2003 Pontiac Montana No Spark

[grandamle91]

The one behind the crank is working. It shows 180-200 rpms when cranking. I tried another crank in the block that shows the same as the other one did

[1988GTU]

If both sensors are in fact good producing proper digital wave signal typically of an on/off 9.5-10 to 0 volts DC then I'd pull the block ckps and borescope the reluctor ring for debris or if the ring is no longer press fit as required to spec to allow for engine reliability.

[grandamle91]

3.8 swap sounds easier

[bszopi]

Have you checked the wiring to both sensors? Good chance you are just getting a fault do to an intermittent grounding of the signal.

[grandamle91]

All the test I did were right at the ign mod, were are the ground points

[1988GTU]

Go all out with an lt1 swap. If you're gunna go anchor, at least pick something with more pistons.

[Guest]

Even if the 24x sensor was missing from the car, it will not effect the ability for the ICM to produce spark, with the 7x sensor installed, connected and working.

Check the 12v feed to the ICM when you have the problem. If there is no 12V trace the wiring and see if you can find a break.

[grandamle91]

Got 12 volts fuel primes, so the ign is powering up. All fuses are good. The Las time I got it running was messing with the big connector on the ign mod

[Guest]

Fuel pump priming is not an indication that the ignition module is getting 12V.

Check for connection between the ICM and the ECM.

[grandamle91]

Fuel pump runs through the icm, 12 volts are going to the icm

[Guest]

Fuel pump runs through the icm, 12 volts are going to the icm

Fuel pump does NOT run through the ICM.

The 12V feed to the ICM is separate from the feed to the fuel pump. Even if they shared the same fuse, that does not negate a break in the wire to the ICM, or even at the connector itself.

So you need to test for 12V at the ICM with a multimeter, no other (easy) way to verify that 12V is indeed getting to the ICM. An RPM reading using a scanner plugged into the ALDL would be a good indication that the ICM is indeed powered up, but IIRC the 24x sensor can also indicate a crank RPM using a scanner, so you have to be sure you're looking at the correct parameters.

That being said, just because the ICM may be getting 12V and the PCM may be seeing an RPM signal, does not mean that the coil drivers inside the ICM are good, though to have all 3 intermittent and fail to work and not work at the same time would be unusual.

[grandamle91]

Why does it when I plug the plug back in with key on the pump primes?

The icm has been replaced with a known working one, even the crank sensor.

Last time I got it running I was messing with 6 pin connector

[Guest]

Because what is happening is that there is a DRP (Distributor Reference Pulse) then sent to the PCM (as you connect the long connector on the ICM), that then turns on the fuel pump for a brief second, until the PCM sees a lack of DRPs.

Since you have an RPM indication from the ALDL that would be a good indication that there is 12V at that particular moment. When there is no spark, do you still get an RPM reading from the PCM?

Are you sure you're losing spark and not fuel? The ICM and coils will produce a spark without an ECM/PCM even in the vehicle, it just needs 12V, ground and the signal from the crank sensor. I have never seen all 3 coil driver outputs be intermittently bad at the same time.

[grandamle91]

I got fuel, can smell it and the plugs are wet. No spark on any coil. 12 volts at the coil but doesn't get the ground reference when cranking.

[Guest]

The only two possibilities then are the coils themselves or the ICM. During crank, spark is produced by the ICM itself, once 400 RPM or so (most bins I've seen have 400 RPM as the threshold), then the PCM will take over.

It's possible that if one coil is bad or on it's way out, it could cause the ICM to go into a sort of self protection mode (shutting off all 3 coils), but I haven't tested for this specifically with any of my modules.