The pcm controls the coil activity. The quad driver in the pcm may have failed.
Have the wiring checked from coils back to pdm before asuming the pcm is bad
February, 16, 2013 AT 5:58 PM
The PCM was replaced, due to no reference signal to cam sensor, there is spark at cyls 1 & 3, when you change coils, it still has spark at 1 & 3, so I think coils are good, Chain timing marks are right, compression is 210lbs. On all cyls, when cranking it backfires.2
February, 16, 2013 AT 6:03 PM
Checked wiring from cam sensor to PCM, had continuity
February, 17, 2013 AT 4:16 AM
Your question states cylinder # 3 & # 4 has no sparks but later you indicated # 1 and # 3 has sparks. I need to clarify this.
Which transmission do you have, 3 or 4 speed auto or manual?
Were the wirings checked for continuity between the PCM and ignition coils?
Were the ground wires for the connector checked for continuity to ground?
Is it confirmed that sparks is missing and not fuel injector problem?
February, 17, 2013 AT 2:59 PM
Sorry about confusion, cyls 1 & 3 have spark, cyls 2 & 4 have no spark, switching coils makes no difference, so coils are good, Should I have 5v reference signal at Cam Pos. Sensor w/key on?I have no voltage @ cam sensor with key on. When I disconnect wiring to sensor and check w/ohmeter, I see varing resistance as engine cranks. Have not yet checked continuity between coils & ECM or coils & grnd, will do now. Have checked continuity between cam sensor & ECM, (has good continuity)
Car has a 4 spd auto, I have confirmed no spark @ 2 & 4 and good spark @ 1 & 2
I sent ECM to "EAS" in Jax, Fl, they said ECM was unrebuildable, do to no signal to crank & cam sensors and built a new one, it is doing the same thing. Also has a new Crank pos. Sensor
February, 18, 2013 AT 12:50 AM
Symptom indicates a fault between the ECM and ignition coil rather than anything else.
If it is a Crank sensor problem, you would be getting no sparks. How ever having only 3 sparks could be a fault with the picku points of the sensor rather then the sensor itself but this would throw trouble codes.
I have attached a schematic of the ignition coils.
Attach a noid light to terminal # 3 of the coil and ground the other end. Crank engine and note if it pulses.