Fried ECU again, why???

Ok, so in April at the track day at Spa-Francorchamps, my VFR fried the original ECU from late 1995. I replaced it with one from eBay, and now that one is fried as well. Does anyine here have any ideas as to what would be killing ECU's on my VFR? This is an issue that I'd really like to sort out, as I don't want to keep throwing ECU's at her, just for her to eat them on a regular basis. Any ideas would be helpful, as I have my own theories, but am not sure how sound they are. Thanks!

your bike is not grounded properly...... pm sent...

How is your charging voltage? Do you have a permanent voltmeter installed on the bike?

I do not have a volt meter installed on my bike, but haven't had any issues with the battery that I'm aware of, as it's only 1 year old. I'll look around for a bad ground in my wiring harness, but that's going to take time to find all the ground points. I know of a few, but not all.

As far as the link goes, I already have the upgraded R/R on my VFR, as well as Tightwads upgraded R/R wiring harness installed. So what exactly am I supposed to do with my ECU? I'm not very electrical savvy, and am much better with nuts and botls, and fabricating parts to fit, than I am with electricity. I'll probably give this a shot with my R/R, as it can't hurt, but still need turn by turn directions on what to do with the ECU, thanks!!!

Well technically it's not an ECU but an ignition computer with a programmed timing and dwell map.

Can bad ground fry these?  I would have thought they'd mostly be damaged by issues with the coil packs.   Something to do with flyback voltage spikes for example.

To me, a bad ground doesn't necessarily make sense, but again, I'm not an electrical wiz, so I don't really know. As far as the coils go, wouldn't there be some other indication of those going bad, besides  killing off ECU's, but again, I'm really grasping at straws here, and this is why I'm asking for help, as I don't really have a clue!!!

I have a spare that I bought for my now crashed 4th gen. Let me know if you want it. It will cost you freight from Denmark only.
It is originally from a UK bike with 40000miles if that matters.

VFRD to the rescue............   magic :fing02:

[image: View Post]kox, on 13 August 2012 - 02:42 PM, said:

I have a spare that I bought for my now crashed 4th gen. Let me know if you want it. It will cost you freight from Denmark only.
It is originally from a UK bike with 40000miles if that matters.

I'll take it!!! My address is below, and please let me know how much I owe you, and how to get the funds to you. Thanks!!!

Douglas Cook
PSC 9  Box 4586
APO AE 09123
Flugplatz Spangdahlem
54529 Spangdahlem
Germany

Doug, I wounder if its just bad luck as the one from e-bay fired, can be from a high milage bike. But I think the first one might has damaged from the fact your rear coils was cocked by your exhaust during the Mugello trip. Might also be the coils has some damage you cant se by eye or mesurable as coils are cold, just pops up as they get warm? Where is the ECU located on a 4th gen? just ounder if changes to your bike might do the ECU rund hotter than it should? just my 2 cent......................

But good news your close to get a working one.

Great that VFRD is the place to find a fast rescue!

I was also wondering if the coils are part of the problem. I may install the hayabusa coils, but don't really want to fry another ECU, so I'm on the fence about that. I might also get a different set of VFR coils, and swap out the ones I have. We'll see what happens I guess. I'm going to see if I can re-mount the ECU to a better location as well, but it all depends on how much slack I have in the wiring harness. Fortunately VFRD has been very helpful!!!

[image: View Post]douglasthecook, on 14 August 2012 - 12:48 AM, said:

[image: View Post]kox, on 13 August 2012 - 02:42 PM, said:

I have a spare that I bought for my now crashed 4th gen. Let me know if you want it. It will cost you freight from Denmark only.
It is originally from a UK bike with 40000miles if that matters.

I'll take it!!! My address is below, and please let me know how much I owe you, and how to get the funds to you. Thanks!!!

Douglas Cook
PSC 9  Box 4586
APO AE 09123
Flugplatz Spangdahlem
54529 Spangdahlem
Germany

I'm on vacation now - will ship early next week. I also have a spare harness that as far as I remember I only took the light sockets off. Do you want that as well? It will add weight which will increase the freight costs.

Actually, from August 28th to August 31th I'm staying in a B&B in Vielsalm, Belgium. If you like you can pick it up there?

 kox, on 14 August 2012 - 01:27 PM, said:

Actually, from August 28th to August 31th I'm staying in a B&B in Vielsalm, Belgium. If you like you can pick it up there?

I'll take the harness as well, if you don't need or want it, and picking it up in Belgium shouldn't be a problem, as Vielsalm is about an hour away from Spangdahelm. It'll have to be in the evening, unless I can manage to escapre from work early. Let me know what date, and time works best for you. Thanks!!!

This is a little better explanation of what's happening, and what's not happening...

