Car misfiring and shutters under boost

[bq509]

Ok where do I begin...my car ran like a dream up until recently. I own a completely stock 95 eclipse gsx with auto trans. I took it in to have a remote start & alarm installed. When I went to pick up the car I noticed my bulbs were blown out in my dash gauge bezel and a few of my taillights. I thought whatever no big deal ill just replace em. He probably just shorted something out. Well it doesn't stop there. I drove it around for a bit and all the sudden it just drops 2 cylinders and it seemed like it would only do it when it got to operating temperature.

So I drove the car back to the shop running on 2 cylinders (2&3) to have them remove their installation. Give me a refund and also compensate me for the power transistor that was shot (as I found out it wasn't my coil and that was the reason it dropped cylinders 1&4).


I replaced the power transistor and car was firing on all cylinders again with a slight misfire still and would only run smooth if I stayed out of boost. As soon as I get past 5psi the car shutters, hesitates, pops. It just feels horrible and sounds horrible. I replaced the spark plugs and wires thinking maybe running the car on 2 cylinders caused them to foul out. When I pulled them they were pretty dry. And white. (which means I'm running lean I think) and ONLY cylinders 1&4 were covered in oil but not on the firing side. On the part where the wire connects with the spark plug. Almost like I have a bad valve cover gasket/spark plug gaskets. But the problem persists...

Car is still sputtering, misfiring, and hesitating ESPECIALLY under boost after replacing the coil, power transistor, plugs, and wires. I'm about to do a compression test which, correct me if I'm wrong, should read 160 across the board right? I thought by now replacing these things would fix the problem but I fear from the car running on only 2 cylinders that it did more damage than I think. And why were cylinders 1&4 the only ones with oil? If anyone has a clue what could be causing this....like I said car ran perfect before those stupid f@*%s attempted installing a remote start/alarm. All help would be greatly appreciated. Thanks for reading!

 

[codym]

Have you done a boost leak test ? Try that and check the simple things , give the ECU a look over. If all else fails do a compression and depending on the results do a leakdowm test , pull the head and check the pistons and valves.

 

[David9er]

When I pulled them they were pretty dry. And white. (which means I'm running lean I think) and ONLY cylinders 1&4 were covered in oil but not on the firing side. On the part where the wire connects with the spark plug. Almost like I have a bad valve cover gasket/spark plug gaskets. But the problem persists...

White plugs are a tell tail sign that you are burning antifreeze, most likely this is due to a head gasket. Do a compression test to verify.

 

[GST with PSI]

Ok where do I begin...my car ran like a dream up until recently. I own a completely stock 95 eclipse gsx with auto trans. I took it in to have a remote start & alarm installed. When I went to pick up the car I noticed my bulbs were blown out in my dash gauge bezel and a few of my taillights. I thought whatever no big deal ill just replace em. He probably just shorted something out. Well it doesn't stop there. I drove it around for a bit and all the sudden it just drops 2 cylinders and it seemed like it would only do it when it got to operating temperature.

So I drove the car back to the shop running on 2 cylinders (2&3) to have them remove their installation. Give me a refund and also compensate me for the power transistor that was shot (as I found out it wasn't my coil and that was the reason it dropped cylinders 1&4).


I replaced the power transistor and car was firing on all cylinders again with a slight misfire still and would only run smooth if I stayed out of boost. As soon as I get past 5psi the car shutters, hesitates, pops. It just feels horrible and sounds horrible. I replaced the spark plugs and wires thinking maybe running the car on 2 cylinders caused them to foul out. When I pulled them they were pretty dry. And white. (which means I'm running lean I think) and ONLY cylinders 1&4 were covered in oil but not on the firing side. On the part where the wire connects with the spark plug. Almost like I have a bad valve cover gasket/spark plug gaskets. But the problem persists...

Car is still sputtering, misfiring, and hesitating ESPECIALLY under boost after replacing the coil, power transistor, plugs, and wires. I'm about to do a compression test which, correct me if I'm wrong, should read 160 across the board right? I thought by now replacing these things would fix the problem but I fear from the car running on only 2 cylinders that it did more damage than I think. And why were cylinders 1&4 the only ones with oil? If anyone has a clue what could be causing this....like I said car ran perfect before those stupid f@*%s attempted installing a remote start/alarm. All help would be greatly appreciated. Thanks for reading!

