PCA Forums

So I've got this really weird issue with my car. Bought it about a year ago now, being told that it had a 'new' rebuilt engine in it. Also had the paperwork to prove it. 'New' engine only had 5000 miles on it, and aside from the AC not working, it didn't have any other major problems. For $1800, great deal, right?

Well, it would be. But it seems when they replaced the engine, they replaced essentially just the block and internal components. Everything on the outside is either old or crappy parts. Since I've had it, I've replaced the AC Compressor and most of the AC components, spark plug wires, spark plugs, EGR valve, PCV valve, and misc other components.

I have no problem with this. I knew what I was getting into. It's a used car, old car, and I'm willing to do the work. But there's one problem I can't figure out. I talk to my uncle who seems to know a bit about cars, and he says it's 'normal'. I call BS.

Whenever it rains, my car becomes really sluggish. The best explanation I can give is that it's like losing two cylinders. Acceleration is crappy, top speed is about 50MPH. I try my best not to drive it when it's like this, but when you get caught driving in a freak rain storm, there's not much you can do.

It's not just rain either, really. The car used to sputter while idling even when dry. I took it to the shop, and they said the spark plug wires were arcing. I had them replaced, and that seemed to fix the sputtering-while-idling issue. It also seemed to fix the rain issue too, until tonight, when I was driving through a huge rain storm, the problem returned.

I'm beginning to suspect it's the coil packs. This particular model uses a 2.2 4-cylinder with electronic, computer-controlled ignition. Instead of a distributor, it uses two coil packs to send electricity to the spark plug. My guess is one of these coil packs is not sealed properly/cracked/something, and water gets into it and stops it from functioning properly. The shop I went to said to change the spark plug wires first, then try coil packs if the problem comes back.

My question is, what else could cause this? I don't want to spend another $400 to fix something that didn't need to be fixed. I can't swap them out myself since they are very hard to get to, up above the transmission and out of reach.

I know there are a few car nuts around here. Any ideas are appreciated.

How old and what quality are those ignition wires and did you replace ALL or just some of them? Ignition wires can't be too costly so if they're now older, start there before replacing coil packs.
You can duplicate a wet condition by misting the ignition wires, coils while it's idling. I wouldn't suggest a garden hose but a spray bottle with just water should work.
I think coil packs failing on GM cars is fairly common. If costly, can you get them aftermarket or used from a junk yard?
Btw, as for a rebuilt engine, that never includes anything besides the engine assembly itself. Anything bolted or threaded to it is reused so if old, worn, then other parts can and will fail too.

I know this engine and getting to the coil packs is a pure bitch. If you move/remove a bunch of stuff - including moving the master cylinder, you can get to it from the top.

I would do what Evil suggests and see if the plug wires are bad. After that, I would look to the coil packs/ignition module. The coil packs are bolted to the ignition module and controlled by the engine management computer.

Given your symptoms, it sounds like a water ingress/weak spark issue. You can check the resistance of the coil packs with a digital voltmeter. If they are out of spec, then they are suspect. I would definitely go with a salvage part (junkyard) for the coil pack and, if the price differential is reasonable, replace the module with coil pack. If you go that route and you have a u-pull-it junkyard handy take your voltmeter with you to make sure you get a coil pack that is within spec.

This should be a part that is easy to find and likely available across any number of GM products with engine over several model years. If you do it yourself, spend some time researching on the net, since modules from later model years may work and incorporate improvements. A junkyard will have access to the Hollander interchange data that will tell them what other model/model years will work.

I had a problem like this once with a mustang. Do you have access to a good ole fashion timing light? If you can duplicate the problem while the car is not in motion, you can monitor each cylinder individually and isolate the problem. Does the car have a mass air flow sensor? If so unplug it (I know sounds stupid) and see if the car runs better under load. Being unplugged the car will go into open loop and will no longer use the IO from the engine. If the coil packs/wires/spark plugs/fuel pump-filter are faulty, the condition will still exist even in open loop.

Key Keeper wrote:I had a problem like this once with a mustang. Do you have access to a good ole fashion timing light? If you can duplicate the problem while the car is not in motion, you can monitor each cylinder individually and isolate the problem. Does the car have a mass air flow sensor? If so unplug it (I know sounds stupid) and see if the car runs better under load. Being unplugged the car will go into open loop and will no longer use the IO from the engine. If the coil packs/wires/spark plugs/fuel pump-filter are faulty, the condition will still exist even in open loop.

