NEW CPS (by Shop) now runs rough/dies after hot

[spoiledred94]

I was getting rough idle to full on missing to dying and no restart intermittent and occurring more often. When I got the P0330 or P0336 (cant remember) I had the CPS replaced. Now runs fine after a tough start and runs fine for an hour or so until its fully hot then dies/no restart for an hour or so. They tried a new ignition module. Same thing so I swapped in some used coils and no change. They tried resetting the CPS code or whatnot with a scanner-same thing.

The mechanic showed me that if you pull a coil plug wire boot the sparks flew every where. There were orange sparks and non existent sparks on some and 1 had a bright blue spark. That was why I swapped in used coils/ Id like to check the sparks at the coils again/

I/m lost and am about to lose my job if I cant fix this. Please if you know something let me know.

Kris

[spoiledred94]

I got a P0336 cps code again
Then I got P0302, cyl two misfire
tried for spark at the coil with wire off. NO spark.

What can cause a cyl two misfire when hot?

[Jfridge92]

Since you're not getting spark on that coil, even though they swapped it, you need to look again at the cps, all the wiring between the cps and icm, and try a set of known good coils/icm. Even new parts can be bad out of the box.

[spoiledred94]

Possible bad wiring was about my least hopeful next step. It is going to be a lot of double checking and following wiring diagrams off the net if I cant come up with something more close at hand.

Coils are out as the problem then? My two coils were used and old. I get the feeling I should do a resistance test on the them.

Ill figure it out. I appreciate your help fridge

[harofreak00]

If you move the coils around and the problem follows the coil, its a bad coil.
If you move the coils around and the problem stays in the same spot, its a bad ICM (the module under the coils).

A bad CPS, will not cause one coil to fail. I'm betting its the ICM.

[spoiledred94]

1st I dont know what all the different coils are doing. I do know cylinder 2 was giving a misfire code and showing NO spark at cyl 2 coil.

I see what you're saying...if coil A has no spark and you swap in a new coil and it is bad too then its the ICMM.

Ill do that that tomorrow

[spoiledred94]

Today has been a bear and I am pretty thin minded here. The bad spark on the # 2 coil moved to the next spot when I moved that coil. Bad Coil. Replaced coil with another used one. No start. Down for the day.

Thank you a lot for the help

Kris

[harofreak00]

No start for what reason? Doesn't crank? Doesn't fire?

[spoiledred94]

No start for what reason? Doesn't crank? Doesn't fire?

No start due to bad ignition system, spark at coil ranging from yellow to none to Bright blue.

Car cranks over great but note I have been hammering this starter a lot lately

It is on its third ICM. 1 the original, 2 my 94 SE ICM and now a parts pro ICM from Oreilly to Rick's shop into my 01. Same as always.

On your suggestion its still the ICM I think I should go out to the JY or the used parts shop and get 3 coils and an ICM $25. An off the shelf replacement at $142 is out for now.

EDIT:
she got me to work and almost back from work last night. I had to wait for a train and she died as I was turning home.note fuel pressure is 50psi. After having gone through this cycle of starts cold runs and drives for 20 Min or so, then dies and then wont start until temp goes down to 130-140 F

[MKMike]

I came across an 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

While the entire article was interesting, I would not have suspected that a failing alternator could wreak this particular havoc.

[RJolly87]

I came across an 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

The "Fine Tuning" question in the January 2003
Counter Point concerned a 1992 Olds Delta 88
that has experienced multiple ignition module
failures. Along with the ignition modules, the
ignition coil, ignition wires, and spark plugs have
also been replaced. All system grounds have also
been checked for excessive voltage drops. What
could cause these ignition modules to fail?
There are three causes for repeat ignition control
module failures. The first and most common cause
is high resistance in the secondary ignition. On
this vehicle, this would include the ignition coil(s),
ignition wires, spark plugs and cylinder
compression. All of the ignition components
mentioned have either been recently replaced or
tested, so we should be able to rule them out.
There was no mention of a compression increase,
so for now I will assume all is well there.
The next most common cause for repeat module
failure would be a bad system ground. Voltage
drop tests have been performed on the system and
no problems were found, so I am also going to
assume everything is okay in this area
The last possible cause has to do with the charging
system. As the rotor in the alternator turns, it
generates an AC current in its windings. It is the
job of the rectifier bridge to convert this
AC voltage to DC voltage. If the rectifier
is beginning to fail, it will allow an
unhealthy amount of AC voltage to enter
the vehicle’s electrical system. Given
enough time, this AC voltage will cause an
ignition control module failure. It may also
damage other vehicle electronics.
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: Tom checked and found .9 AC volts at the
battery. He replaced the alternator. The ignition
control module has been working fine ever since.
Although we did receive a large number of replies
to last issue’s "Fine Tuning" question, we did not
receive any correct answers. Most of the answers
we received pointed to an intermittent crank
sensor as the cause of the problem, which I find
interesting. Within the next few issues, we will
take a look at different crank sensor designs,
including how they function, what happens when
they become intermittent and how to test them.