Basically what happens is when I turn the key on, and depress the start button, the bike tries to fire, but won't start. fuel and air is good, not getting any spark to the plugs. The manual has me check the side stand switch, the pulse generator, and a few other things finally getting it down to the ECU. Just like last time, the bike started running rough, like it was mis-firing really bad, on 3 cylinders, then it just wouldn't start. I may have a bad coil, and that could be killing the ECU, but I'm not 100% sure about that, as there isn't a way that I can check my coils out now, as they're not getting a signal to fire from the ECU.

Until you've swapped your "bad" ECUs into another 4th-gen (and which causes it to experience the same symptoms) I would not suspect that the ECUs have been fried.  I probably wouldn't want to risk frying another ECU (even a known working one) in your bike until you do that, but I cannot see any risk to someone else's bike by trying your "bad" ECUs.  ECUs just don't normally fail.  Good luck.

Ciao,

 JZH, on 15 August 2012 - 01:28 AM, said:

Until you've swapped your "bad" ECUs into another 4th-gen (and which causes it to experience the same symptoms) I would not suspect that the ECUs have been fried.  I probably wouldn't want to risk frying another ECU (even a known working one) in your bike until you do that, but I cannot see any risk to someone else's bike by trying your "bad" ECUs.  ECUs just don't normally fail.  Good luck.

Ciao,

Unfortuantely as much as I'd like to do that, my VFR is the only one around in my area. The first time that this happened, Leon was kind enough to send me his working ECU, and I installed it. My VFR fired right up, and ran just fine. I only let it run for a minute or so, as to not fry his ECU. I'm going to look at relocating the ECU from where it sits currently, as well as replacing the coils, as those might be one of the reasons that the ECU is getting fried.

 douglasthecook, on 15 August 2012 - 12:42 AM, said:

 kox, on 14 August 2012 - 01:27 PM, said:

Actually, from August 28th to August 31th I'm staying in a B&B in Vielsalm, Belgium. If you like you can pick it up there?

I'll take the harness as well, if you don't need or want it, and picking it up in Belgium shouldn't be a problem, as Vielsalm is about an hour away from Spangdahelm. It'll have to be in the evening, unless I can manage to escapre from work early. Let me know what date, and time works best for you. Thanks!!!

PM

 douglasthecook, on 15 August 2012 - 12:51 AM, said:

as there isn't a way that I can check my coils out now, as they're not getting a signal to fire from the ECU.
The only way to measure the signal is with a oscilloscope and I don't think you have one of those.
Have you measured the primary coil resistance of all four coils?

[image: Posted Image]

[image: View Post]V4 Rosso, on 15 August 2012 - 09:31 AM, said:

[image: View Post]douglasthecook, on 15 August 2012 - 12:51 AM, said:

as there isn't a way that I can check my coils out now, as they're not getting a signal to fire from the ECU.
The only way to measure the signal is with a oscilloscope and I don't think you have one of those.
Have you measured the primary coil resistance of all four coils?

[image: Posted Image]

I have not had a chance to do that yet. That was going to be my next step, but I just haven't had the time.

Too high a voltage is not good for ECU's.  Run a check on the charging voltages whilst you have the multimeter out.  A new battery will survive high charging volts much better than sensitive devices like ECU's.

If the bike charging system is noisy, ie spikes on the 12Vdc system, or really high volts, you are looking at these being introduced to the ECU's supply and possibly "frying" it.
I am no expert on the actual contents of an ECU, which considering the electrical problems espoused in these pages are reasonably robust pieces of electronics (thank goodness for that).  Most switching devices (which an ECU does in response to it's multiple inputs and application of Honda built in buggery factors) just earth the coil of whatever it is they are controlling.  For damaging spikes to be introduced to the ECU from this action I would suspect some sort of grounding problems.

When my various RR failures come around it is the stuck around 17+Vdc that worries me most in comparo to low volts which just leaves the battery uncharged.
Perplexing problem, good luck.
Mike

[image: View Post]swas, on 16 August 2012 - 03:01 AM, said:

Too high a voltage is not good for ECU's.  Run a check on the charging voltages whilst you have the multimeter out.  A new battery will survive high charging volts much better than sensitive devices like ECU's.

If the bike charging system is noisy, ie spikes on the 12Vdc system, or really high volts, you are looking at these being introduced to the ECU's supply and possibly "frying" it.
I am no expert on the actual contents of an ECU, which considering the electrical problems espoused in these pages are reasonably robust pieces of electronics (thank goodness for that).  Most switching devices (which an ECU does in response to it's multiple inputs and application of Honda built in buggery factors) just earth the coil of whatever it is they are controlling.  For damaging spikes to be introduced to the ECU from this action I would suspect some sort of grounding problems.

