Loss of all electrical power at 10,000 RPM

[Briggs09hp]

Hello,

We just got our car running last weekend and we are trying to work all of the bugs out of the car before we leave for competition. I am running into a very strange situation. When I rev the engine to 10,000 RPM, the entire car shuts down electrically for a very brief moment, and then comes on immediately once the RPM's decrease. The engine will not rev above 10,000 RPM. It is as though there is a rev limiter acting on the engine. I have checked our rev limiter on our MSD (DIS-4) and our ECU (Autronic SM-2) and they are both set for 12,000 RPM. But even if it were a rev limiter, it would not cut power to the entire car. I have tried installing 2 separate MSD's. I have tried 2 separate ECU's. I have the engine block grounded with a ground strap. I thought I might be pulling too much electrical power with all of our electronics, including 2 fans, fuel pump, wide band O2, gauges, etc. so I disconnected everything except what is necessary to run the motor thinking that when the engine speed increases, it requires more power to run so I should minimize power consumption, and it still does it. This one has me stumped. The car runs great up until 10,000 RPM, but after that it backfires and cuts out and comes back on once you let of the gas to decrease the revs. It is a completely stock 2001 Honda CBR600 F4i. We are running the stock cam and crank sensors.

This is the same wiring system we have been using for years (meaning I make the same wiring harness every year), and I have never had a problem like this. Tomorrow i will closely examine the wiring harness to make sure everything is tight and there are no shorts or pinched wires.

Does anyone have any idea what might cause this?

Thanks,

Matt

[TMichaels]

Possibly a problem with the rectifier/alternator? Try changing both, if possible. Or disconnect the rectifier and see what happens. Usually you need to connect a bigger battery to be able to do so.

Otherwise hook up an oscilloscope to the 12V supply line of your ECU and see, what it does, when reaching 10,000RPM. If the voltage breaks down very deep, you have a basic electric problem. If not, it should be a setup problem.

Another thing which might be worth checking is the dwell time setting of the ignition coils. Maybe you forgot to fill the table completely?

If all of the above measures do not help hook up the scope to one of the ignition outputs of your ECU and to one of the injection valve outputs and see, if the ECU cuts ignition or fuel while beeing supplied with stable(!) 12V. (See test above). Should be done anyway. If the ECU cuts one or both while having a stable supply it definitely is a setup problem in your ECU or a problem with the connected sensors-> Have a look at the sensor readings while reving up.

Edit: While reading your post again, it is not likely that, with changed parameters, the error still occurs exactly at 10,000RPM, if it is an electrical problem. I would check the settings in your ECU again.

Regards,

Tobias

[BuckeyeEngines]

I agree with Tobias, Check your stator. Put a volt meter on the battery while the engine is running, is it 14 volts or so? I have scratched my head for a while over what turned out to be a bad voltage regulator.

[Briggs09hp]

I did try to disconnect the rectifier last night thinking it might be the problem. This did not help. The rectifier is brand new. However, now that you say that, I did accidentally hook up the battery backwards while the engine was on the dyno. The rectifier is new since then, but the internals (stator) were not changed. But disconnecting it should eliminate that as an option wouldn't it?

Do you think it could be the cam and crank sensors? I am pretty sure the stock cam and crank sensors on the F4i are reluctor sensors. The Autronic ECU cannot read reluctor sensors so they sell an interface box that converts them to hall effect style. There are two wires for the cam sensor and two wires for the crank.

Does it matter how I hook up the sensors? Let me explain this question using an example: Our cam sensor has a white wire and a gray wire. The reluctor interface box that wires the cam sensor to the ECU has a black and red wire. Does it matter which way I wire those two wires together? Can I wire the gray cam wire to either of the red or black wires, or are the sensors directional?

I have tried wiring the cam sensor both ways and the engine runs either way, but it still does it.

It is very strange that it happens at the same RPM every time.

Can you explain a little more what you mean by the dwell time? Our timing map is just a spread sheet with RPM on X axis and engine load on Y axis.

Also could you explain what you mean by a basic electric problem, and setup problem?

Thanks alot for your help,

Matt

[BuckeyeEngines]

you do not want to disconnect the rectifier, you want to make sure that you are running on 14 volts. The injectors and ignition system is designed to run on 14 volts, when it runs on 12 volts(if the stator is not putting current into the battery) it will idle, rev some but will not achevie high rpm. So when you have it running at idle check your voltage at the battery. If it is not above 13 you need to figure out why your charging system is not working.

Dwell time for coils is how long the coil will charge before it fires. This should be a setting in your ecu. If you have it set to charge for too long then once you reach a higher rpm where it is firing more frequently it will not fire properly.

[Briggs09hp]

Well, I feel stupid saying this but it seems like it was just a loose master power switch (push pull). At 10500 RPM the car vibrates alot, so the switch was loose and the wires were joggling out.

Lesson learned, always start simple.

Thanks for your help, even though we thought it was way more complicated.

Matt

[TMichaels]

Otherwise hook up an oscilloscope to the 12V supply line of your ECU and see, what it does, when reaching 10,000RPM. If the voltage breaks down very deep, you have a basic electric problem.

This test would have revealed it and this is indeed a basic electric problem, isn't it?

Regards,

Tobias