Wash the car, lose a cylinder!

[Riktar]

Took the wifes car through the local car wash (Assembly line- brushes) to get the salt off the car and opted for the underbody flush. The car entered running just dandy and left with one (maybe 2) cylinder not firing. I was about 25 miles from home and figured that something just got wet and that the problem would straighten itself out. No dice.

 

Is it possible the underbody flush was strong enough to get up into the engine and cause a short in the seconday part of the ignition? And if so I would have guess that once dried out the problem would disappear. I just went out to try the car this morning and it still is missing.

 

We just changed the crank sensor about 2 weeks ago since the engine just died and no spark was coming to any of the plugs. I am guessing that the crank sensor wouldn't have failed (faulty new part) since the car would simply stop running.

 

Anyone ever run into this? While it could be coincidental I am more inclined to think something got wet and is now fubared.

 

For starters I am going to try pulling off the plug wires one at a time to isolate which cylinder isn't firing. I really hope this comes down to one of the front plugs. I have never tried changing plugs on this type of car and since the temp is in the single digits (With wind to boot) I want this diagnosis to go as quickly as possible.

 

Anyone got some tips for easy rear plug changing?

 

The car:

1991 Pontiac GP 3.1L auto 2dr

 

Thanks for any advice/tips

[musthavemuzk]

do not really have an answer for your first question, but for the last one i do.

 

in order to change the rear plugs on the 3.1 you need to loosen the dog bones and rock the motor forward.

might need a hand in this all depends on how coordinated you are.

on the front top of the motor are two dogbone motor mounts. remove the front bolts from these. do not lose them. if you noticed there is a ring on the bottom side of the driver side one. when you rock the motor forward you will be putting one of the bolts you just removed through the mount and this ring to keep the motor rocked forward while you work on it.

hope this helps.

 

Monty

[Guest Anonymous]

I'm betting there is still water in one of the plug wire ends.

[Riktar]

Thanks for the replies guys:

 

musthavemuzk: Thanks for the tip. I figured the Dogbones had to be deattached to get the motor forward but I DIDN'T KNOW about the bolt in the ring to hold the motor forward.

 

redturbo90: I suppose the water thing is possible. I sprayed the pee-waddles out of the coil packs with WD-40 this morning to see if that would help. I did not however, remove the plug wire caps. Considering the angle they are at I will remove all of them (One at a time of course) and see if any water may still be in there.

 

Other update: I removed one of the wires from the spark plug itself and started the car to see if that was the cylinder that was mis-firing. It wasn't and so I moved onto the next one. Funny thing about that: When I started the engine on the second wire I didn't hear the clicking sound that was made by the first wire when I started this test. So I went to look at the wire and what I saw was the spark coming out, stopping for a short period of time, then start agin, then stop, etc. Curious I put that plug wire back on and removed the first one again. Constant arcing while the car was running. Too verify I pulled the second one again placing the boot end in the same place as the first one. Same result.

 

Weak coil pack? I don't know but after I pull all the wires off the coil pack ends to verify no water in the boots I am going to pull the spare coil pack I have from my old 89 buick regal and swap them out to see if the problem follows. If it doesn't problem solved. If it does at least I detemined that the packs are ok. And since that is the easiest thing to replace on the ignition I will eliminate that.

 

Thanks again guys.

[Riktar]

Well swapping the coil pack assembly seems to have done the trick. I will take Poncho for a ride to confirm this but the idle and load tests show no sign of mis-firing.

 

One final note (For now) on the coil packs: 2 weeks ago while I was out of town the crank sensor failed on my wife and was replaced by my brother in-law. Along the trail of diagnosing he did the first swap of the coil pack from the Buick. How do I now know this? Well when I went under the hood of the Buick to take it's coil pack I was greeted by an empty space. So after questioning my wife and her brother I found where they had placed the original coil pack from Poncho. And so the swap began.

 

Imagine my surprise when removing only the 2 side bolts resulted in the coil pack falling out. I asked my bro-inlaw if he didn't tighten the bottom bolt completely since it was missing. He tells me that he didn't put the bottom bolt back in since it was too hard to get to for re-assembly. Go figure. You can take it out but you can't put it in?

 

Since I have no clue where the missing bolt is now I am wondering if the missing bolt could have generated enough vibration to cause a problem with the swapped coil pack? Also, the coil pack out of the Buick was from a 2.8 motor. I am assuming that there is no great difference between these 2 parts. But I am wondering if I am going to have another failure in 2-3 weeks leaving the pack "boltless" on the bottom. It feels tight, as in I can't move ar wiggle it. I have to believe that the bottom bolt is needed since GM wouldn't invest even the lousy 1 cent for that lower bolt if they didn't have to.

 

So I am left with more questions: Was the car wash a coincidence? Is my brother-inlaw an idiot? Am I just being paranoid?

 

And what about Mary Lou?

[Guest Anonymous]

Don't bother putting the lower bolt back in. Every w-body I change coil packs or the ign. module on is missing that bolt. Why? Cause I took it out, aimed for Detroit and threw that mofo as hard as I could, hoping to hit the engineer that wanted it there. I've never had a problem with it not being there. Except when I got my TGP and that's cause the previous owner left all 3 bolts out. The coils were laying against the oil line going to the turbo.

 

The 2.8 and 3.1 uses the exact same coil.

 

I think the car wash was a coincidence.

 

Who is Mary Lou?

[phantomFE3]

damn dude all you would have to do was just drive it for like half an hour to 45 minutes and it woulda dried everything out, looks like you took the scenic route on this problem

[Riktar]

Well Poncho drives like new again. I won't sweat the lower bolt. Thanks for the confirmation on not bothering to replace it. Must have been just a wierd coincidence. I'm just glad the problem is solved. Now I just have to wait for my hands to thaw. You wouldn't believe how jhward it is to type with numb fingers.

 

As for Mary Lou: I first heard that question raised on one of my Cheech and Chong (Boy did I just date myself or what) albums. Can't remember if it was the Big Bambu or other albums. It was the ending to one of their skits, done in Soap Opera fashion.

 

phantomFE3: I don't think so. I checked the odometer and since I put almost 100 miles on it since yesterday afternoon at 2:00 I don't think it ever would have dried out. And since I sprayed a D-Cup amount of WD-40 on the coil pack it probably wasn't water.

[phantomFE3]

well thats interesting, because when i powerwashed the engine bay of my car and had the exact same symptoms as you described, i let it idle for 20 minutes, and then went and drove around town with the gf for about an hour and after that it ran fine. all it needed to do was dry out the moisture that was in the coil packs or the plug wires or wherever it was at.

 

but reguardless, im glad you got the car running good again, it always sucks when your car doesnt run quite right and you dont know exactly whats wrong with it.

[Riktar]

but reguardless, im glad you got the car running good again, it always sucks when your car doesnt run quite right and you dont know exactly whats wrong with it.

 

Ain't that the truth!

[89oldscutlass]

I had one of my coil packs go bad after washing my engine. I thought it would dry out and work again but it didnt. The cold water on a hot set of coil packs is hard on them it usually causes them to miss till they dry out but when they are old it usually takes them out after a couple of engine washings.

[913_4se]

a bad set of wires or worn plugs will take a coil pack out before it should

 

just what i was told !!!?

[W-Body Geek]

I've wonder about the underbody spray pressure when I went threw the Carwash..Somewhere in the back of my owner's manual it says that if you live in a state where it snows, you should take your car every now and than to a dealership to get the road crap spray'd off...Anything is possible,rite?.... :?: