.

Do folks with PCs have any reason to avoid them?

Al,

I think most folks adding a PC do so to maximize power output and or tune to an aftermarket exhaust add on, but I guess you could also use one to lean out the mixtures, ignoring the HP numbers. My experience with my 5th gens indicates a slightly lower mpg in exchange for the increase in power. Either way to get the full benefit I feel you need to dyno tune them. But, that's just my opinion. I took one of mine off and saw a noticeable improvement in economy and very little , if any, loss in performance. Hope you get it sorted out to your satisfaction!

Ernie

Hot wax unit would just increase idle or not work at all . No affect on anything else. And we had a member here who had a clog cat and replacing it finally solve has problems BUT his also did not perform very well.

Wax unit only works on the starter valves at idle only and when cold , as soon as you twist the throttle the starter valves are by passed by the butterfly valves.

If you still think its the hot wax unit pull the air box and back the adjuster nut on the wax unit all the back.

http://www.youtube.com/watch?v=k4oVVbzTvVo#t=0

Whats the temp in Santa Clara today ?

Switchblade

Wax unit only works on the starter valves at idle only and when cold , as soon as you twist the throttle the starter valves are by passed by the butterfly valves.

Hmmm....then that might be a pointless exercise entirely, the bike is running rich WOT and warm. Argh!

Switchblade

If you still think its the hot wax unit pull the air box and back the adjuster nut on the wax unit all the back.

http://www.youtube.com/watch?v=k4oVVbzTvVo#t=0

Whats the temp in Santa Clara today ?

Bike is still at the shop and they're closed today. I'm waiting to hear what his last efforts came up with from Saturday and if we're still flailing I'll look to order a PC. The other option, as noted earlier, was to presume the O2 sensors are bad and replace them...but that costs the same as a PC+ eliminators which ideally would fix this ANY maybe improve performance a tad to boot. I dunno, I'm kind of feeling like I'm chasing a gremlin at this point with no hard lead on what to check beyond what's been done.

Did you clean the O2 sensor's after you remove the resistors ? If not there not working and if you do clean them pull both battery leads and let the bike sit for 10 15 minutes and then reconnect the battery . At least pull and inspect them .

After reading through this thread, it makes me think that maybe I should look into a few things on my bike. I finally got to run a full tank through it since I got it home last month and she only pulled 34mpg out of the tank. My bike is stock except for the few free mods.

Switchblade

Did you clean the O2 sensor's after you remove the resistors ? If not there not working and if you do clean them pull both battery leads and let the bike sit for 10 15 minutes and then reconnect the battery . At least pull and inspect them .

I ran the resistor's on my for a couple of weeks, it did run better but did not like the gas mileage around 34 35 mpg never 30 mpg.

But when i went back i cleaned mine with Seafoam and gas and wire brush . Mine were completely covered in carbon black soot .

Hmmm...you're saying dirty O2 sensors might be a problem? They were out and dirty - not crusted up or sooty, but definitely not shiny metal. That is intriguing - what would be expected at 7k miles? I would say they look like the inside of an exhaust more or less.

Would dirty sensors throw up a code?

No Code for dirty sensors, as I discovered playing around with my 5th gen, the O2 eliminators (resistor in my case) is only required on one O2 cable, the ECU is happy so long as it see heater power draw on one sensor. the resistors are there just to simulate power draw to the sensor heater. If the ECU then does not get a reading from the sensor, it just assumes worst case scenario & starts dumping a very rich mixture in.

When I had the dyno tune done for my PC I left the O2 sensors in & was getting circa 35mpg (UK gallon = 4.5L / US gallon = 3.8L) with the eliminators in place fuel consumption was down to 30mpg :( Needless to say I put the sensors back in. But my next tune will have them removed completely.

Mohawk

No Code for dirty sensors, as I discovered playing around with my 5th gen, the O2 eliminators (resistor in my case) is only required on one O2 cable, the ECU is happy so long as it see heater power draw on one sensor. the resistors are there just to simulate power draw to the sensor heater. If the ECU then does not get a reading from the sensor, it just assumes worst case scenario & starts dumping a very rich mixture in.

When I had the dyno tune done for my PC I left the O2 sensors in & was getting circa 35mpg (UK gallon = 4.5L / US gallon = 3.8L) with the eliminators in place fuel consumption was down to 30mpg :( Needless to say I put the sensors back in. But my next tune will have them removed completely.

Makes sense !!! I would at least try it before buying a PC ..

Mohawk

No Code for dirty sensors, as I discovered playing around with my 5th gen, the O2 eliminators (resistor in my case) is only required on one O2 cable, the ECU is happy so long as it see heater power draw on one sensor. the resistors are there just to simulate power draw to the sensor heater. If the ECU then does not get a reading from the sensor, it just assumes worst case scenario & starts dumping a very rich mixture in.

When I had the dyno tune done for my PC I left the O2 sensors in & was getting circa 35mpg (UK gallon = 4.5L / US gallon = 3.8L) with the eliminators in place fuel consumption was down to 30mpg :( Needless to say I put the sensors back in. But my next tune will have them removed completely.

I don't understand...my understanding was that you HAD to eliminate the O2 sensors when using a PC as otherwise they would effectively countermand it, or you would get an error code. How did you have them co-existing?

PorradaVFR

Mohawk

No Code for dirty sensors, as I discovered playing around with my 5th gen, the O2 eliminators (resistor in my case) is only required on one O2 cable, the ECU is happy so long as it see heater power draw on one sensor. the resistors are there just to simulate power draw to the sensor heater. If the ECU then does not get a reading from the sensor, it just assumes worst case scenario & starts dumping a very rich mixture in.

When I had the dyno tune done for my PC I left the O2 sensors in & was getting circa 35mpg (UK gallon = 4.5L / US gallon = 3.8L) with the eliminators in place fuel consumption was down to 30mpg :( Needless to say I put the sensors back in. But my next tune will have them removed completely.

I don't understand...my understanding was that you HAD to eliminate the O2 sensors when using a PC as otherwise they would effectively countermand it, or you would get an error code. How did you have them co-existing?

Me too but they do have the auto tune PC which I think you install a wide band O2 sensors in place of the old O2 sensors.

Switchblade

PorradaVFR

Mohawk

No Code for dirty sensors, as I discovered playing around with my 5th gen, the O2 eliminators (resistor in my case) is only required on one O2 cable, the ECU is happy so long as it see heater power draw on one sensor. the resistors are there just to simulate power draw to the sensor heater. If the ECU then does not get a reading from the sensor, it just assumes worst case scenario & starts dumping a very rich mixture in.

When I had the dyno tune done for my PC I left the O2 sensors in & was getting circa 35mpg (UK gallon = 4.5L / US gallon = 3.8L) with the eliminators in place fuel consumption was down to 30mpg :( Needless to say I put the sensors back in. But my next tune will have them removed completely.

I don't understand...my understanding was that you HAD to eliminate the O2 sensors when using a PC as otherwise they would effectively countermand it, or you would get an error code. How did you have them co-existing?

Me too but they do have the auto tune PC which I think you install a wide band O2 sensors in place of the old O2 sensors.

Ahh...yeah, that's available but substantially more expensive. I'd opt for the $20 eliminators (or hell, put the resistors back in).

The best mileage I ever got was 36 mpg with resisitors ..

Hmmm, my bike gets terrible mileage when commuting (like 30-32 mpg) but i put that down to long idle times at lights. I will have to try a full tank ride to see what it does when not commuting.

You think stop lights have something to do with this? That seems really negligible to me. If it helps, I use mine solely for commuting, never stop basically (first at every light/stopsign here in SoCal and first to leave every light/stop sign, and I split lanes the whole way = as close to non-stop as you can get, really) and I still get 30-32 MPG.

wgregt

You think stop lights have something to do with this? That seems really negligible to me. If it helps, I use mine solely for commuting, never stop basically (first at every light/stopsign here in SoCal and first to leave every light/stop sign, and I split lanes the whole way = as close to non-stop as you can get, really) and I still get 30-32 MPG.

