: Ignition Miss - '98 DeVille



Beau1399
05-17-08, 04:43 PM
My '98 DeVille has an ignition miss. It is getting worse over time. There's no real correlation with time, temperature, or RPM that I can identify, just a general miss. So, I am considering the following:

1) New plugs and wires; I'm not sure if they were changed at 100K miles, and she has 123K now. But I think this will be difficult (or expensive) with the FWD setup and I'm not at all sure it'd fix the problem.

2) Have a parts store test the Ignition Module; the module is a likely culprit but I don't really trust the part store employees. They might just fry the module, or mess up the test and sell me an unnecessary (and expensive) module.

3) Have a parts store test the Coil Packs (if possible) or just replace them; unfortunately, I don't think the coils are the problem, but I guess anything is possible. Does anyone know if they can be tested?

I am curious to know what everyone thinks of these plans. Right now I am leaning toward #2.

My fear is that this could be a Crank Position Sensor problem, and based on my previous (negative) experience with that sensor, I do not think I am equipped to fix it.

Thanks in advance for your help!

dkozloski
05-17-08, 05:02 PM
At some point you're going to have to trust somebody or just cherry pick random parts. Have you tried misting the wires in the dark to see if you have some bad ones? Have you pulled a plug to see how badly worn they are. At some pont you're going to have to substitute your lack of knowledge with money to somebody who knows what they're doing.

Ranger
05-17-08, 05:16 PM
CKP sensors are pretty reliable on the pre 2000's. I'd suspect plugs & wires at that mileage. Try misting them like Koz said. They are actually pretty easy to change.

Beau1399
05-17-08, 05:30 PM
At some point you're going to have to trust somebody or just cherry pick random parts. Have you tried misting the wires in the dark to see if you have some bad ones? Have you pulled a plug to see how badly worn they are. At some pont you're going to have to substitute your lack of knowledge with money to somebody who knows what they're doing.

I had never heard of misting wires. I will give it a try.

Beau1399
05-17-08, 05:33 PM
CKP sensors are pretty reliable on the pre 2000's. I'd suspect plugs & wires at that mileage. Try misting them like Koz said. They are actually pretty easy to change.

That's good to know... was there a problem after 2000?

I don't know if this affects all cars (or all mechanics), but I personally was not able to fix the Crank Position Sensor on my LeSabre. The miss would go away at first, but then return. My suspicion is that this happened because I was not using a special GM tool used to position the sensor.

Eventually a tree fell on the car and destroyed it, thus "resolving" the problem.

Submariner409
05-17-08, 06:20 PM
The coil packs and engine control module are the last things to worry about. If you can't document plugs and wires sometime at or just before 100,000 miles, that's your best bet for the money, and on your car it isn't too difficult. (Post-2000 to 2003 N* FWD units had a run of bad CKP's.) They're different from yours, and even your 2 CKP's are foolproof, installation-wise.

Go to www.rockauto.com (http://www.rockauto.com), www.gmotors.com (http://www.gmotors.com), or www.gmpartsdirect.com (http://www.gmpartsdirect.com) to look at plugs and wires......ACDelco 41-950 Double Platinum plugs for your car. $4.93 at RockAuto. Wires, again ACDelco, will run around $85 - $100.

Use a shop vac to really clean the plug hole area....after that many miles there will be a staggering amount of crap down in there. Make a vacuum adapter out of a piece of 5/8 or 3/4 hose. The same 5/8 hose will allow you to lift the plug out of the well. DO NOT lose the original spark plug wire-to-coil tower arrangement. It is critical. Your new wires may not be numbered as to cylinder/plug, so do that swap one at a time. One at a time. (If the existing wires have plug numbers, chances are they're OEM.) Plug torque is 13 - 15 ft/lb, dry.

No guts, no glory.............

Beau1399
05-17-08, 06:47 PM
Submariner, thanks for the good advice.


They're different from yours, and even your 2 CKP's are foolproof, installation-wise.

That's good!


Use a shop vac to really clean the plug hole area....after that many miles there will be a staggering amount of crap down in there.

I have never heard anyone else suggest that. I have definitely vacuumed around the plug holes before, and it seems like a really logical thing to do.

dkozloski
05-17-08, 07:00 PM
I had never heard of misting wires. I will give it a try.
Get the car running in a dark place with the hood up. Spray water around the spark plug wires with a spray bottle and look for arcovers.

Ranger
05-17-08, 08:03 PM
You are more likely to find some oil down in the plug wells. Seepage from the cam cover O ring seals around the plug wells.