When my various RR failures come around it is the stuck around 17+Vdc that worries me most in comparo to low volts which just leaves the battery uncharged.
Perplexing problem, good luck.
Mike

I'll try that once I get my bike running again. Who knows, maybe I'll add a voltmeter, we'll see!!!

Coil impedence out of spec, High charging system voltage and volt drop across the grounds are the things you need to check.

This is a great page that explains how and why to perform a loaded voltage drop test (four your grounds)  http://www.crookedri...op-testing.html

Doug, can you please remove your RC tail bodywork and take/post pictures of your setup?

Will do

[image: View Post]SEBSPEED, on 16 August 2012 - 09:00 AM, said:

Doug, can you please remove your RC tail bodywork and take/post pictures of your setup?

Will do!!! I'll take the pics tonight, and post tomorrow...

[image: View Post]douglasthecook, on 15 August 2012 - 02:07 AM, said:

Unfortuantely as much as I'd like to do that, my VFR is the only one around in my area. The first time that this happened, Leon was kind enough to send me his working ECU, and I installed it. My VFR fired right up, and ran just fine. I only let it run for a minute or so, as to not fry his ECU. I'm going to look at relocating the ECU from where it sits currently, as well as replacing the coils, as those might be one of the reasons that the ECU is getting fried.
Did it work when he got it back? :tongue:

You could still send him one of your "fried" ones and see if it works in his bike... (Yes, I'm still skeptical!)

FWIW, the reg/rec on my 3rd-gen failed in overcharge mode and I ended up boiling not one, but two batteries completely dry (this was long before I'd discovered the collective wisdom of VFRD!), and my ECU still worked just fine, so a bad reg/rec is probably not your culprit.

Ciao,

[image: View Post]douglasthecook, on 15 August 2012 - 12:51 AM, said:

This is a little better explanation of what's happening, and what's not happening...

Basically what happens is when I turn the key on, and depress the start button, the bike tries to fire, but won't start. fuel and air is good, not getting any spark to the plugs. The manual has me check the side stand switch, the pulse generator, and a few other things finally getting it down to the ECU. Just like last time, the bike started running rough, like it was mis-firing really bad, on 3 cylinders, then it just wouldn't start. I may have a bad coil, and that could be killing the ECU, but I'm not 100% sure about that, as there isn't a way that I can check my coils out now, as they're not getting a signal to fire from the ECU.

Sound like the same syntoms you had during the Mugello trip, untill we put the rear coils back up from beeing ziped to the shock, and cooked by the exhaust. Well, the oil light that flashed on then is missing thro. So can it be your conections to the 1kRR(wasint it that you had?) dash that cosing this?

[image: ECU 3]ECU 3 Current location of ECU
Ok, this is where my ECU has been sitting since 2008. I'm going to relocate it to the left side of the sub-frame, and have made a mounting bracket for just that. I'm not sure that this position is the problem, simply because it's been mounted there since 2008, and I have not had any problems with the ECU until this year. The location and position that it will go to will be much closer to the standard factory position. I still need to check the resistance on the coils themselves. Hopefully that'll tell me if the coils are bad or not, as everything else is checking out ok, sorta...The Pulse Generator is supposed to give a reading of 450-550 ohms at 68 degrees, and I was getting 313 ohms, so it's less resistance, but I'm not sure how less resistance would fry my ECU.

Hi Doug,  do telll me in time if your want/need to ride biatch to the WSBK at the Nurburgring next month; so I can put the passenger pegs on for you......   :owned:

[image: View Post]douglasthecook, on 20 August 2012 - 07:37 AM, said:

The Pulse Generator is supposed to give a reading of 450-550 ohms at 68 degrees, and I was getting 313 ohms, so it's less resistance, but I'm not sure how less resistance would fry my ECU.

Thats a 30% to 45% lower resistanse than the ideal, so start to sound you found the the reason, but what did make the Pulse Generator change resistanse?

So check the coils for sure, as the wires to them, as they where hanging in them (partial) last summer. Also you did use the space under the pillion seat as luggage store under the Mugello trip, so the ECU might have run a bit hot during the trip, and what it did to the Pulse Generator is also a question. But as you did have some bad running also at the trip, and starting was not that good ither, I would change the Pulse Generator and see how it effects. Sounds like its the main problem here.
Less resistanse gives higher voltage , and high voltage burns, right? Just my 2 cent...................

I may change the pulse generator, I still have some troubleshooting to do as well...we'll see what happens when that's completed.

[image: View Post]douglasthecook, on 20 August 2012 - 07:37 AM, said:

.The Pulse Generator is supposed to give a reading of 450-550 ohms at 68 degrees, and I was getting 313 ohms, so it's less resistance, but I'm not sure how less resistance would fry my ECU.
Where did you get those numbers from as the Honda Factory service manual states 200-400 Ohms at 20C/63F so you are good.