If the car doesn't have a Mass air flow sensor, it will have a MAP sensor (Manifold Absolute Pressure). You should unplug this if you don't have the MAF. I once saw a bad MAP sensor cause a car to backfire.

Unplugging either of these sensors will set off the check engine light. If it doesn't go out when you reconnect the sensor, you'll have to disconnect the battery cable for about 30 minutes to clear the codes if you don't have a code scanner to clear them.

Speaking of codes, have you tried pulling pulling the computer codes? Since it's a 95, you may be able to pull them without a scanner. http://www.troublecodes.net/GM/

Good luck!

When I replaced the wires, I replaced all four with ACDelco wires. I also went ahead and replaced the spark plugs with NGK Platinum plugs.

When I replaced the plug wires, I went ahead and put a new EGR valve and fuel filter into it too.

I called the shop that did the original work to it, and they said bring it in for a free diagnostic since it's only been about 3 weeks since I originally had the work done and it technically wasn't 'fixed'.

I'm going to see what they say. If they just spew chunks, I'll be taking the car home and trying to figure out how to work on it myself. I have a friend who has a garage packed with tools, and a spare car to drive in the mean time.

Thanks for the suggestions, guys! When I get the car back I'll take a look at these things. I'm pretty sure my friend has a timing light somewhere. And I'm not sure about the mass airflow sensor. I have the Haynes manual to the car, I'll have to take a look.

And now that the fuel pump was mentioned, I do remember that I've been suspecting it's going out. The car is hard to start when cold, as if it's not getting enough fuel. If I crank it for a few seconds, it fires up and seems to do well. But every once in a while, while driving, it will decelerate a little bit, then pick back up.

Oh, only 3 weeks since a shop supposedly fixed it? That's called a "comeback" to the tech who got paid to fix your car so it better be free, at least the labor.

I suppose I should be a bit clear about something: When I took the car into the shop with the original sputtering-while-dry problem, I was told that the spark plug wires were bad and the spark plugs were fouled and worn. They also said it would be a good idea to replace the fuel filter, since it hadn't been changed in a while. So I had the shop replace them. I had already replaced the spark plugs myself and had only put about 10000 miles on them, but I had them replaced anyway since I wanted to eliminate any problems. I would have replaced the wires too, but the aforementioned pain-in-the-a$$-to-get-to coil packs prevented me from reliably pulling wires and getting them back in the right spot.

When I got the car home, I checked over the work with a fine-toothed comb. The plug wires had all been replaced with new AC Delco wires, the plugs were new NGK Platinum plugs (I had put Bosch Platinum 2 plugs in it). And the in-line fuel filter had been replaced. I also changed out the EGR valve and PCV valve myself, since the EGR valve was stuck open (or closed) and the PCV valve looked grody. And that did seem to fix my problems. At least, the sputtering-while-dry problems. It would idle smoothly, better than it had before. It took the rain to show the worst of it again.

Anyway, I should hear from the shop tomorrow morning, so I'll post back then. Crossing fingers!

MAF is an option. You can take it out and spray it with break cleaner and replace it.

Bad vacuum lines?

Got a call from the shop this morning, and since they were just down the way from my work, I headed there. They showed me the coil packs. One of them looked fine, but they said it was testing weak on the sparks. And the other coil pack had a nice crack in the casing where water was getting in and causing it to short. Two cylinders down, just like I had figured it felt like. They're charging me for parts, and half on the labor because of the come back. Ends up being $210 instead of $350.

I'm glad to hear they found something. Hopefully this fixes it.

Got the car back from the shop this afternoon. $250 later, and the car is now running great. Got the old coil packs back from the mechanics, and sure enough, one of them had a nice crack in it. That was causing havoc in the engine. Also managed to foul up the two spark plugs that were connected to that coil.

But I'm also finding out the hard way that you never let a friend drive your car 'around the block' to try to figure out what the problem is. Because he WILL drive the car through the biggest puddle he can find, and it will f*ck with things bad. Thankfully, it wasn't so deep that it flooded the engine, but water got sucked up into the belts and now my tensioner pulley is squealing like a pig. And no amount of WD-40 or PB Blaster Penetrating Oil will stop it from squeaking. New tensioner pulley go... good news is the hard starts and random sputtering were caused by the coil packs, and the fuel pump isn't going out. Yay.