My suspicions were raised because I've had other VFRs and they all had better mileage and the dyno results confirm that she is indeed running materially rich...still I'm getting close to either popping in a Power Commander to lean her out or frankly just accepting that Dusty's a thirsty girl - the shop has done right by me chasing this gremlin down but a few hundred in all I know is that she's running rich with no mechanical issue found.

At this point it's good money after bad chasing the mystery and overall the verdict on PC seems pretty positive. I'll likely just opt for that route and get back to riding.

I have the Power Commander 5 on mine (along with Staintunes.) Didn't change my MPG at all.

I went on a long ride this weekend cruising at 80-85 most of the way. That's about 5.5-6k rpms in 6th gear. On the way back there was some, let's say, more spirited riding. At the end of the ~190 mile trip my tank was empty and I calculated just over 40mpg. I have a 2Bros. slip on and no power commander.

Ok guys, got and scanned the dyno info. Does this say anything obvious?

[image: post-2418-0-60670300-1394856450.jpg]

Does that say 75 HP max???!!! Should be 100+.

Tells me you have a problem ....

Hi Al,

My bike has about 60HP based on following you the other day and that dyno showing yours at 75HP :wacko:

I guess we really get screwed in California when it comes to handing out HP :goofy:

Duc2V4 back at post #3 of this thread called out a another interesting thread...in post #2 of that thread from Chris L noted that Pair Reed valves can get crusty and let fuel leek back into the air box. Yours had sat for a few years so maybe they're messed up. Sticking in a Toys R US marble in the hose leading to each pair valve is not that hard (I was even able to do it) and is easily reversed.

You noted separately that the dyno showed your rich condition went away with the air box open with no air filter...not sure what this indicates but maybe the VFR scientists can read meaning from it.

Also, I found my ECU worked better after blasting the pins of the 2 main connector terminals with contact cleaner/lubricant from home depot. It even masked a couple of messed up wires for about 6 months.

Havagan

Does that say 75 HP max???!!! Should be 100+.

I was curious about that too...what I'd love would be a dyno chart of the same vintage to compare. The ones I found showed far flatter FAR across the range...and leaner too (12+). I'll also check the manual to find the ECU leads and inspect them. Thanks guys.

Hi Al,

In this thread

http://www.vfrdiscussion.com/forum/index.php/topic/76673-poor-fuel-economy-2009-vfr-800/page-2

Chris L says:

One thing that tends to affect older, higher mileage bikes is crud building up on the PAIR valves. The PAIR valves are designed to let air from the airbox into the exhaust manifold to burn unburnt petrol, and they are one way, metal reed valves. Trouble is that over time & distance, crud builds up, the valves leak backwards, and the exhaust gasses can get into the airbox, screwing up the mixture and generally dropping the mileage figures quite drastically.

My theory is

that when your bikes rich fuel condition corrected with the air box cover and filter removed , it may have been attributable to it counter acting the "backwards pair valve leak" of exhaust gasses into the air box that Chris mentioned.

Al -- did I mention that I did the de-PAIR on my bike when I had the fueling fixed? Pulling the PAIR stuff can't hurt.

What I find interesting is the temporary spike in the AFR to near normal about where VTEC is engaged. That might be explained by the extra air coming in to each cylinder before the ECU can change the AFR back to what it thinks is correct. I couldn't find anything in the thread about having verified that the MAP sensor is operating properly. Can't say for sure, but If out of spec it might account for the AFR curve from the dyno. There's a test routine in the troubleshooting section of chapter 5 (fuel system) of the FSM for it. You'd need an ohm meter and a hand operated vacuum pump but it's easy to get to by lifting the tank. It would also be good while in there to check that all vacuum hoses are in good condition and properly connected.