[image: View Post]keny, on 21 August 2012 - 12:40 AM, said:

Less resistanse gives higher voltage , and high voltage burns, right? Just my 2 cent...................
Less resistance most often leads to higher current and high current is often a bigger problem than high voltage. But in this case it doesn't make that much of a difference as the coils in the PG are only producing a very low voltage and minimal current, just enough to provide a timing signal for the ICM. The ICM is not sending any current through the coils of the PG.

page 16-6 of the service manual

[image: View Post]V4 Rosso, on 21 August 2012 - 10:25 AM, said:

[image: View Post]douglasthecook, on 20 August 2012 - 07:37 AM, said:

.The Pulse Generator is supposed to give a reading of 450-550 ohms at 68 degrees, and I was getting 313 ohms, so it's less resistance, but I'm not sure how less resistance would fry my ECU.
Where did you get those numbers from as the Honda Factory service manual states 200-400 Ohms at 20C/63F so you are good.

[image: View Post]keny, on 21 August 2012 - 12:40 AM, said:

Less resistanse gives higher voltage , and high voltage burns, right? Just my 2 cent...................
Less resistance most often leads to higher current and high current is often a bigger problem than high voltage. But in this case it doesn't make that much of a difference as the coils in the PG are only producing a very low voltage and minimal current, just enough to provide a timing signal for the ICM. The ICM is not sending any current through the coils of the PG.

I was looking at the wrong part...right numbers, but wrong part...I must be getting old, as it appears that my eyes and brain aren't working well together lately...It was the pulse generator coil that was supposed to read between 450-55- ohms, and it was reading 313 ohms from page 16-6.

Hmmm maybe not. Depends on where you first measured the resistance. I have no clue why the numbers differ when measured at the ICM connector (P16-6) compared to those from when you measure them at the PG connector (P16-7). Weird.

[image: View Post]keny, on 21 August 2012 - 12:40 AM, said:

I would change the Pulse Generator and see how it effects. Sounds like its the main problem here.
Less resistanse gives higher voltage , and high voltage burns, right? Just my 2 cent...................

The pulse generator could well be faulty, but there's no risk of voltage issues caused by it.  Pretty much all Honda pulse generators are Variable Reluctance Sensor (VRS) AC voltage generators using two wires.  As the teeth on the metal timing wheel pass by the pulse generator, it generates an AC pulse.  At idle it's about 0.7 volts peak, and it increases as rpm rises, but it's only something like 10 volts AC - pulsed!

The voltage pulses are seen by the ignition computer, which calculates engine rpm and crankshaft position from these.  A programmed map within the computer sets ignition advance and dwell time for each spark based on engine speed

Common problems with pulse generators is the breakdown of the coils inside them.  A low resistance reading would mean the coil is shorting and therefore it would generate much weaker pulses.  Pretty much similar to a stator failure, really.

I'd either grab a waveform of the pulse generator output using a Digital Oscilloscope, or just replace it.  2nd hand ones are cheap.

Ok, so I did more troubleshooting last night, and this is what I found...The ignition pulse genetator coil at the ECU/ICM plug is supposed to read between 450-550 ohms, mine is reading 313 ohms. All four coils are withing spec and are reading 3 ohms. The spark plug caps are also within spec reading a solid 19 ohms. The pulse generator  readings at the black plug at the pulse generator end was reading 312 ohms if I remember right, regardless it was within spec. The only things not checked were the side stand switch, and the neutral switch, as my wiring is pretty much disconnected right now. I'm running out of things to check, and I'm still curious as to why I'm only getting 313 ohms at the ICM/ECU plug for the pulse generator, when it checks good at the other end.

At this point I'd bring out the lab scope.   This is what I'd use if I was doing it. http://www.seeedstud....html?cPath=174

 kaldek, on 23 August 2012 - 01:23 AM, said:

At this point I'd bring out the lab scope.   This is what I'd use if I was doing it. http://www.seeedstud....html?cPath=174

That's a cool tool, but I'd have no idea how to use it. I'm just now getting proficient with my multi-meter!!!

Try disconecting your speedo sensor it plugs into your gearbox sprocket housing one day my bike was fine then it stopped everything worked apart from it would not fire i replaced this unit and the bike was fine.

[image: View Post]george6x, on 05 September 2012 - 12:32 PM, said:

Try disconecting your speedo sensor it plugs into your gearbox sprocket housing one day my bike was fine then it stopped everything worked apart from it would not fire i replaced this unit and the bike was fine.

Thanks for the tip, I'll have to remember that one! I was able to get my VFR working, although she is still not 100%. There is still a misfire, and I'm working on replacing the suspect components.