2002 Bonneville - cranks but no spark

[T-man75]

Hello,
I have a problem I have been fighting for some time. The car will run fine, then die. It may or may not start up again right away. It may not start for several weeks. I did do an engine swap. I bought the car with no engine, so I do not now if it had this problem before.

Here is what I have checked or done so far:
-Fuel pump and pressure - OK
-Checked ICM and Crank Position Ssensor. I didn't get the voltage values that the test looked for, but the test didn't indicate a bad CPS. A knowledgeable person said it was the CPS "trust me". I went ahead and changed it since I no other ideas. The car started up and ran for awhile, then back to the no spark situation. I got it restarted a couple times, now it will not start at all after 2 weeks. No spark.
-Swapped out the ICM and coils with another car (Grand Prix). The Bonneville ICM/coils fired right up in the Grand Prix. The GP ICM/coils didn't make a difference in the Bonny.
-I swapped out the MAF just for the heck of it. No start, no spark.

I am going to look at the grounds and fuses again since it has been awhile since I looked at them to make sure I didn't miss anything.

What else could be causing no spark? After looking through other posts, I came up with a few things. I need someone to share their experience and give me some advice... any advice!!

Here are my new ideas:
- that little module looking thing that is grounded to the engine block, right by the ICM/coil. What is this thing for?
- ECM - how can I test this?
- Security system? Chip in the key? How do you check this? Would it cause a no spark or a complete shut down (no crank, no spark, no start)?
- What other sensor could cause a no spark? I read the cam sensor can fail, but will not cause a no spark not start condition.

Thanks ahead of time!! If I can't figure this out, there will be an 02 Bonny for sale!!!

[MKMike]

A security system failure would disable the starter. Since yours cranks, it isn't the security system.
The ECM ground is in a ground pack by the coil on the block--which also contains the grounds for the trans. internal mode switch, eng oil level sw. and the MAF.
According to this site--which is a good one--a bad cam sensor could cause a no start, no spark condition: http://troubleshootmyvehicle.com/gm/3.8 ... ondition-1
Following the steps on that site should pinpoint the issue.
Keep in mind that, although you replaced the CPS, the now commonly made in China parts often are defective right out of the box/fail soon after installation.
Using the site above's troubleshooting will give you the answer.
Let us know how things turn out.

[AJT2004]

If the tach moves when you crank the engine, the crank position sensor is likely OK. Recheck your connections and wiring at the ICM.

[T-man75]

Thanks for your replies.

Ok, I did a little parts changing. Of course, realizing the parts came off a pulled engine so I don't know if they work or not.
I still have the swapped MAF sensor installed. I still had the crank/no spark condition.

I went ahead and swapped the cam sensor. Still no spark/ no start.

I unhooked the harness from the MAF sensor. The car started up and ran. I plugged it back in and it stalled within a few minutes and would not start again. I unplugged it and it started after a few attempts. I let it run for a 1/2 hr, which is the longest it has run since it developed the problem. I plugged the harness back in and it continued to run. I even shut it off the work on another issue with the ABS light being on, and it started after that when I had to pull it out of the garage.

This makes no sense to me. Would a faulty MAF create a no spark condition? I have not found this in all my research. I am going to start it again tomorrow after work and let it run as long as I can to see if it stalls again.

Let me know what you think.

Thanks.

[scooberu]

I had an intermittent start problem in my 89 Bonneville. I didn't go so far as to switch sensors on it, but I did put in seafoam with some positive results. The seafoam was a complete red herring; what I needed was new spark plug wires. If you can get your car running somewhere it's dark, take a spray bottle and spray water on the spark plug wires. If they look like a twinkling string of Christmas lights, that's the problem.

[AJT2004]

How and where are you checking for spark?