Another strange engine failure

I was banked over on a right hand bend recently when the engine just suddenly died. Coasted to a halt safely. With ignition switched on all lights etc worked but the ignition and fuel pump didn't. No flashes from the malfunction indicator light. Turned out the ignition/fuel pump circuit fuse had blown.

Replaced that with a spare and got home. Few days later heading out again, few miles from home, same thing. Popped in another spare and turned back for home. On the way back the ignition repeatedly momentarily cut out and restarted, with the HSS light coming on each time.

Could this indicate a regulator or rectifier fault? Can anyone help me where to start looking? Obviously I can't just keep changing fuses!

Cheers

BTW machine is a 2010 UK spec SWing with 14000 miles.

Considering the age of the machine, I would look for a frayed wire. This when hitting a ground can pop the fuse. Easiest thing to check too! Good luck.

I agree with Glenn's "frayed wire" idea. Check that blown-fuse circuit in the wiring diagram of your FSM to see what else might be on that circuit. However, given that it's the Ignition/Fuel Pump fuse which is failing, I'd take a close look at the ignition switch wiring.

Chances are that the short circuit will be in the wiring from the ignition switch forward (around the steering stem and to the Combination Meter). Not exactly easy to trace because you pretty much have to remove the entire Front Cover and Inner Cover/Floor Upper then reconnect the Combination Meter and start wiggling wires.

Tim

Update: I checked the wiring of the starter button and stop/start switch, all seems sound to me. Romoved the front cover (what a rigmarole!) and visually checked all the wiring I could get at. I set about jiggling wires and connectors when the engine was running hoping for the faukt to recurr. Nothing.

I found a bunch of wires pressed hard up against a frame member and two of them had slightly worn insulation but did not appear to be worn through to the bare wire. I applied some tape as best I could in the confined space.

Removed the underseat cover and did the same close inspection and wire jiggling, again no joy. removed left side cover and did the same. Nothing, until I lightly pushed on the black plug of the ECM, as illustrated. Then the engine sputtered and regained then sputtered and died when I pushed again. No fuse blown though but the MIL did flash with a code for No1 Fuel Injector. I repeated this test several times and it really only seemed to require light pressure or a slight jiggle of the plug at it's training edge to induce engine failure. Jiggling the wiring leading into/out of it had NO effect, just jiggling the body of the plug.

I unseated and reseated the plug carefully several times but no difference. Any further help will be appreciated.

Is your finger pressing on the wires which cause the malfunction? What is the color of that wire, or wires? It seems to me that you having disconnected/reconnected that black terminal with no positive results would eliminate a terminal connection failure. So maybe the problem is the wire connection to the terminal itself. Perhaps the wire harness itself is too strained and has caused stress breaks at that wire-to-terminal connection.

I am sorry that I don't have access to my scoot so that I could see how those terminals can be removed from the plug body. It may be that you'll have to remove those terminals and splice in some new wire pieces to eliminate the stressed pieces.

Tim

Sounds like you have a loose connection on that connector. It's not uncommon to get a crimped wire connection to loosen up due to the vibration and hot/cold cycling during use. A magnifying glass is a good tool, look closely at the wires in the area for signs of black or copper dust or green corrosion. You could try soldering that wire. It would be necessary to disconnect the connector and then work the insulation back slightly by warming up the insulation and slipping it back to expose the wire. Then just lightly tin the wire with solder, not enough to run down and foul the connecting point, just enough to ensure good connection between the wire and the connector.

Thanks Gents. Firstly, no my wife's finger is not pushing on any wires but indicating the area of the plug body that I pushed. Jiggling the wires going into the plug did not cause any malfunction, only pushing (lightly) and jiggling the plug body.

I'll not attempt the suggested soldering, thanks. I utterly lack the skills required! I plan to take her out on a test run on very local roads to see if the problem recurrs after my examination. I have stocked planty of spare fuses in case so I shouldn't get stranded! Looks like a visit to my friendly local bike mechanic will be required!