I spoke to my Honda tech this weekend about my low-ish MPG while I was getting new tires balanced. His first thought was the fuel pressure regulator. I brought up a bad thermostat, and he said "yeah...that COULD do it, but you'd notice your temp not getting up to normal (210 F or so) temps as well, and if that's not happening, I'd say the thermostat is OK."

A couple of other techs chimed in with it most likely being a sensor of some sort that's bad, or a series of bad sensors (fuel, MAP, etc) that together might bring me up a few MPGs, but their thoughts were if only any one sensor is bad it would only be losing me 1-3 MPG at the most. I brought up that a few folks here get/used to get 200 miles per tank when the bike was new, and some are even now down to 160-ish a tank on stock bikes (which mine is not.) I told him my best was exactly 176 per tank, at which point I was pushing it two miles to the gas station (not a pleasant story.)

He said frequently folks don't fill the tank to the very top as well. Specs show the tank holds 5.81 gallons when dry. I'll have to check, but I don't think I've been putting that much in. I'm really tempted to carry my 1 gallon plastic gas tank in my topcase when I get close, run it dry, pour in the one gallon, and see if I can put 4.81 gallons more on top of it.

even bikes with stuck open thermos are getting to 210 degrees, but they normally wont hold above 170 on open road for long above 40 degree temps. Another test is to cold start the bike, wait till you see the first water temp read, and take off, should be above 150 degree and climbing by one mile. if its taking a lot longer than that, its suspect in operation, some are not stuck fully open but half open, this would be very confusing. another key is falling below 159 degree on open road in sub freezing temps.

I can only vouch the 6th gen will hold a little more than 5.3 gallon, there may be 2 cups of fuel left more than that. That's about as close as you'd want to get.

several years ago, when my bike was running hard compound tires, and before the U.S fuel change, Id see mid to high 40's on open road travel in the deep very hot summer(best was about 47 mpg and included post 100 mph, the same conditions with softer compound tires and present day fuel, about 43 mpg at best on open road. Riding mostly 40 mph narrow back roads, along with full flogging zero to post 100mph I see around 38 mpg on average.

So....they only way to check or change a map on a PC5 is with a PC laptop?? So as a Mac-only guy, now I need to buy a PC to see what map I have currently (I got it used so I have no idea) or to change it??!!

So the latest on this was I finally pinged my local dealership with whom I've been generally happy with. They very kindly agreed to run some diagnostics for me and only to charge if/when they find and fix something. They suspected MAP or some other sensor(s) or perhaps the fuel pressure regulator and figured the other (non-Honda factory) shop may have simply been unable to chase it down. They also commented that running the bike up to temp might result in different readings than cold and since I was not there in person I cannot speak to whether all the dyno runs and prior checks were done hot or not.

I'm awaiting their word and will update accordingly. Wish me luck! :goofy:

wgregt

So....they only way to check or change a map on a PC5 is with a PC laptop?? So as a Mac-only guy, now I need to buy a PC to see what map I have currently (I got it used so I have no idea) or to change it??!!

Pretty much, unless you can run Windows on your Mac i.e. 'Parallels' or other. If you want, ride on over and I can extract the map for you, but even then this does not tell you what map you are running, it will only show you what the map settings are. I just recently downloaded a map for a buddy's '02 that had Leo Vince exhaust, we just grabbed an "off the shelf" map from Dynojet and it made a world of difference from what his had loaded in originally. Long story there, but he was not sure what the shop had used so I was able to reload a known setup and he was much happier now.

PorradaVFR

Wish me luck! :goofy:

VAYA CON DIOS!!!

Duc2V4

wgregtIf you want, ride on over and I can extract the map for you, but even then this does not tell you what map you are running, it will only show you what the map settings are.