As far as doing a compression check, CLT, or BLT? Sure, those are all good things to check. I doubt, however, they are going to be the root cause of your problem. Think about it? If the car was running perfectly before the shop touched it, then a mechanical issue like low compression or a leaking intercooler pipe aren't going to be the reason why your car runs like ass. That is, unless your issue and the shop's work are unrelated, and they didn't cause your issue at all. Wiring in a remote start system is electrical, and in the electrical system somewhere is where your problem will be. The shop probably caused some electrical issues, no doubt, but your oil leak issue is probably completely unrelated.

Start with the oil leak. If the plug tops are wet, and the tips are dry, that means you have a leak into the plug well. Pull the valve cover and replace the valve cover gasket. Specifically, make sure the gaskets isolating the valve cover from the plug wells are replaced.

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Now, your larger issue is more complicated. You need to figure out where the shop was hacking up your harness. I would return to the shop, and have the show me directly where they were modifying the harness. That way, you have a place to start chasing the harness.

With no other guidance, I would start by checking the harness at the ECU. Look for wires crossing, and anything that seems abnormal. Then, look under the drivers side dash at the ignition harness, and make sure there is nothing abnormal there. Make sure powered positive circuits are not going to ground. Do you have a service manual with wiring diagrams?

Lastly, I would be prepared to replace the ECU. The symptoms you are describing aren't too different than those of a car with a bad ECU. If you are replacing ignition components to no avail, there's likely a larger issue at hand. Is there someone in your area who has a good ECU they could let you swap into your car? Since you have to pull the center console panels to inspect the harness going to the ECU, I would just pull the ECU and open the case. Look for any sign of burned circuits, or leaking capacitors.

Leaky caps:

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Toasted ISC drivers:

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[David9er]

As far as doing a compression check, CLT, or BLT? Sure, those are all good things to check. I doubt, however, they are going to be the root cause of your problem.

Your probably right, it won't be the root problem. I would still do those tests because that is a bad sign from the plugs if they are white.

 

[Mischif]

+1 on replacing the valve cover gasket and spark plug well orings. Oil in the spark plug well can cause the spark plugs to fire inside the wells instead of the combustion chamber. Boost will cause the spark plug to fire inside the well more constantly when there is fluid collected in there.

 

[bq509]

So I replaced the spark plugs, wires and everything ignition related yesterday. Then today I pulled the spark plugs to check if oil got in there again. Yes there was oil especially in cylinder 1. and my valve cover actually has a small hairline crack right next to cylinder 1. Also the gaskets are BAD. SOOO I will be replacing the gaskets and valve cover tomorrow. Since I cleaned everything out my car is running beautifully again! Its definitely the valve cover and gaskets. Glad I found out the problem and it wasn't something more serious. Thanks guys!

 

[GST with PSI]

So I replaced the spark plugs, wires and everything ignition related yesterday. Then today I pulled the spark plugs to check if oil got in there again. Yes there was oil especially in cylinder 1. and my valve cover actually has a small hairline crack right next to cylinder 1. Also the gaskets are BAD. SOOO I will be replacing the gaskets and valve cover tomorrow. Since I cleaned everything out my car is running beautifully again! Its definitely the valve cover and gaskets. Glad I found out the problem and it wasn't something more serious. Thanks guys!

So, did you even need to replace any of those ignition components?

 

[bq509]

Well I never had to check the ecu. What was going on in the beginning was my power transistor went out. So I replaced it and it fixed the two dead cylinders issue. But I was still getting an intermittent misfire. So I changed just the plugs (because my old ones werent that old) & I figured I needed to in order to figure out the issue. Found that Cylinder 1 had a lot of oil on it and the whole area under the sparkplug cover was drenched in oil. Well when i replaced the plugs I didn't bother to replace the wires because I just bought new plugs & wires on my last oil change. Anyways, the plugs didn't fix it so I went to go pull the plugs to check them again for oil and when I went to pull the wire out on cylinder 1 the thing completely crumbled apart. Like I pulled up on it by the base of it and it tore and it was garbage. So I bought wires...cleaned everything up. Now it runs fine again.

It was an electrical issue but caused by leaky valve cover. Oil all over everything = ruined parts and cause of non functioning plugs/wires.