That's very interesting, something I don't recall ever being mentioned on the forums. Is this something that is assessed with a charging system test?

[MKMike]

I would imagine that it would depend upon the particular analyzer being used and the skills of the technician.
The guy at your local chain store or garage might not have been trained to recognize AC trouble in charging systems.
As you can see, if you have a voltmeter you can test for it very easily.
Here's another interesting article on the subject: http://www.pvv.org/~syljua/merc/TooSeptST07.pdf

[ThisGuy]

@spoiledred94

I think I know what your issue is...there was another member(beamer) having essentially the same problem. What is happening is that you have a bad coil back feeding to your ICM and frying it prematurely and causing a rough idle and dieing problem...The CPS was probably coincidental.

Beamers thread: http://www.pontiacbonnevilleclub.com/fo ... 45581.html

This link will explain your issue: https://www.youtube.com/watch?v=S8Z4iv7-Ke8

[spoiledred94]

Thank You This Guy, its nice of you to help.

And I still need help.
I replaced the module for the 4th time. 1 at the shop, 1 at the shop with my old 1994 one and one from a JY and then I replaced it again: 3 new coils and another new ICM all replaced at the same time (with thermal grease and dielectric grease. I hope that is not the problem. Otherwise the install went fine. I;m still getting NO spark at all on towers 2 and 5 as before. While all the others are now bright and white.

Does any one have a lead on a wiring diagram for the ICM?
I also did a test yesterday on the voltage on three leads of the ICM wiring before installing the last new one.

power supply-good 12v
Ground check-good 12v
Power circuit-12v

I am avoiding checking CPS 3x and 18x circuits because the amount of work to do it with DVM. But was told if I am getting any spark at all the CPS works anyway.


I know there is a lot to look at. I hope if you know something specific you will post it for me.

[MKMike]

If you read the article that I had linked earlier, you should be able to get things sorted out....

I came across an 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

While the entire article was interesting, I would not have suspected that a failing alternator could wreak this particular havoc.

[spoiledred94]

I didn't much from that...

[MKMike]

I didn't much from that...

I don't understand why not...
It states all the possible causes of repeated ICM failures, in order of most to least common, as follows:

There are three causes for repeat ignition control
module failures.
1)The first and most common cause
is high resistance in the secondary ignition. On
this vehicle, this would include the ignition coil(s),
ignition wires, spark plugs and cylinder
compression.
2)The next most common cause for repeat module
failure would be a bad system ground.
and
3)The last possible cause has to do with the charging
system.
If the rectifier
is beginning to fail, it will allow an
unhealthy amount of AC voltage to enter
the vehicle’s electrical system. Given
enough time, this AC voltage will cause an
ignition control module failure. It may also
damage other vehicle electronics.
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.

The last cause--your alternator sending out excessive AC voltage (instead of just DC voltage) is not an insignificant possibility.
Excessive AC will eventually fry many more expensive electronics besides the ignition circuit.

Rather than guessing, you can follow the steps to check everything.

This site has some excellent step by step info on diagnosing troubles with 3.8L engines
One article that may be helpful to you is this:
http://easyautodiagnostics.com/gm/3.8L/ ... ck-tests-1
There are other diagnostics on that site, so you might want to bookmark it for future reference.

In any case, I hope you get it sorted out and let us know what the fix was.

[spoiledred94]

MMike. Ill test the AC content like you said. I am also going to add a dedicated ground. Im going to pit new beldens and plugs on today to reverse all the fouling that must be going on. the easyautodiagnostics is the site I have been working from. i have tabs of theirs across the top and Ill keep reading. Thanks

[MKMike]

I think electrical problems can be the most maddening of all.

It would be an easy enough fix if it's the alternator--and cheaper than more ICMs and coil packs..
Sometimes brand new ACDelco alternators are even cheaper than rebuilds.

That website even recommends checking compression, since it is in their list of the 1st tier of most common causes.

Hope you get it figured out asap.

[spoiledred94]

Thank You MMIKE. I will get it figured out soon. My family is offered up a little bit for a shop to diagnose it. Back to the old shop to let them finish from where they had to be cutoff or new electrical specific auto shop?

I exchanged my 3 year old belden 7mm premiums for new ones and got 6 autolites. Not the original problem but I think theyll clear things up/