The maps aren't named, it sounds like? So all you're seeing is air/fuel/gear settings? I guess we could write down what's currently in there, in case we needed to re-load it?

wgregt

Duc2V4

wgregtIf you want, ride on over and I can extract the map for you, but even then this does not tell you what map you are running, it will only show you what the map settings are.

The maps aren't named, it sounds like? So all you're seeing is air/fuel/gear settings? I guess we could write down what's currently in there, in case we needed to re-load it?

They are named but not if you retrieve them, all you can do is name it what you want at that point and save it to your computer, so you can always reload what you had. If you look at the files in the download section you'll see the name of the file, but once it's loaded the name doesn't stay with the file, at least that's what I have found. However, In addition to being able to reload what you had, the PCV can have two maps loaded and with a contact closure you can toggle between them, provided you don't have an Auto Tune module connected.

Was that dyno run done with the O2 sensors connected and the temp above 76 C?

My 09 sounds a lot like yours. I rarely see 200 km (125 mi?) to a tank and haven't since new. I thought the injectors may flow more fuel than the ECU was programmed for, which would cause it to be rich whenever the ECU goes open loop. Or it could be the wax unit, as it's about the only thing left to check.

I have a PCV and WB2 module installed, which did help. I just need to get more miles on it this year so the autotune can do its thing.

Argh. Just heard back from the shop and the good news is I have information, the bad news is that's it's...bad news.

1. Someone (NOT me) duct taped over the PAIR ports...based on the condition of the tape it was "years ago"...but the hose was not blocked and it was slopped, leaving some of the rubber ducts pinched. The PO did not strike me at ALL like a fiddler, so I have no idea what the hell that's about.
2. The O2 sensors are not fully heating up so they're not performing 100%...not sure how that affects their signal, but it's not right.
3. The TPS is bad...it's sending a warm-up signal all the time, meaning even a Power Commander would not be able to compensate for it..and the price quoted for a new one is nearly half what I paid for the bike to begin with. Ouch. They further note that the factor assembly uses safety screws so it cannot reliably be disassembled and even if it was there's no adjustment to make.
4. Bottom line - all told with parts it's looking like $2,000 to replace the whole deal. Nuts.

Does anyone have a 2002-2005 TPS/throttle assembly they don't need?

*sigh*

dawson

My 09 sounds a lot like yours. I rarely see 200 km (125 mi?) to a tank and haven't since new.

Damn. 125 miles per tank is worse than what I get!

What's a warm-up signal from the TPS? Kinda sounds like muffler bearings and headlight fluid... :s

PorradaVFR

Argh. Just heard back from the shop and the good news is I have information, the bad news is that's it's...bad news.

1. Someone (NOT me) duct taped over the PAIR ports...based on the condition of the tape it was "years ago"...but the hose was not blocked and it was slopped, leaving some of the rubber ducts pinched. The PO did not strike me at ALL like a fiddler, so I have no idea what the hell that's about.
2. The O2 sensors are not fully heating up so they're not performing 100%...not sure how that affects their signal, but it's not right.
3. The TPS is bad...it's sending a warm-up signal all the time, meaning even a Power Commander would not be able to compensate for it..and the price quoted for a new one is nearly half what I paid for the bike to begin with. Ouch. They further note that the factor assembly uses safety screws so it cannot reliably be disassembled and even if it was there's no adjustment to make.
4. Bottom line - all told with parts it's looking like $2,000 to replace the whole deal. Nuts.

Does anyone have a 2002-2005 TPS/throttle assembly they don't need?

*sigh*

Ouch that's steep...I wouldn't spend $2000 on my vfr considering its close to half what I paid for it. My 2 cents, if you can't repair it in a couple of $$ then sell it and buy another vfr or any other bike you fancy.

For me, its not worth the head ache especially if you spend more time fixing it than riding it.

hopefully a good set of pair valve block plates ($20) would clear up the duct tape fiasco.

