5 gen grounding problem - will 1998/1999 wiring harness [and ECU] work on 2000/2001 VFR?

[sfdownhill]

First please allow me to shoot a super huge metric ton of thanks to VFRD member Mohawk! He talked me through some of the finer points of his Yoshi-style dual velocity stacks and big airbox mod. As with the header project, couldn't have done it without him

 

 

Problem in a nutshell:

 

-Grounding problem rears its ugly head at higher rpms - engine cuts out then comes back on, rinse repeat a dozen times or so until it quits for good.

 

-The last time it died for good and coasted to a stop, a few wisps of smoke came out from under the dash and it smelled of very hot wiring insulation.

 

-Three hours later at lunch break the crash truck brings the poor VFR back to the pits - all the way to my pit, which is more than really needed. Thanks FunTrackDayz crew! Fuel pump wouldn't prime, pulled fuel pump connector and tested - no voltage. Tested across the FI/IGN/PUMP fuse - no voltage.

 

-12 hours later and fully cooled down, the bike started up, idled, and ran, though the tach remained inoperative, pegged at zero.

 

-The professional mechanic who is working hard to solve the problem wants to install an entire new [used] wire harness.

 

-We have found two 1998/1999 harnesses, both in great shape. But 1998/1999 VFR's don't have a catalytic converter or O2 sensors -  mine is a 2001, so it has a cat converter and two O2 sensors.

 

-QUESTION: Can a 1998/1999 VFR wire harness [and 1998/1999 ECU if necessary] be installed and work well on a 2000/2001 VFR?

 

 

Longer version:

[1] Almost 3 years ago, my 60k mile 2001 would start and idle, but died immediately when rev'd over 2500rpm. The exhaust smelled very rich, so I thought an injector or two were stuck, and I got all involved with a new V4 mistress. Mistress shown here:

 

 

November 2021 I moved to a new city for a new job, and along the way, lucked into a relationship with a certified Ohlins suspension tech named James who also happened to make custom captive axle spacers for race bikes. One thing led to another, and we did a bunch of mods barely touched on in the photos at the end of this post. The engine got a valve adjustment, starter valves synched, new AS3 silicon coolant hoses, thermostat, coolant, oil, filter, double velocity stacks, and a Rapid Bike Race with My Tuning Bike autotune module.

 

[2] During static engine test runs at the craftsman's shop after the mechanical work, the engine would sometimes cut out - die. James and his partner Mike worked very hard to find what appeared to be a problematic ground on one of the bike's circuits. James thought it might be a bad ECU, so superstar VFRD member Duc2V4 went through his VFR inventory, came up with three different 5 gen ECUs, and ran them over to James's shop for testing.  They ended up with a good 49-state 2000/2001 ECU. Mike noticed that sometimes raising the tank would cause the pump to stop while priming. They couldn't find a broken/failed ground wire in the harness, so they added new ground wires to the suspected circuits. It seemed fixed. The dyno James usually uses wasn't available due to the tragic death of young MotoAmercia racer Jason Aguilar - his family owns the dyno. James couldn't street test the 5 gen because I had been silly and distracted enough to forget to give him the current California tags.

 

[3] I took the bike from James's shop, picked up Duc2V4 and his 5 gen, and headed to the track. Toward the end of the first lap of the first session, the bike started cutting out for around 1/2 second, recurring maybe every 15-20 seconds - randomly stopping running under acceleration around 8000rpm, then it would run again. I thought the cutting out was the autotune working on the fuel map, but as I started the second lap, the engine cut out and the tach dropped to zero, then the engine started back up again. Tach stayed on zero.. A few turns later, the sad VFR quit running all together and we coasted to a stop on a safe bypass road. A few wisps of smoke came out from under the dash and I smelled hot electrical wiring or components. The motorcycle cranked over but would not fire.

 

[4] Later at lunch break the crash truck brings the poor VFR back to the pits. Fuel pump wouldn't prime, so Duc2V4 borrowed a multimeter from Thomas the guy pitted next to us, and checked for voltage. He, pulled fuel pump connector and tested - no voltage. Tested across the FI/IGN/PUMP fuse - no voltage. 

 

It must be said that James is beyond competent as a mechanic, machinist, and as a track day promoter. I trust him completely and he felt terrible about my VFR quitting at the track.

 

We got back from the track day at 9:30 that night. James met us at his shop to take the bike back in and figure out the problem. The engine started and idled, rev'd a little, but the tach was still sitting at zero.

 

 

If it ends up that a complete wire harness swap is needed, the question remains:

"Can a 1998/1999 VFR wire harness [and 1998/1999 ECU if necessary] be installed and work well on a 2000/2001 VFR?

