3.1 Cranks but no spark

[blk92z34getrag]

My mom's Euro won't start. It cranks nicely (well untill the battery started dying from repeated tries by her) but there's no spark.

Pulled 2, 4, and 6 wires, no spark. My dad and I put in a new Ignition Module. Still won't start. Could it be that all 3 coil packs have taken a shit? Simultaneously?

Checked fuel pressure, it's good, fuel is in the rail. Also the spark plugs look liike they should for being 30,000 miles old rapidifres, out of spec. We gapped them but it didn't help.

Any suggestions? Kinda need the car operative by Tuesday.

Thanks.

[jmgtp]

Did they all lose spark at the same time? If so, its unlikely that all the coil packs bummed out at the same time. I'd bet either the ignition module is not getting power and/or ground OR not getting the crank signal. There are 3 connectors on the ICM. The large one is for the ecm to manipulate spark and the tachometer. Then there are 2 smaller ones with two wires each. IIRC, the one on the side by itself carries the 12v and ground signal - a good starting point would be to check to see if indeed that harness is delivering power and ground when the key is in the 'run' position. If that checks out good, then the next step is to check for a crank signal. The two wire harness going into the ICM with yellow and purple wires (they may be color faded from years of heat) delivers the crank signal from the crank position sensor. While cranking the motor you can check for a signal with a digital volt meter. It should produce a low voltage AC signal. If no signal is present then either the crank position sensor has gone bad or the wiring between the CPS and the ICM has failed. The CPS is located on the bottom back side (firewall side) of the block and has a 2 wire harness that is held down by 1 bolt. Be gentle removing it because some become brittle with age and the last thing you want is half a CPS stuck in the block. Don't rule out the wiring though. I just had to run new wiring in my car from the CPS to ICM because at had failed and caused a no start condition. You could simply check for continuity on the wire using an ohm meter. If you end up replacing the wiring it is recommended that the 2 wires have at least 9 twists per foot (as stated in GM service manual) to guard the AC signal from interference.

[blk92z34getrag]

Yeah we actually checked the voltage to the ICM yesterday, it was fine (11.87 I believe) but as long as my dad hasn't already towed my mom's car to the shop I'll check the two wires you described.

Thanks a lot for the detailed answer, I appreciate it!

EDIT:: Damn dad already towed it >.< I knew I shoud've checked here before I left for school (I leave at 6:45AM). I guess they're gonna diagnose the problem. I said "Let me do the work don't let them do any of the work."

He gives up too easily... This is why I'm studying for my ASE cert.!!

[Loudgp]

Could be a crank/cam sensor... I have seen them cause a no spark condition...

[TheDirtyBen]

crank sensor is my vote

[bluebomber]

When my crank sensor was bad it would cause the car not to start, but the cranking was not clean. It was firing injectors/spark at the wrong time and was leading so backfiring out of the intake! It was reading wrong though, when we unplugged it the car would start in closed loop.

[gatharmon]

Did you ever get the car running and what was the problem if so?

[TGP37]

My guess is crank sensor signal (7x sensor) wire melted on rear exhaust manifold cover

[pocket-rocket]

An educated guess on my part would have said CPS or ICM power was lost. I would lean more towards CPS, but since the last time this thread was posted to was 2004, I doubt the guy will be responding.

[TGP37]

oh wow, grave digging, lol.

[pocket-rocket]

Gotta give him credit, he did use the search function, something not a lot of new people do.

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