$150 TPS sensor (with extra airbox you can sell)

http://www.ebay.com/itm/like/291100093084?lpid=82

They didn't say the o2 sensors were bad, just that they weren't heating up. Maybe go PC and eliminate them?

dawson

What's a warm-up signal from the TPS? Kinda sounds like muffler bearings and headlight fluid... :s

^^^ Agreed - sounds like they're blowing a smoke screen. The only time I saw a bad TPS was in very high mileage units or where lots of moisture was present. Not that it can't happen . . . just seems unusual. $2,000 bucks seems ridiculously high for this job and it would be worth testing the TPS yourself if you can. The FSM shows plugging in a special harness to test it, but some 14 ga solid wire can be used to backprobe the connections to do the same thing. Maybe just clean up the tape issue in the PAIR system and see what happens. Any money that would go to new O2 sensors would be better put toward a PC and eliminate them.

Man, so many typos in my post...frustration?

So I shopped around and found the throttle assembly for far less. I agree on the O2 sensors, I'll quite likely just opt for eliminators instead of replacing those, leave the PAIR back to factory (open) and given that I got a smoking deal on the bike to begin with I'll absorb the ~$1k bill as belated cost. $4k for an ABS with 300 miles was too good to be true after all, I guess.

OK guys we need a little sanity here. I've pulled this model bike apart too many times to count and done a lot of diagnosis. Here's what I can tell you FOR CERTAIN:

• The VFR ECU has no "long term fuel trim". The O2 sensors ONLY kick in when the bike is cruising.
• Fitting O2 eliminators will completely STOP closed loop mode. This means that the ECU will not "adjust" fuel. Ever.
• Any bike running with O2 eliminators will stay in Open Loop mode permanently
• The PAIR valves are open by default and ONLY close in circumstances where the O2 sensors would normally kick in

So, what does all this mean? It means if you fit O2 eliminators, your fuelling issues have ZERO to do with the O2 sensors.

Now, about the TPS sensor being faulty. I cannot speak with certainty on this topic, but the VFR ECU is a mix of Speed-Density and Alpha-N fuelling. What this means is that at low-mid throttle positions, the ECU uses the Manifold Absolute Pressure (MAP) sensor to control the fuel mixture. At larger throttle openings, the ECU switches to "Alpha-N" which means the fuelling is based on only the Throttle Position (alpha) and the engine rpm (N).

What kind of things can go wrong here?

• Air leaks in the MAP hoses would probably make the bike run lean, not rich
• The TPS *could* be out of alignment. This could be checked by looking at the TPS screws to see if they have been disturbed, because they are glued and set in place once adjusted at the factory.

The reason the "TPS fix" is so expensive is that Honda won't sell you a TPS, you have to buy the whole throttle body assembly. I had a zillion spare parts for this bike, including an entire assembly. I sold it all to member MVinOZ so if you want to contact him to see if he has a throttle body handy, you could pick one up for very little.

I thought the solenoid for the pair valves is normally closed except when the throttle is closed ie decelerating and idle? Also maybe its the coolant temp sensor sending out the wrong voltage telling the ecu to give it more fuel because its supposedly not up to temp?? Not a expert just throwing out ideas

PorradaVFR

Argh. Just heard back from the shop and the good news is I have information, the bad news is that's it's...bad news.

1. Someone (NOT me) duct taped over the PAIR ports...based on the condition of the tape it was "years ago"...but the hose was not blocked and it was slopped, leaving some of the rubber ducts pinched. The PO did not strike me at ALL like a fiddler, so I have no idea what the hell that's about.
2. The O2 sensors are not fully heating up so they're not performing 100%...not sure how that affects their signal, but it's not right.
3. The TPS is bad...it's sending a warm-up signal all the time, meaning even a Power Commander would not be able to compensate for it..and the price quoted for a new one is nearly half what I paid for the bike to begin with. Ouch. They further note that the factor assembly uses safety screws so it cannot reliably be disassembled and even if it was there's no adjustment to make.
4. Bottom line - all told with parts it's looking like $2,000 to replace the whole deal. Nuts.

