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The ignition control module is only about a month old. Along with the coils. But I can take it off and take it to the auto parts store and they can test it. However I don't know if the problem will occur right away or what. To be continued

This thing is driving me nuts. It seems to happen now when I am slowing down for a turn or whatever, then getting back into the gas... not flooring it, not grandpa'ing it either, just moderate acceleration, then it goes into the dieseling thing... sometimes it fires back up, sometimes it takes a few minutes. I did notice this yesterday... the fuel pressure is back up to about 45-50 psi... it was down to 35psi on Saturday static or running. Maybe the fuel pump is crapping out. Does anyone know of a good handheld scan tool that isn't going to break the bank? Obviously, the GM Tech 2 is the one to have if you have $2000+ laying around... I did see a chinese knock off of the Tech 2 for $299!!! I have also been looking at the Autel brand of handhelds... seem to be quality, but I don't know which one I need. Obviously, I need one that monitors all systems.

The chinese Tech2's are just as good as the originals for our purposes. Check out my review: http://www.pontiacbonnevilleclub.com/fo ... 43833.html

so, I have an update to this but not a fix. Found a local guy with a snap-on scantool. He is a regular mechanic. We hooked it up and all looks good. Then... we were starting and stopping the car, while in park, and then it didn't want to start. We noticed that the crank position sensor had no signal from it. After constant cycling of the key, we got it to start. So, the signal from the CPS is intermittent. It also like to die when you kick it down into passing gear. The issue with the CPS is that it should kick out a hard code, per this mechanic, but it is not. So, that begs the question, why? He is suggesting to take it to a dealership because it may need a computer. your thoughts??

so, the problem isn't fuel pressure. I installed my helmetcam in the engine bay and watched the pressure gauge and the pressure didn't fall when the car acted up.. anywhere from 48psi at idle to 60psi at full throttle. I need some help fellas.

Are you sure it is not the ICM?
Did you try getting an OEM one from the junk yard or from Andrew at Bonnevilles Unlimited?
If you have fuel it has to be the Spark/Ignition.

Personally, I'd skip the dealership.

ICMs very frequently fail on our cars without setting a code; even the factory service manual states this.
IIRC, GM says the reason is that the failure occurs too quickly for the ECM to register it.

You can search the forum and find that this is the rule with Bonnevilles, rather than the exception.

As for the coils and ICM being only a month old, the very sad reality is that brand new parts are quite often defective right out of the box.
Since you've installed 2 ICMs without any change, it's safe to say it is not the ICM.

I'd replace the CPS, as you already know it isn't sending out a signal.
In fact, one of the telltale signs of a bad CPS is that, when cranking and not starting, the tach reads 0 rpms.

To avoid this, I buy either used parts from Harofreak00 (aka Andrew) or look for the actual OE part from ACDelco, Hitachi (for MAF sensors) or Delphi.
The ACDelco line now has 3 quality grades. The one you want is OE.
If unavailable, then Professional.
Avoid their Advantage line, as these are just cheaply made in China parts like the other cheap brands.
Delphi is good IF they are making the actual OE part--not just that they're an OE manufacturer---a distinct difference.

FWIW, this is how to test the CPS
http://troubleshootmyvehicle.com/gm/3.8 ... k-sensor-1

As with all electronics, it will only come up as bad while it's actually malfunctioning.

So, I took the ICM to Autozone for them to test... it tested good 10 different times. So, they swapped it out anyway for me. Took it home, put a generous amount of dielectric grease on the back of it, installed it and test drove. So far, no issues. I have driven it a total of about 1.5 hours since the swap. I want to believe it is fixed, but I also don't believe it... I know... paranoia...
I may be visiting Autozone again in the next few months ( if this one lasts as long as the first one) I was kinda forced into buying the ICM from Autozone because... get this..... I went there for some oil a few months ago.. got back in the car and nothing... had to switch our 3 coils and the ICM in the parking lot...my luck..

so, to date, there have been no random stalls....so, this must be the end of this issue.

