Hi, Sorry if this is to long below. I'm having a few issues with my SVO. I have a 84 mustang SVO, It has the 2.3l turbo motor. It has a misfire at idle. It also misfires when you rev it to 3500rpm or 4000rpm. it goes lean and back to rich on the Air/fuel gauge when it misfires. Its a random misfire. I tested the injector waveform with a scope and when it misfires it appears to drop on the waveform and return to normal randomly.
I can hear it misfiring/small popping in the exhaust at idle. the rpm moves up and down sometimes too. Any ideas?
I have good spark plugs and good wires. new cap and rotor and newer ford distributor.
My mechanic buddy thinks its either I have weak injector driver transistors in the ECM or it could be my injectors being to big since I have 35lbs brown top injectors instead of the 30lbs green top injectors that came in the 84-85 mustang SVO's. Could that be why I have a misfire? The inectors being the wrong pound injectors for that ECM? Causing the ECM injector driver transistors to slightly overload?
The injectors in this car are triggered by a ground circuit to open and close the injectors and they are batch fired.
My buddy thinks the injectors are spraying to much fuel which is causing it to go rich then the ecm trys to compensate for the rich condition and makes it go lean.
My ECM is the ZBA code.
The puse width on the scope says it is running at about 1.4 milliseconds to 1.7 milliseconds injector pulse on time. Not sure if that's where it should be or not.
Is the 84 computer compatible with the 35lbs injectors without modification?
The SVO's in 1984-1985 came with 30lbs injectors which where green top low impedance injectors.
The injectors that currently are in the car are 35lbs brown top injectors and they have 2.9ohms of resistance each when I test them individually with an ohm meter. Which are low impedance injectors.
I took the injectors out and used my custom made fuel rail and injector pulser to test the flow of the injectors each and they all seemed to flow good.
When I drive the car it doesn't have that much take off from the stoplight/bottom end but has a bunch of power on the top end when the turbo is kicking in. I'm wondering if this misfire would cause this?
Sounds like timing to me but the timing seems to be fine when I check it both cam timing and distributor timing which distributor timing is set at 10* Before TDC with spout disconnected.
Any help would be a big help. Been messing with this car for a while now and cant seem to pin point the issue.
Thanks
Jeff
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