Cylinders 2&3 not firing out of coil, coil packs good, possible cam sensor ?

[ShadeTreeDSM]

was driving to a friends house yesterday and was cruising about 80mph and all of the sudden the engine started running like crap. pulled over to gas station and knew it had missing cylinders. popped hood and had car running. pulled each spark plug wire off while running. if i pulled cylinder 1 or 4 it would arc & then stall. pull 2 or 3 the car would stay running, no arcing. checked wiring and some wiring was loose, re wired it and started it, no spark. got someone to bring me a coil pack, changed it out, still no spark out of cylinders 2 & 3. ECU was just rebuilt 3 months ago. checked wiring at cam sensor and noticed the the seal on the cam sensor was leaking oil on to the cam sensor wiring, the wires were exposed and one they were touching eachother. so i rewired that also and still no spark !!! only thing that wasnt changed out is the Cam Sensor. its the original 1990 sensor. flat greenish looking one. i have a 1993 cam sensor, black hall effect type. was thinking about using that to see if it would fix the problem.

so what could it be

 

[Froyd79]

Do you have an extra transistor pack to try out? I would swap one of those in and go from there.

 

[tenn-gsx]

^^^^^^^ What he said. Swap that puppy out and your problem will probably go away.

 

[ShadeTreeDSM]

Do you have an extra transistor pack to try out? I would swap one of those in and go from there.

i wish that was the case, i tried that also, still no fire, i tested the cam sensor circuit, turns out good. Haynes manual says replace the cam sensor, thing is i just did, but that cam sensor has been sitting for about 3 yrs, maybe its bad, im goin to try another one

 

[Froyd79]

Normally a bad CAS would kill spark and fuel so the car would not run. I have gotten a CAS wet before. So if it tests out good then it most likely is.

The coil pack can do this and the transistor pack also which you said you replaced. The last thing I can think of is possibly the ECU. And sounds dumb but are you checking for spark from the wire? Maybe 2 plugs got fouled.

 

[ShadeTreeDSM]

Normally a bad CAS would kill spark and fuel so the car would not run. I have gotten a CAS wet before. So if it tests out good then it most likely is.

The coil pack can do this and the transistor pack also which you said you replaced. The last thing I can think of is possibly the ECU. And sounds dumb but are you checking for spark from the wire? Maybe 2 plugs got fouled.

i checked spark from the wire and out of a new plug.

also check RESISTANCE on the coil with an ohm meter, tests came out within specs.


ecu was just rebuilt in JAN, i would open it but it would void my warranty, also i tried to smell it for any abnormal smells, nothing out of the ordinary .

 

[heckles]

did you get the power transistor, new or used, and did you test it?

 

[ShadeTreeDSM]

did you get the power transistor, new or used, and did you test it?

its used, but came off a running vehicle.

 

[mkgearhead]

I had a coil test good on my '93 but it had a hole in the side of it and was arcing to ground. Just a thought.

 

[Colt4G63 also]

Not sure if you tried a cam sensor that you know works, but those hall effect switches can get the little windows fouled with oil, and cause all kinds of eratic firing.

 

[ShadeTreeDSM]

i ended up finding the problem, it was an open in a wire. from pin 55 on the ECU to the power transistor, so what i did was run a new wire from the ECU to the power transistor & it fixed it.