View Full Version : Engine likes to shut off in rain/wet snow/high humidity

03-02-07, 05:32 PM
My engine runs great, but whenever it's wet outside my engine dies at a stoplight. It only does this when the car is wet, parked on top of a driveway lake, getting out of a car wash, heavy snow or just a humid day. Engine starts right up after it dies and if the engine is warmed up long enough the problem goes away, so it's always the first half an hour after starting the car.

When I replaced the plugs & wires I didn't apply the dielectric grease on the spark plug's connector, is that why? Like moisture gets into the wire plug and high voltage arced to the engine block causing a short, and effectively shutting down the engine?

03-02-07, 07:27 PM
If you used OEM AC Delco ignition wires they are impregnated with the dielectric grease and there is a statement in the service manual that states NOT to use it as it can cause carbon tracking and misfires.

Did you use OEM plugs and OEM wires?

Check your ignition wire routing make sure they are not next to metal or side by side. The problem you are having, I would immediately think its ignition wires. Try parking the car in pitch dark and observing the ignition wires with the vanity cover off. Spritz the wires with water and see if you induce any arching near the wires or the coils. Make sure the wires are firmly snapped in on both ends..

Report back what you find out


03-02-07, 08:40 PM
I replaced it with AC Delco plugs and :thepan: NAPA wires, so no it's not AC Delco wires even thoguh they have a lifetime warranty. The box came with some dielectric grease but uh, I didn't use it cause at that time I didn't know what that was for. I didn't even measure the gap in the plugs(again didn't know that before), but was told they're factory gapped to the correct distance(really?). It's way too cold and wet and snowy right now and I can't really do anything until spring time, which in WI is around June lol.

03-02-07, 08:59 PM
Plugs are usually gapped right, but you never know for sure unless you check them. I can't imaging plugs or wires causing the engine to die. Maybe a rough idle. I would check the 4 connections on the ICM or maybe the CKP sensors.

03-02-07, 09:43 PM
The grease is typically used to permit the boots to be pulled off the plugs with ease, yes it helps to create a moisture barrier, but I dont think not using it created any problems for you...

I agree with Ranger, if the plugs were poorly gapped it probably would create roughness.. However, we had a big disagreement on the other board trying to decide if the gap was .050 or .060... The question is, what does the tag on your hood say, and what were the plugs gapped at.... The guru once said that whether they were gapped at .050 or .060 would not matter..and that statement always surprised me.. I would check the gap at some point if I were you.. but I dont think that is your stalling problem..

I think that Ranger had a couple of good suggestions, also check your fuel filter and clean your Idle Air Control Valve and your Throttle Body.. But the odd thing about your problem is that its an issue when the engine is damp....

03-02-07, 11:38 PM
The morning moisture in the spring and fall gets me too, but in the summer is totally fine...I took this car from WI to St. Louis and back without a problem so I really don't think it's a huge problem. The moisture has something to do with something....

03-03-07, 09:23 AM
This is a weird one. I wonder if the PCM will save a snapshot of what occured right before the stall. I don't suppose a code is set for Stall?

I found this list of information regarding stalling:
Check for proper ignition voltage output with spark tester J 26792. Refer to Secondary Ignition Diagnosis.

Remove spark plugs and check for the following:
Wet plugs
Improper gap
Burned electrodes
Heavy deposits

An improper spark plug gap will cause a driveability problem. The spark plug gapping should be done using a wire gauge gap tool (J 41319). If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

Visually/Physically inspect Secondary ignition for the following:
Ignition wires for cross firing.
Ignition wires arcing to ground.
Ignition wires for proper routing.
Ignition coils for cracks or carbon tracking.

Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as water is applied.

Check for loose ignition control module ground

Check PCM grounds for being clean, tight and in their proper locations

Most intermittent problems are caused by faulty electrical connections or wiring. Perform a careful visual/physical check for the following conditions:

Poor mating of the connector halves or a terminal not fully seated in the connector (backed out).

Improperly formed or damaged terminal.

All connector terminals in the problem circuit should be carefully checked for proper contact tension.

Poor terminal to wire connection. This requires removing the terminal from the connector body to check.

Ignition coil shorted to ground and arcing at ignition wires or plugs (spray the area and listen and look for high voltage discharge)