 

Here's the stuff that went on w my 5 gen [Scarlet]:

[Lorne]

As I recall, there are a number of green ground leads bundled together in the harness above the engine. Some owners have found corrosion at this junction to be the cause of electrical troubles.

 

If you haven't opened up the wiring in this area it is worth doing so to find out.

[Grum]

5 hours ago, sfdownhill said:

Three hours later at lunch break the crash truck brings the poor VFR back to the pits - all the way to my pit, which is more than really needed. Thanks FunTrackDayz crew! Fuel pump wouldn't prime, pulled fuel pump connector and tested - no voltage. Tested across the FI/IGN/PUMP fuse - no voltage

 

If you have No voltage at this Fuse, i.e. both sides of the fuse, you can forget the Grounds!

Even if you had a blown FI/IGN/PUMP fuse (Sub Fuse B 20amp) you must measure 12v on one of the two fuse test points on top of the fuse (incoming fuse power) irrespective of Ignition Switch On or Off.

 

Check the Main Fuse B 30amp next to the Starter Relay, its wiring and connections can suffer badly from overheating, burning and high resistance joints (see attached 6gen example). This fuse feeds the 12v power to the FI/IGN/PUMP Sub Fuse, and is renowned for causing intermittent and complete engine shutdown, loss of power from this fuse will also mean your Fi Light will be fully ON.

 

Also.......Main Fuse B 30amp provides your Headlight Power. So, what is the status of your Headlights?

 

[sfdownhill]

Thanks for the responses guys - we’ll check the main fuse B and its wiring. I do have a VFRness mini harness on hand, so can and will replace any wires that appear to have been overheated or damaged.

[Tirso]

I fried a PC5 and fused main fuse B by not checking it when I had similar problem as yours.

A new to me main fuse B and PC3 from eBay solved the problem.

Good luck with the gremlin.

 

Nice mods on your scoot! I have many questions but don't what to hijack your thread.  Any chance you're doing a "look what I did" thread? 

 

[sfdownhill]

1 hour ago, Tirso said:

I fried a PC5 and fused main fuse B by not checking it when I had similar problem as yours.

A new to me main fuse B and PC3 from eBay solved the problem.

Good luck with the gremlin.

 

Nice mods on your scoot! I have many questions but don't what to hijack your thread.  Any chance you're doing a "look what I did" thread? 

 

Tirso - thanks for letting me know you had the main fuse B problem too.

 

Yep, I’ll do a ‘look what I done’ thread on the mods.

[raYzerman]

What they said........ but just saw this if you're going down that road.........

https://vfrworld.com/threads/5th-gen-parts-for-sale-sargent-seat-ecu.60057/#post-633504

[sfdownhill]

Thanks raYzerman - if the harness matches the ECU in that ad, it’s a 98/99 harness like the ones we already have. In the US, 5 gen ECUs w part numbers ending in 671 (49 state) and 771 (California) are all 98/99. I’ll check with the seller.

[Cogswell]

 

Wow - those types of problems really are a be-otch.      By replacing the entire harness you may unknowingly address whatever the issue is, ground, or otherwise.  That is, by pulling connectors apart and removing grounds you might distrub whatever corrosion is causing the issue and it may appear that the new harness fixed it when in reality it might have been that the replacement process ended up identifying the problem vs a new harness.  Given that you were smelling something hot when this happened might indicate some high resistance in a circuit vs a bad ECU, though the latter could be an innocent bystander in the electrical shootout.  Anyway, one of my maintenance practices which I've fallen behind on has been about every 3 years to separate every connector on the bike and using a flat toothpick treat every pin on each connector with Oxgard.  Since by replacing the harness you'd be doing much the same anyway, going through end to end methodically to do that might be one way of finding the gremlin.  Grum's certainly on to something with the main fuse - it sure seems common.  Best for getting this sorted out - please share with us when you get to the bottom of it. 

[Grum]

Hi Lance.

Just some advice before going to the inconvenience and expense of replacing your ECM. re your classified add for one.

 

It's absolutely vital you thoroughly verify Power and Grounds for the ECM to be solid. Measuring at the plugs of the ECM wiring side you want to be sure you have a good 12v at B8 Black/White wire with Ignition to On. Grounds on B1, A9 and A20 should have solid continuity back to the Battery Negative terminal, not just frame. (You will need a correct wiring diagram for your bike to verify the above, grounds and power are from a 5gen drawing I have.)

 

The Grounding output from the ECM to the FCR should be checked for the 2 to 3 secs interval at switch on.

Wiring, poor connections, faulty relays and their socket connections, bank angle sensor, ignition switch, kill switch, common ground block, etc. can all effect the ECM power, and operation of the fuel pump. And that's not to mention the ignition enable/disable function!

Its not until checking all of the above before concluding the ECM might! Be faulty.