You may be looking at a ECU problem where connector is soldered to cpu Pcb.
As a test Try replacing fuse with next size up. It may be excess current and not necessarily a short. Hopefully a dealer can see a diagnostic code.

Bob

Up sizing the fuse may cause one to let the smoke out of the wiring, normally when that happens you end up replacing the wires which can be $$$$$$$$$$$$ sive and time consuming Better off finding the root cause of the problem. JMHO

You might try pulling the harness plugs and using Contact Cleaner with a non-metalic brush on both the wire harness plug terminals and the ECU terminals.

The ECU is easy to remove from the mount once the wire harness plugs are removed. The rubber mount just pulls off the tabs. That will allow you to inspect the ECU terminals up close for any corrosion or other problems.

Tim

I concur with oldwingguy. Fuse sizes are determined by wire size not what's connected to the wires. The whole idea is to prevent fires caused by too much current in the wiring, not to protect whatever is on the far end. Oversizing fuses can indeed mean you might have to buy a smoke kit to refill the system.

If I may, it's a guaranteed blowup in your face basically to up size fuses to let the smoke out, remember it's faster then the fuse and it may also be doing some damage in other places...not just the wiring....

Well, finally got to the bottom of it last week. Took it to a recommended independent alleged electrics wizard. Explained everything and even he looked stumped! I checked a week later and he had the bike in bits chasing ghosts! However, he did track it down to the very same area of wiring that had given trouble last June, when the symptoms thrown up were faulty fuel injectors.

On that occassion Honda told me they found some wiring that had been unduly worn under the seat area and they had repaired and re-routed the wiring. My independent found the wiring had been repaired  but had not been re-routed but left lying across the fuel rail, being once again damaged under the seat and causing short circuits. See attached pictures. This was the one area I had not dug into on my explorations!



So, wiring fixed again and it's positioning taken care of and my Buzz Bomb flies again! Mt Honda will be receiving an unhappy letter. Might be worth other SWing pilots having this wiring looked at.

Cheers

Martyn

Thanks for the update Martyn.
It does concern me the way wiring looms are often 'crammed' into tight spaces without sufficient wiring length to allow for a bit of slack which would reduce stress and strain.

It's not just Honda - they all seem to do it.

I will certainly be checking that area the next time the covers are off my bike.

Thanks again - often on forums members will report problems but never come back with the solution.

Wires are also getting much thinner these days, I have just re connected my Garmin, the conductor was almost like a hair. I suspect the wire would melt before the fuse blew !

Martyn, Thank you for following up with the solution to this mystery. And a special thank you for including the photos. Now we all have some thing to closely inspect when we next have the undercover off.

Why on earth would a manufacturer ever route a wire harness over a fuel rail or any fuel line? Seem as if that is only inviting disaster.

Tim

Cosmic_Jumper wrote:

Martyn, Thank you for following up with the solution to this mystery. And a special thank you for including the photos. Now we all have some thing to closely inspect when we next have the undercover off.

Why on earth would a manufacturer ever route a wire harness over a fuel rail or any fuel line? Seem as if that is only inviting disaster.

Tim

There are many why's on different products, sometimes I think it's just a matter of the person assembling things at that time. Good friend who was final QA for KW trucks, what the hello were they thinking when they did THAT many times they weren't.

Congratulations on the fix Martyn ! Should be a more relaxing (stress free) season ahead for you. Threads like yours are what makes this such a great, helpful and informative site ... especially when the mystery is solved and the solution made known - as you have done. Thanks for this from me too.

As an aside .... In '97 I visited NI with some friends. Sheleven House in Bangor was our base and tours to Carrickfergus, Belfast, Bushmills, Portaferry and Daft Eddy's are clear in my memory. It was a great time.

Mike

Hi Mike, glad to help as others here have helped me and glad you enjoyed your wee tour of my wee country! Sheleven Guest House is just a bit down the road from me in Bangor By The Sea! I'm sure you found a number of parallels with Nova Scotia. I've visited Canada many times, driven across it in a Greyhound in 1984! Hope to visit NS in the next few years, maybe ship my SilverWing over and tour about!

Cheers
M