FI light and TPS related issue

Just to give some background to my problem here. Took my bike to a reputable shop to get the valves adjusted along with all the fluids flushed and the rest of the mechanics and wires checked. They replaced some crusty hoses but said that everything seemed okay. The bike at 50,000 miles ran like a dream until about a week after I was getting a rough response and an FI light.

At first I was getting .5 second 8 fi light blinks when we would turn the key in the first position in the ignition. The symptoms were the bike, at standstill, seemed like it was choking for gas until it started rolling and in the higher rpms. The next day the FI was just staying on continuously but only if I really opened up the throttle especially after 5k rpms. The symptoms were the same though, choking for gas it seemed like. Cruising on the freeway at 75 mph and right at about 5,000-5,001 rpm lets say and the bike would kind of lunge without me blippin the throttle. The thing is, I can go off on a side street and turn the bike on and off again for about 2-3 times and it will restart the light, as in turning it off, and the symptoms will go away until a little bit later. Now the FI will blink 8 times or stay on continuously; never seeming to make a final decision. 

With some searching on this forum it sounds like a bad tps sensor. Question: do these sensors go bad after 50,000 miles? Is there any scenario where it can get "cleaned"? And if the throttle bodies are no longer available, at least on partzilla,  and you cant get a new sensor without buying an entire assembly then how do we get a new sensor? Is there a 3rd party website that sells these sensors by themselves? I'm about to buy a used one but wanted to ask for any help before I do that. Plus, the used one I'm looking at is from an 00' and I have a 98'. Will there be any issues? Thanks you guys. 

:lurk:

Look, I've read the manual and I know what the symptoms are pointing to. Hence the title of the thread; just wanted to give context. I'm not trying to be lazy here. Anything beyond a little emoticon would of been appreciated since the same amount of effort could of been put in. 

This would certainly be a coincidence if a component went bad just after the service. 

Run it hot, or get it to act up, then open the tank. Get a "whoosh"? That can indicate that they crushed a vent vacuum hose when reinstalling the tank, and it only shows a problem once the vacuum builds up, like after your 5k RPM run.

Given that the symptoms disappear I wonder about a loose connection particularly on the ground side. That could result in any crazy symptoms. This could be something that was not tightened by the dealer and worked its way loose. Silly question: Are the battery terminals tight? After running it, put an ohmmeter between the negative terminal and the frame, got zero ohms? 

Have you called the dealer? Even if it is their error, they know what they touched and may be able to zero in on it, if they are willing to help based on how quickly this happened after service.

Thanks Knight. I talked to them once before and we've only consulted the manual. Will follow the steps you've outlined. 

Ok, since they replaced crusty hoses, I'm guessing they did the little ones under the throttle body.  This means they most likely disconnected the TPS.  Step one is to check the TPS connector and make sure that it is tight and hasn't become disconnected.  If it ran right for a couple days there is the possibility that it worked its way loose if it wasn't fully locked in.  Check to make sure the wires/terminals are firmly seated in the connector backshell.  There could also be some debris or corrosion between the terminals that could be solved with some contact cleaner and unplugging/replugging the connector a couple times

You should be able to check the tps with a multimeter, it is basically just a rheostat/variable resistor.  If the TPS checks out ok, resistance-wise, then you would move to checking out the ground and +12v supplied to it.

I'm fairly certain all vfr 800s and the rc51 have the same TPS, IIRC.

TPS Resistance Check:

1.  Prop tank

2.  Remove air filter lid.

3.  Remove air filter and lower box - you will have to remove the screws holding in the throttle body trumpets and rear ignition coils

assembly - Take note of vacuum line locations and any connectors removed, phone pictures are good.  There are a couple hose and sensor connections on the bottom of the box that will require you to lift the box slightly and disconnect.