Glad the issue has been fixed.
Thanks for reporting back.

Here we are again... the second "new" ICM was starting to fail too ( autozone brand)... so, I got Autozone to switch it out for a Delco ICM... So, maybe this time, it is the end of my issues.

I hope you have better luck with this one.
If it fails again try getting an OEM part.
I had no luck with brand new ICM'S. (all China garbage)
My problem was not solved until I got one from Andrew of Bonnevilles Unlimited.

I thought Delco was the OEM part!!

I should have said used OEM part from a junked car.
Sorry for the confusion.

dougtoth wrote:I should have said used OEM part from a junked car.
Sorry for the confusion.

I second that. You can get the entire bracket, ICM and coils from the JY here for less than $40. I think your best bet is to get them from Andrew of Bonnevilles Unlimited. - BC

sdxp787 wrote:I thought Delco was the OEM part!!

Yes, ACDELCO D1977A is the GM Original Equipment part.
You can look up parts on Rockauto.com, which tells you which ones they sell are OE parts. (Look in Pontiac Bonneville Club Vendor's forum for discount code, if ordering from RA)
What most of us have not been aware of is the root causes for repeated ICM failures.

Be aware that repeated ICM failures can be occur with perfectly good ICMs, when there is a problem with a spark plug wire, spark plug coil or poor grounding or, surprisingly, a bad alternator diode that sends too much AC into the electrical system.

If you have Bosch spark plugs installed or the spark plugs are old--replace them with good ACDelco spark plugs.
Search the forum and you will find numerous incidents where Bosch plugs were problematic.

This is a very interesting article detailing the reasons for repeated ignition module failures.
You should find it quite helpful to your situation.
The article is on page 2 columns 2 and 3:http://www.wellsve.com/sft503/counterp_v7_i2_20031.pdf

To measure the amount of AC voltage that is present in the electrical system, attach a digital voltmeter to the battery and select the AC voltage scale.
While the engine is running you should not see more than .5 AC volts on your meter.
Results in the article were that they found .9 AC volts at the battery.
He replaced the alternator and the ICM worked ever since.

I can not say whether or not your Autozone ICMs were defective. Modern day Chinese made parts have higher than should be expected failure rates.

Personally, I'd do the very simple AC voltage check and get rid of any Bosch plugs at the very least.

I will do that.. thank you

So, this gremlin is back... I have had a Delco ICM in it for a little over a month.. worked fine up until last week. The plugs in the car are AC Delco Iridium, I don't know the brand of wires... So, the other night, I changed the plugs to standard Autolite 606, changed the wires to Denso. ( only because I didn't know what plugs were in it at the time and I already had the parts) It seems I can make the car die by applying enough throttle to downshift to a passing gear, not every time, but I have atleast narrowed the dying issue to this cause. The car will start back up on the second or third try. I am ready to set this thing on fire.

This is a very interesting article detailing the reasons for repeated ignition module failures.
I do suspect there's something going on besides the ICM.

The article is on page 2 columns 2 and 3: http://www.wellsve.com/sft503/counterp_v7_i2_20031.pdf

Excessive AC from the alternator is something I never would have suspected as a cause of repeated ICM failures.

Attach a digital voltmeter to the battery and select the AC voltage scale.
While the engine is running you should not see more than .5 AC volts on your meter.
Results in the article were that they found .9 AC volts at the battery.
They replaced the alternator and the replacement ICM worked ever since.

I don't believe the new ACDelco ICMs are made in China. I think they make them in Mexico.
You can always try dougtoth's solution of a used OE ICM from Andrew aka Harofreak00.

Well, I think my problem is solved but I am not sure why. The last thing I did was to unplug the ECM... looked at it...pins seemed clean, I greased it up with dielectric grease, and haven't had a problem in 3 weeks.... I hope I just didn't jinx myself. .