PontiacBonnevilleClub.com

Hi Guys,

Could really use some help.

This is my wife's daily driver.

Has been running great for the past 24 months and then last week, had a flash SES light and then it went out.

Tried to start it the next morning and ran really rough.

Here's the condition of the car.

New plugs and wires within the last 24 months.
New ignition coils with the last 24 months.
New Tees and vacuum hoses in the last 36 months.
New fuel pump in the past 6 months
No Coolant leaks

Need to figure this out fast.

Any suggestions would be greatly appreciated.

Thanks so much!

Given that it's a P0300, I would give the ignition control module a try as well. It sits under the coils.

Is there a way to test to see if the ignition control module is bad? Its expensive to replace parts, especially this one.

Thanks!

hi, please go through this site...............http://easyautodiagnostics.com/gm/3.8L/ ... articles-1

page 3 has coils and the module -I would start there

Unfortunately, aftermarket ignition parts today are nowhere near the OE quality, so it may be a bad new part.

I'm usually not one to buy used parts but I trust the OE used parts much more than new replacements---as do so many of us here--for good reason.
If it is the ICM, then either buy a good used one from forum administrator Harofreak00 (my #1 choice),a junkyard or ebay .

Some brands of replacement parts are known to create issues in our cars (Bosch spark plugs and O2 sensors, for example).

It could be fuel related due to a bad sensor or fuel system part.
Also worth looking at is fuel pressure.
A faulty fuel pressure regulator can be the culprit--and don't discount a clogged fuel filter unless it was recently changed.
FWIW , I've read of people using less than 91 octane fuel and suddenly getting both these codes.

This should also help you to figure it out
http://troubleshootmyvehicle.com/gm/3.8 ... re-codes-1
Here's some more good info on P0171 & P0300
https://www.engine-codes.com/p0171.html
https://www.engine-codes.com/p0300.html

P0300 is a multiple misfire code... Do you have any way to scan by cylinder (DHP Powertuner is how I scan mine). See if its on a specific cylinder or pair of cylinders..
The Usual Culprits
-ICM (just did mine)
-Coil
-Plug, wire
-injector
-Fuel Delivery (Filter, pump, ect..)
-Maybe O2 sensor (doubt it without the code for the sensor)

P0171 is a Lean code. I would try spraying carb cleaner on all vac lines and around intake gaskets and Injector O-rings with the engine running and see if the engine revs up, if so you found your leak. Or if you have access to a "Smoke Machine", I smoked my engine and found a big leak really fast on the vac block on the blower.

Hope this helps.. Best if you can scan/smoke the car rather then throwing parts at it.
S

First, thanks for all of your help.

I purchased an HEI spark tester and I got a spark on #1 cylinder and not on #3.

Since the plugs and wires were new ( I used Belden Premium 7mm) I figured the culprit might be the Ignition coil.

I had purchased a set of used coils from Harofreak a year or so ago (they were the blue ones) so I was pretty sure they weren't a problem.

I still had the original ignition coils so I changed them out just to see if it made a difference.

No difference.

So, in order to eliminate the Ignition coils, I purchased a new one from Napa. It had a 5 year warranty, so I figure if it doesn't work I'd return it and get another.

Tested the coil in the 3/6 slot on the ignition control module.

Pull the plug wire on the #3 cylinder and put it into the HEI spark plug tester.

Still no spark.

Makes me pretty sure its the ICM.

The #1 cylinder sparked nicely as did the #5.

Am I correct in thinking the ICM is the problem?

Don't want to spend a lot of money changing parts.

Need to get this puppy back on the road.

Thanks again for all your help.

- Bret

HI, i WOULD PULL A WORKING ONE FROM A DIFFERENT SLOT AND TRY IT IN THE assumed dead slot - if it works in another slot, the icm is funky - clean contacts and see if it improves.

Thanks again.

Just pulled all of the ignition coils off and cleaned the baseplate for the ICM and the bottom of the ICM.

Also cleaned all of the contacts that the coils connect to on the top of the ICM.

The problem persists.

The #3 cylinder does not spark.

It looks like the ICM may be bad.

What does anyone else think?

What else can I check to be sure the ICM is bad before I buy one?

It seems odd to me that only one coil would be affected by a bad ICM but it is electricity so anything is possible!

Any additional ideas or things to check?

I meant the coil to icm contacts - on the bottom not the metal posts on top.....can you swap the icm with a wreckers or used one to diagnose?

mundster wrote:Thanks again.

Just pulled all of the ignition coils off and cleaned the baseplate for the ICM and the bottom of the ICM.

Also cleaned all of the contacts that the coils connect to on the top of the ICM.

The problem persists.

The #3 cylinder does not spark.

It looks like the ICM may be bad.

What does anyone else think?

What else can I check to be sure the ICM is bad before I buy one?

It seems odd to me that only one coil would be affected by a bad ICM but it is electricity so anything is possible!

Any additional ideas or things to check?

If you read the first link I provided earlier, you would have gotten to here:
http://easyautodiagnostics.com/gm/3.8L/ ... ck-tests-4
Which is the further testing you are asking for.

ok, so your saying that #3 coil wont spark but the other post on the same coil - # 6 does spark???d

if you get spark from one post, the ICM is good for power so check for signal

do it here..........http://easyautodiagnostics.com/gm/3.8L/ ... ck-tests-4

so yours would be case 3 on the page.....

sounds like a bad ICM to me. they are very common component to fail. I got a bad one out of the box from Advance auto... had been opened and returned.... so how knows what the previous person did, I think they returned a bad part off their car. 2nd replacement fixed the problem.

S

When I had a flashing P0300, it was the ICM. The coil pack for 2 and 4 was not being activated by the ICM.

Most certainly sounds like a bad ICM. Get one from harofreak00. If you let him know what's going on, he can help troubleshoot as well, and he often will return parts with no fee, you just pay return shipping. ICM costs $5 to ship back. Worth it.

Just realized that I hadn't updated this post.

I replaced the ICM and it solved the problem!

Thanks for all your help!

This forum and community is awesome.

It makes owning a Bonnie very rewarding