 

The biggest killer for an ECM is overvoltage caused by a faulty R/R. So if you get the engine running always verify the charging system.

 

While there is no doubt the ECM is the most complex device on your bike, it also happens to be one of the most reliable devices!

Far more often than not is all the peripheral "stuff" hanging off the ECM that is at fault not the ECM itself.

 

Good luck.

[sfdownhill]

Thanks Grum and Cogswell! I’ll incorporate your suggestions as we proceed with fact-checking.

 

BTW, the current ECU in the problem bike is the good A01 from the bunch of four ECUs we used to test. I pulled the good A01 from another 2001 and so am shopping for an ECU to replace it. The ‘bad’ A01 may deserve another round of testing on the other non-problematic 5 gen.

[RC1237V]

Hey Lance, 

 

     Had a similar issue many years ago on a car, after hours of diagnosing and head scratching, we replaced the engine harness and it solved the problem. I kept the bad harness and would look at it in my free time. Eventually I found the problem, that the fuel injector wire insulation had cracked a bit showing tiny spots of bare wire, I could only see under magnification. Not sure if they shorted to each other, or to a ground on the vehicle, but it shut the car off, and would not re-start. Many towing bills, but it would start the next morning, and run fine until heat/vibration etc would short it out again.

 

I hope the new harness solves the issue, as those intermittent shorts are hard to find.

.

Keep the old one for forensic analysis when you're bored...😅

[DannoXYZ]

This is not ground problem, but short!

One test to do is measure resistance of every power-wire to chassis ground with bike off. Such as power-line to injectors and coils. All should have no connection/infinite resistance to ground. Any circuit with short should be traced from component back to battery.

 

If fuse-B is blown, don't just replace it, you'll burn up even more of what you've been smelling. Find that short! Start 1st by measuring resistance on exit side of fuse-B wiring to ground. Most likely you'll find it's connected.

 

Does backlighting for dash work? Pull and measure resistance across legs of fuse-G. Also measure resistance-to-ground of brown-blue wire coming out of fuse-G.  You can do that with fuse pulled and putting one probe to chassis-ground and other to connectors fuse pushes into.

[sfdownhill]

Thanks RC1237V and DannoXYZ! We will incorporate both your wise words as we undertake the hopefully-final trouble shooting and possibly harness swap this weekend.

 

I found a clean looking harness from a 2000 VFR and have it on the way. 
 

Forensic examination of the old harness is definitely in order. We’ll have CSIVFR do the lab work.

[DannoXYZ]

FunTrackDayz does put on great event. I also miss Z2's Sat. night parties and Luau pig-roast!

[sfdownhill]

1 hour ago, DannoXYZ said:

FunTrackDayz does put on great event. I also miss Z2's Sat. night parties and Luau pig-roast!

 

At the FunTrackDayz event last week, Duc2V4 and I were cracking up at the way the announcer on the PA would add a hooting "HOOOWEEEE!" after every grid announcement.

[bmart]

Attention getter!

[sfdownhill]

21 minutes ago, bmart said:

Attention getter!

 

Too much of an attention getter! I did a good job of installing the awesome 847 reg/rect and thought I'd be able to sit on the sidelines eating popcorn while watching all the other electrical gremlins get chased by other guys...

[bmart]

I assure you...other guys are chasing!

[vfrcapn]

Good luck getting it sorted.

 

And, damn nice wheels!

[sfdownhill]

22 hours ago, vfrcapn said:

Good luck getting it sorted.

 

And, damn nice wheels!

Thanks capn - once we get the electrical sorted, Ill gather all the photos and write up the mods.

[sfdownhill]

Quick update to demonstrate that I’m not one of those guys who posts up a big conundrum then vanishes.

 

We installed an all-new used wiring harness and a VFRness subharness to beef-up the vulnerable main fuse circuit.

 

This solved the electrical problem  and the bike is running great on the dyno and the street/freeway, though only James has ridden it - I won’t get to ride it until a friend of James’s brings it out to the track this weekend.

 

The dyno chart is off-topic for this electrical thread, but I’ll include it, just cuz. The bike did one hp less on the recent dyno pulls than it did on the Attack Performance dyno in 2019, but we’ve come to learn that the Attack dyno is notoriously generous. And why not? It’s gotta be good for business to have a dyno that skews a little high.

[bmart]

Usable power is so much more important than peak power. 

[sfdownhill]

1 hour ago, bmart said:

Usable power is so much more important than peak power. 

 

Agreed - I will reserve judgement until I get a chance to ride it, but am very happy with the appearance of the torque curve.

[ducnut]

Stuff like this is why I completely stripped my harness, when I disassembled my 5th Gen. I saw some random burn marks, so I knew there’d been a previous charging system issue and just didn’t trust the harness. I have guarded peace of mind, now. 😁