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ECU? Don’t know where to start. Looking for help.

273 Views 10 Replies 5 Participants Last post by  Jesinator, 
jdiz86
I’m at a bit of a loss. I was having issues with my pulling power last fall. Power to the bike would cut off at certain rpm. I since have readjusted the TPS and STPS, and had my STVA tested. Also had my fuel pump tested, tried bypassing kickstand switch. All are good and in spec.

I finally throw plates on the bike and took it out for its first rip of the year. All was good for the first 10 min but I was taking it easy. When I really opened it up, it bucked at around 6k rpm in second gear off the line. The same power cut I experienced in the fall before storing it over winter.

I pulled into a parking lot to think a bit, then as I pulled out, as I transitioned from curb to road the bike stalled. I get an FI light, and ‘CHEC’ on the dash. Maybe that’s normal given it’s on but not running. Anyway, bike now won’t turn over, but there’s power. I push it home. Luckily I’m only a few blocks away.

When I get home I throw it in dealer mode, no code shows up. Just “-C00”. Now it starts up fine. Like what the hell.

Why would my bike stall after a little bump (curb) and then not start up, to then start up 15 min later? Non-pump related fuel issue? Why would the FI light come on then vanish? Why is it bucking/cutting power? Could my ECU be causing these issues? Faulty TP sensors? Not sure where to start.
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B
First question, do you have a power commander on it?

Secondly codes are not stored so if the bike is shut off the current codes disappear.

I would check all the connectors, even the ones under the tank. Pull them apart and inspect them. Pack them with dialectic grease before you plug them back in.
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B
Low oil pressure will turn the red LED on so you'll get it when the ignition is on but the engine isn't running. But you'll also see an oil can icon appear. CHEC means that the cluster isn't receiving data from the ECM, typically because the ignition is on but the kill switch is off. SDS can retrieve cleared codes but few have it. How was the fuel pump tested? You need a flow test, not a pressure test. Balking as the revs go up is normally either a clogged fuel pump main filter or a secondary throttle issue. The bike not turning over is commonly a low battery issue, i.e. the charging system isn't doing its job or you've let it sit with the lights on.
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jdiz86
boostenlebaron said:
First question, do you have a power commander on it?

Secondly codes are not stored so if the bike is shut off the current codes disappear.

I would check all the connectors, even the ones under the tank. Pull them apart and inspect them. Pack them with dialectic grease before you plug them back in.
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jdiz86
boostenlebaron said:
First question, do you have a power commander on it?

Secondly codes are not stored so if the bike is shut off the current codes disappear.

I would check all the connectors, even the ones under the tank. Pull them apart and inspect them. Pack them with dialectic grease before you plug them back in.
Click to expand...
Yes, I do have a PCIII, and haven't touched it since buying the bike last year.

I guess I will take my dealer mode switch with me in case that happens again so I can pick up a code if it's actually throwing one.

When you say connectors, what do you mean? ECU? all plugs everywhere, like to injectors etc? Am I looking for burns or dirt or something?
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jdiz86
BillV said:
Low oil pressure will turn the red LED on so you'll get it when the ignition is on but the engine isn't running. But you'll also see an oil can icon appear. CHEC means that the cluster isn't receiving data from the ECM, typically because the ignition is on but the kill switch is off. SDS can retrieve cleared codes but few have it. How was the fuel pump tested? You need a flow test, not a pressure test. Balking as the revs go up is normally either a clogged fuel pump main filter or a secondary throttle issue. The bike not turning over is commonly a low battery issue, i.e. the charging system isn't doing its job or you've let it sit with the lights on.
Click to expand...
Thanks for this.

Ya, maybe there wasn't a true FI. Maybe I accidentally hit the kill switch (doubtful), or maybe my new kickstand switch faulted (recently replaced the old one I spliced when trouble shooting last year).

Fuel pump was tested via flow test. Shop did it. They said it was fine, then adjusted the TPS (or STPS... didn't confirm at the time because was not knowledgable), which really improved performance; seemed allow me to near redline the bike. It still bucked, but at around 11-12k rpm vs around 6 k rpm like it's doing again now. Maybe I recalibrated the STPS incorrectly. I did not go by the manual spec of 0.57-0.67 and instead went with 0.5 ohms, as recommend in the guide from TheGeek. I locked in both TPSs correctly, at least I think.

There shouldn't be a problem with power because I just recharged my battery. Could test it again, I suppose.

Bike is a k7 btw.
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Engenia
Had something very similar happen a few months ago with my Tornado. Bike would start and run for a bit than wouldn't make power and eventually stall.
I changed the fuel filter - not that.
Removed the fuel pump & tested the pump flow, and pressure. Then tested the regulator. All fine.
Ended up being the wiring to the pump. A high resistance connection that got worse as it heated up. When cold, the pump would start but seen cut out.
Solution described HERE.
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B
Pull the power commander off before you do anything else. See if it fixes the problem.
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jdiz86
boostenlebaron said:
Pull the power commander off before you do anything else. See if it fixes the problem.
Click to expand...
Just did that. Same issue. Runs fine if cruising half throttle. Anything more and up to 10k rpm and it sputters. More diagnosing to do. Might get fuel flow test done again but longer. This was recommended to me.

I’ve come across other posts that have solved similar issue by replacing injectors, TPS, plugs, or fuel pump (regulator).
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B
How do your plugs look? Maybe just put new ones in to be sure.
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Jesinator
I fix odd issues like this all the time and feel the need to represent the idea of using all provided tools before asking for help: read the factory service manual. They are available for $17-ish dollars in pdf. Go straight to the FI diagnosis section and find your symptoms. I have had incredible ‘luck’ following those steps exactly for numerous bikes and I have a 100% success rate at finding and repairing the issue thanks to the manuals. This may lead you to finding or realizing it was a couple small problems or one big one. This will also teach you about your motorcycle; win-win! Speculation will only waste time and money.

Some clarification:

Are you having electrical loss of power during the bucking or just mechanical loss of power?

It was unclear to me: are you currently “no crank, no start”, or “crank, no start”?

Your ECU does store codes. Straight from the manual: "Before checking the malfunction code, do not disconnect the ECM lead wire couplers. If the couplers from the ECM are disconnected, the malfunction code memory is erased and the malfunction code can not be checked." Previously stated on the same page: "The defective function is memorized in the computer. Use the special tool’s coupler to connect to the dealer mode coupler. The memorized malfunction code is displayed on LCD (DISPLAY) panel. Malfunction means that the ECM does not receive signal from the devices. These affected devices are indicated in the code form." Notice the key word memorized, meaning permanently stored (until cleared).

Here is the diagnosis sheet for the symptoms closest to what you have described.

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