Does anyone have a 2002-2005 TPS/throttle assembly they don't need?

*sigh*

Ok gang, picked up the bike yesterday and did a long way home ride. I'm VERY pleased with the result. While not cheap (but not the $2k I feared either) the new throttle bodies, O2 eliminators and removing the duct-tape "fixes" have made a very significant difference and improvement to the bike. Off-idle throttle is butter smooth, the VTEC changeover is all but invisible and while I do not yet have any idea what the fuel mileage will be I can say with certainty that she's no longer exhibiting the snatchiness that I was noticing after picking her up from the first shop.

The dealer also noticed (and SHOWED me) that the bike was giving a #8, #23 and #24 code - (TPS and O2 sensor heaters). The mechanic also showed me how to read the codes and cleared the repaired ones from the system.

** Sidenote - I have the service manual but cannot find where the codes are listed, does someone have that?

So basically the O2 sensors were not heating to spec so they were sending a bad signal, the PO had messed with the air box so it was not flowing as it should and the TPS was sending a bad signal that a Power Commander would not have corrected for. So while I'm in for more than I wish, I got a smoking deal on the bike to begin with so basically I've now paid a fair price for it. I'm very pleased how she's running now and may well go back to shop #1 to replicate the dyno run and see how she's behaving now.

Thanks everyone for the input. I have the removed throttle bodies, fuel pressure regulator (was fine, but was included with the new throttle bodies) for sale in classifieds if anyone wants to mess with it, or needs to scavenge parts from one.

Finally the saga ends well!

:goofy:

I have not checked this thread since you posted this update. Is it still running well? Have you measured your mpg?

I've just run down what remained of the tank when was in the shop and added around 60 miles on the new tank. Very vague, but the first "block" on the fuel gauge took about 18-20 miles which is at least a visual improvement.

I'll post up on the next fill since the last included the shop test-riding it and I would not know how much time idling might have affected the mileage seen. She's running great, still pleased with the results.

So filled up yesterday. 107 miles, 3.5 gallons. Yeah, 30.5 mpg by my math. I still note her running much smoother but that's not what I expected. May well re-dyno her to see if the FAR is improved as expected. If the numbers are better I'll live with the mileage I suppose. Hmmm

Nuts.

:ohmy:

Havagan

Nuts.

You ain't kidding. She definitely running smoother as I had clearly become accustomed to the snatchy off-idle throttle so the improvement there was notable...but not $1700 better. :goofy:

Like I said, I'll likely end up back at the original shop to run her on the same dyno. If the numbers are better I'll likely take the side cases off for a tank's worth and see if the mileage comes up to where I'd expect. If not and the dyno shows a better FAR I'll just call it a day and accept she's thirsty.

Looks like there are 2 marinas on a lake just northwest of Paso Robles that sell real gas...buyrealgas.com or pure-gasoline.com ... I would not hesitate to see how it ran on real gas.

I am not saying that will magically restore the 25% you are down on power and up on fuel consumption but I know the blends that they require in your area are quite troublesome for the refineries. I would run a tank of pure gas just to see, and your panniers are taking a 3-5% hit on he fuel economy as well but they wouldn't impact your hp numbers.

I sure seems from your dyno chart that you are running on 3 cylinders...I guess you have already confirmed that it is not the case but wow, 75 hp or so is pretty disappointing.

Call a few marinas in your area and see if they have pure gas or real gas available.

CornerCarver

Looks like there are 2 marinas on a lake just northwest of Paso Robles that sell real gas...buyrealgas.com or pure-gasoline.com ... I would not hesitate to see how it ran on real gas.

I am not saying that will magically restore the 25% you are down on power and up on fuel consumption but I know the blends that they require in your area are quite troublesome for the refineries. I would run a tank of pure gas just to see, and your panniers are taking a 3-5% hit on he fuel economy as well but they wouldn't impact your hp numbers.

