I have done all the service manual checks, replaced ECU and ignition pulse generator., checked relays, switches etc. Can't find anything wrong. I have read about the pink wire issue with the ignition switch so I checked it. I am getting 9.9 to 10 volts at the pink wire with headlights removed, fuel pump disconnected and ignition on. I have heard that anything over nine volts is a problem, how exact of an ECU tolerance is that ? Would 9.9 be too much or is my reading of it due to the less drain of the headlights and fuel pump. The switch has a plastic cover on the bottom with torx screws smaller than anything I have so trying to fix it may be problematic and new OEM switches seems unavailable. Any help or thoughts would be greatly appreciated.
Thanks, Stan

 

Does fuel-pump prime for 3-sec when you turn key ON and start/stop=RUN? If so, forget ECU, ignition-switch & pink wire, relays, BAS, pulse generator, all those are perfectly fine. Don't replace perfectly-working parts with brand-new perfectly working parts because nothing will change.

Need to positively and absolutely 100% identify exact cause of your problem through measuring and testing where numbers implicate issue. Most of time, 99.99% of time, ALL parts are perfectly fine. Issue is caused by corroded terminals, or disconnected plugs or bad broken wiring.

Here's 1 of only 2 things that matter in no-start condition at this point:

1. key ON, start/stop=RUN, measure voltage at each ignition-coil connector. Volts1=??? ... volts8=???

2. as verification, measure voltage at each injector connector. volts1=??? .... volts16=???

 

For example, guy brought in non-starting bike to my shoppe, after replacing everything in entire EFI system. From battery, fusebox, relays, ECU all way down to all injectors and ignition coils. Even replaced every single light-bulb on bike and also dash. Only thing he had left was harness and replaced that with eBay item as well. It still won't start, gave up and brought it to me.

First mistake was not buying factory OEM parts from authorised Honda dealer. So many low-quality countrefeit parts from 3rd-party suppliers. Many are bad right out of box. Every single one of them needs to be measured and tested to confirm functionality before using. Otherwise additional 3,4,5 or more errors will have been introduced into system on top of original fault. Had him put ALL original OEM parts back on bike. Except for replacement harness since that was OEM as well.

Then I measured for power at endpoints: injectors & coils, which tests entire chain from battery on down and everything in between. Problem was single broken wire in harness! Fixed it bike started right up! Probably took all of 10-minutes...



Unless you are Superman and can see electrons moving inside wires, no human can just look at wire and determine its ability to conduct electricity. Luckily, we have instruments that can.

 

Thanks for the reply Dannoxyz. When the bike quit I recall the fuel pump priming as normal and It seemed at the time It was a spark problem, so I focused on running all the ignition test per the service manual, relays, clutch, sidestand etc. The tank has been off all this time, I will go out and reconnect it and go through the tests to see if it primes and check the injector voltages. As far as I could tell the ECU only needed to see the ignition pulse generator, coil voltages, relays, etc. for a spark. I have seen some people mention that the ECU needs to see the injectors and fuel pump before triggering a spark. Is that so ?

 

Nah. ECU doesn't care that pump, injectors or coils are even connected, it'll still fire them independently. Might throw code about bad injectors or coils later, but will still fire them.

What's history behind bike?
When was last time it ran perfectly?
What happened between then and now?


Put all original OEM parts back on. If you swap part and that doesn't fix problem, then part wasn't bad and cause of issue. So immediately put original back on. Otherwise you've introduced additional unknown variable and may have added fault into system.

3. unplug ECU. Stick small brad-nail or paper-clip into terminal of grn/wht wire. Measure resistance between grn/wht terminal to chassis-ground. ohms=??

 

The bike has been flawless since I bought it 12 years ago. I have been working on bikes since the late 60's, road raced in the 70's and in 1990 with the WSMC. All my bikes are prepped before every ride, they all spend their time in the Tahoe National forest exclusively since being purchased and ridden home to Foresthill. It ran perfectly on the last canyon ride last summer before we were evacuated due to a fire. My youngest son wanted to go for a ride several months ago, geared up and we left the garage, he hit the starter and it cranked fine but wouldn't fire.
It was priming but seemed like there was no spark. I suspected the old battery at first even though its always on a tender and have never had any problems. I did remember reading forum posts many years ago about people having problems of the sort with their 954's but didn't expect it with mine as I have put over 16k on it since buying it and it has been reliable as a rock. Had been planning on doing the 32k valve clearance check until this. Will do after I get it running. It has been sitting in the garage for awhile as I just haven't felt like going over it again.

The green white terminal (on the grey block)has under 2 ohms resistance to ground when disconnected. I put my original ECU back in as you suggested. The coils have 12 volts, yellow wire ~.7 volts on cranking, ignition pulse generator ~.7 volts. clutch, kickstand, stop relays all check out. My second son is an electrician and we have gone over it with both mine and his multimeter. I'm sure I have missed something probably due to frustration, likely a simple fix that I have missed.

 

Ok, if your pump primes Ok, we're down to very few things that may be wrong.

1. resistance-to-ground on grn/wht is final result of safety-interloc OR circuit with clutch, neutral and sidestand circuits. Clean all terminals on these switches along with other ends of wire and clutch diode. As troubleshooting step, connect grn/wht terminal directly to chassis ground. Do you get spark now?

2. pink security wire @ 9.9v from ignition-switch being too high should also disable pump prime as well. Attach 50-ohm 1/4w resistor in-line/series on that wire and see if you can lower voltage to less than 9.0v. Increase resistance until you get just less than 9.0v Do you get spark now?

3. was cams ever out for valve-adjustment between when it was working and not? Trigger wheel for cam can get bent out of position. It'll still generate minimum pulse 0.7v, but timing will be off. ECU won't trigger spark. No easy way to check timing without oscilloscope. Can always take cam out to look

 

Thanks for the ideas. I will get a resistor to test getting the pink wire down to under 9 volts and will ground the green/white wire to test for spark also. I appreciate your help, will let you know the results when finished.

 

Here's what bent cam-trigger wheel looks like. Extremely easy to put cams down on bench and bend them.



Shifts cam-trigger timing relative to CKP signal and ECU's confused.



Also jumper DLC diag port to have it flash error-codes. Anything show up?

 

At the moment only error codes are due to the fuel system not being on the bike. When I do the valves I will keep your advice in mind, fortunately had no issues 11 years ago when I did them. Got my resistor pack today will work on the pink wire tomorrow, hope it fixes it.