4.  Locate TPS at right rear throttle body

[image: large.20160630_123452.jpg.2f85c6edfda229]

5.  Disconnect grey connector from black TPS.

6.  Take 3 measurements on the TPS corresponding to the wire colors at closed throttle (CT) and wide open throttle (WOT)

[image: large.20160630_123503.jpg.a749c1affc654e]

Resistance readings from my good TPS as follows:

----------------------------- (CT) ---------------- (WOT)                         

Pink - Light Green......... 5k ......................... 780

Pink - Green/Brown....... 5k ......................... 5k

L. Green - Green/Br...... 900 ....................... 5k

If it all checks out, then the TPS is just fine.  (* note, that wire is annotated as Green/Orange on the wiring diagram; not Green/Brown)

If good, I would reassemble at this point.  Paying attention that all connectors are well seated and cleaned.  Then I would disconnect and clean the big connectors to the ECU and clean/reattach the ground on the right side of the chassis.  Make sure that you don't forget the wires and hoses connected to the bottom of the air cleaner when re-assembling.

Thank you. I checked all the 'superficial' things that I could and all of it checked out. My entire tool box was recently stolen so even digging down to the sensor might mean making another trip to the mechanic, which is frustrating to say the least. I bought a spare 'low mileage' TPS sensor for cheap, with another buyer lined up if I end up not needing, plus the mechanic is willing to help me out with a very discounted rate or at least help out with some tools on site. (I'm able to do the work and they've become good friends of mine.)

Story: The mechanic use to ride a 00' vfr and did a lot of cross country trips and continuously reminds me it's still one of his favorite bikes. He regretts selling it every day. The love for his old bike definitely has transferred to mine and I can always tell that no matter what I've sent the bike in for, it leaves with with a clean and lubed chain and an entire quick detail.  Most likely things have been left in check but 'good feels' doesn't make for 100% assurances. 

Thank you Knight again and thank you MadScientist. Really appreciate it you guys. Will follow these steps most likely next week/weekend. Will try to confirm if the censors are identical.

Hey guys. Perhaps I should make a new thread about this. 

......... so the problem.... it came back. After installing the sensor and a couple of months of GREAT riding I have the 'surging' issue. It feels almost like the gas is cutting out or the brakes are being tapped ever so slightly. The FI light either comes on, and stays on, or it just stays off. Either way the problem continues now at any RPM. Anyways I have a very weird condition happening here and I'm bringing this thread back from the dead to ask it. I have a wolf exhaust and so it has the metal plate to separate the exhaust and the computer. I've put some padding on top of the plate where the ECU sits but I've noticed that if I put even more padding, to absorb the vibrations, that this problem doesn't seem to happen. Okay... so question. I've never had a stock 5th gen VFR without a wolf exhaust, and I've had two vfrs. What is Honda's solution to this? Also, would vibrations really start making the ECU become finicky. These bikes are becoming old and something like that just sitting on a metal plate could start slowly becoming 'undone'. Anyone would help and be appreciated. 

FI light blinking in my case and many others has been a ground issue. The bike will can run fine and then hesitate or miss, or just die, then start up normal in 5 minutes.

In short...There is a orange covered ground block on the left side, solder together, two wires from the black box to the wiring harness, cut and make direct connection to the frame, improve all grounds to frame, install Vrfness from wiremybike.com

There is lots of info on this form, search Fi light.

Oh no definitely. The weird part is my bike, when bought, came with a vfrness. Perhaps it was installed improperly ( didn't look like it) but it was actually the cause of some of my past charging problems. I will do what you've mentioned of course though. Making new grounds can never hurt haha. Weird thing is though, I wrapped the ECU with a nonflammable /static material, that cushions the vibrations when riding, and I have absolutely no problems. Perhaps there is something in the wiring harness, right before the computer, that is minutely frayed and causing these problems when it moves up and down. Upon further inspection I can't see anything but these harnesses are so jam packed that only a trip to hell and back might be a solution if that is indeed the case. This might be one of those electric gremlins the VFR is famous for, that is only the start to my problems.