Injector Signal Issue

Discussion and support for MoTeC's previous generation ECUs.

Injector Signal Issue

Postby apiazza2010 on Mon Mar 25, 2019 7:36 am

Hello All,

I have been puzzle with an issues as we have reassembled the powertrain system of the car.

This is a previously working harness and engine combination.

Engine: CBR600RR
Ignition: Bosch 4 channel igniter on stock COP
Fuel: Stock 210cc Injectors
Fuel Pressure: 60 PSI
Motec M400

The engine is not starting, crank but no start.
No fuel in the intake or on the spark plugs.
Trying to troubleshoot, I did the following.

1. Check for REF/SYNC problems, the ecu goes in Synchronized OK
2. Check for Spark by grounding a plug and COP outside, OK
3. Check voltage at injector, 12V on ON, a little less than 10V on Crank
4. I noticed that the injector are triggered LOW from the ECU even when not cranking. Is this normal?
As In when i hook up the multimeter to the + and - at the injector. I see 12V. I assume this is the self check of the motec?

5. I run the TEST OUTPUT on the injectors, they all work fine, i can hear them and hooked up an ocilloscope and this is what i see:

Image

6. If i hook up the oscilloscope while cranking, this is what i see:

Image

I think there is a tremendous amount of noise in the signal,
So i re-routed the grounds to another area, no good.
I tried to move the starter away but i'm still puzzle.

Do you guys have any suggestions?
apiazza2010
 
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Re: Injector Signal Issue

Postby David Ferguson on Mon Mar 25, 2019 10:10 am

Check for voltage drops in your starter wiring. Could be the wire, terminal, or the starter itself.

I doubt that is your no-start issue. Has this ECU/engine combination been running previously, or is this your first attempt to start.

If it cranks but doesn't fire, first check the timing, and verify the CrIP set correctly? Always worth trying +360 (or -360) in case the cams were installed 180 deg out.

If the Timing is good, and you've indicated you are seeing spark, then I would increase the fuel (by changing the injector scaling, IJPU found in Adjust->General Setup->Fuel->Setup, go up 10-20% at a time until something happens.

I don't think the injectors outputs are driven low when not running, but they will read 0V if they are not connected to a powered injector. Try back-probing the connection with an injector connected.
David Ferguson
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David Ferguson
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