I sure seems from your dyno chart that you are running on 3 cylinders...I guess you have already confirmed that it is not the case but wow, 75 hp or so is pretty disappointing.

Call a few marinas in your area and see if they have pure gas or real gas available.

The dyno chart I posted was before the repairs were made and as I noted, they were substantial. I do need to re-run it, hopefully to reveal the bike is as it should be from a HP/torque/fuel-air ratio. If those are now better aligned to expectations I'll tolerate the fuel mileage. If not...well hell, I dunno. Not going to keep spending money on it when she's not at all unpleasant to ride.

That makes sense Porrada, we took our 3rd Gen to have it dyno tuned after rebuilding the carbs...it was 76 hp before and 93 hp after installing a jet kit and tuning the carbs a bit.

But that bike is 23 years old and I would question the sealing of the valves and rings on that bike.

Maybe the bike isnt going into closed loop mode? Im no expert but I know one my bike warms up you can hear the pair valve solonoid click off when revved to 1500rpm from idle. I know the pair has to shut itself off when the bike is running from the o2 sensor to avoid any misreadings.

These suggestions are out in left field, so feel free to ignore them.

First, you're still reporting low mileage for the amount of gas that the bike is consuming. We assume that the # of gallons that you are pumping is accurate (that the gas pumps are correct), but what about the distance you are traveling? Some bikes have relatively-accurate odometers from the factory, but that's not a given. And a lot of people will change out sprockets to increase acceleration - but at the cost of higher engine speed at any given road speed (and also affecting the odometer accuracy, if that is driven off the rear wheel / drivetrain). You may want to run 100+ miles on the highway, using the highway mileage markers (or using a GPS), and then see how much gas you used. You may find that your odometer is off, and that your mileage is decent.

Second, are there things that could be affecting your rolling resistance? I assume you're not riding around on 15 psi in your tires, but it would be a good idea to double-check your tire pressure. Also, check that your drive chain is properly lubricated & not adjusted too tight. And check that you don't have any issues with one of your brake calipers dragging. (If you put the bike up on the centerstand, with the rear wheel of the ground, and you leave the bike in neutral with the engine turned off, how freely can you spin the rear wheel by hand? How much resistance do you feel?) While I'm thinking of it, it couldn't hurt to check front wheel bearings & rear axle bearings, too - although that's not as easy to do.

Again, these are out in left field, but I didn't see any mention of these, so I thought I'd suggest them.

Good luck!

Ron

CornerCarver

Looks like there are 2 marinas on a lake just northwest of Paso Robles that sell real gas...buyrealgas.com or pure-gasoline.com ... I would not hesitate to see how it ran on real gas.

I am not saying that will magically restore the 25% you are down on power and up on fuel consumption but I know the blends that they require in your area are quite troublesome for the refineries. I would run a tank of pure gas just to see, and your panniers are taking a 3-5% hit on he fuel economy as well but they wouldn't impact your hp numbers.

<snip>

Call a few marinas in your area and see if they have pure gas or real gas available.

+1 to that suggestion. Try running an entire tank of ethanol-free gas if you can find it anywhere, and see what sort of mileage you get from that.

Also, in addition to the sites above, I find http://www.pure-gas.org/ to be very useful.

Good luck!

Ron

<Darth Vader voice> The cycle is now complete....(hey, just realized there's a pun there too). :goofy:

So - took the VFR back to the original shop to have her re-run on the same dyno to hopefully quantify the impact of the repair work done by the dealer. Sure enough, the FAR is much improved, with slight improvement to the power/torque lines but I must note the prior chart did not hit the top of the rev range. At this point with a few tanks through with 30-31mpg I'm going to put this dog to rest and accept that mileage and be happy with the better fuel/air mix that is as closer to as it should be.

[image: post-2418-0-40151000-1399912812.jpg]

My current tank is not from Costco which has switched to a blended fuel over here. Maybe that will have an impact, but I'm not holding my breath. I'm just gonna ride Dusty as she is. :comp13: