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misfire unsolved

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learnAsUGo

New member
So everytime i fix this car another goes wrong. This time i changed the wheel bearing cuz alignment shop told me they were bad. Drove to town that night, bout 45 minute round trip. Car temperature was acting weird, climbing then falling back to normal temp. On the way home I felt like feeling the power in the car one more time so I punched it and climbed to bout 100 before backing off. Temp at that point stayed high round about 245/250 i was only ten minutes from my house and the temp wasn't in the red so I continued to drive trying to make it home but watching it carefully. When i got home i noticed the smell of burnt antifreeze. The next day i fixed the whole antifreeze leaking problem I had apparently forgotten to close of the bleeder to the thermostat housing. But when i scanned my car the code came up for misfire on cylinder 4. I checked the plugs and wires by moving them around and the misfire never moved. My next door neighbor told me it could possibly be the fuel injector. I changed that this morning and cleared the code from the computer to see if it would come back. The car still idles rough and it has a pending code for cylinder 4 misfire. What other things would i need to fix.?
 


The busted piston skirt. Rent a borescope and take a look in the cylinder.

cylinder #4 as I was just telling another person is the hottest of all cylinders. Being that your coolant reading was probably low with air in the system, it's likely you hurt the piston since the misfire won't go away.
 
ok this is where your going to have to bear with me. This deep in the engine i'm not sure about everything. I've been told by the guy that helps me work on my car that this could be a warped or cracked head, valves, piston ring, and he agreed about the piston skirt. Now if i rent this borescope what am i looking for in they cylinder. Cuz i would much rather not replace anything i don't need to. How can i tell which one of these problems is the one i have.
 
one things i wanted to mention is that for a few days before this happened i had a code come up p1441 which said evap purge during non flow...could this have anything to do with it
 
Oh yea it sure could.

Ok, I mistyped a little. I meant to say piston landing, not skirt. The skirt is the bottom of the piston, our pistons tend to chip off the top area, right above the first ring.

The guy helping you work on the car sounds like he knows cars in general. Which is good/bad. The boosted 3800 like anything else has specific things that usually happen and other things that simply never happen.

Our motors aren't known for buring valves, head gaskets (probably got a better chance of being struck by lightning), while our heads often crack between the valves, it's unlikely that you are seeing any fallout from it.

By getting a scope in the cylinder, you will be able to see if the piston is chipped, might see a crack between the valves etc.
 
Do a compression check. If that cylinder is low, it's going to have to be torn down to fix anyway. If the landing is broken, lower compression will be seen and there's a chance the broken off piece has damaged something else, ie-valves, compression chamber.
 


would any of that stop the car from running. because i can start the car and it'll run and all i just don't want to drive it in case the misfire will hurt something else. It just sounds like the stuff you just said would stop the car from running. Just trying to make sure we on the same page you know.
 
Our cars will run on about 3 cylinders. They just won't have enough power to move. Being down a cylinder usually doesn't hurt power too badly. If you have KR from it...that pulls timing and timing is power.

I've seen a landing chip off w/o hurting the rings, it's the rings that hold your compression. Most of the time though, I agree...compression would be low.
 
to give everybody an update. I did a compression test on cylinder 4, and sense i didn't have the number it should be so i tested cylinder 3 as well. #4 was 120 and #3 was 122 so i deemed that as nothing was wrong with my compression, which i don't know whether something wrong with my piston would hurt my compression or not. I then tested my spark for 4 against 1 since they are on the same pack. I noticed noticeably more orange spark in 4 wires compared to 1, and then i compared to 2 which was the same as 1. So i figured i'd changed out my coil pack since it was only 25 bucks. It seems to have worked since when i scanned the car even the pending code for cylinder 4 misfire disappeared.

Now my other problem would be there is a very rough vibration. Now i know a bad alignment can cause vibration but i wasn't sure if that was only while moving the car or not. I know the car needs an alignment cuz i had to change out the drivers side steering arm. Any ideas about this problem would be appreciated. As for the misfire i will let you guys know tomorrow whether or not it was a delayed response from the computer after i get back from work.
 
For the vibration start a new thread. Someone that knows about suspension might not look in a thread labled misfire and you want to leave this one for other people to see.

In your diagnosis, you said you swapped wires around. Doesn't sound like you swapped them in the same way I thought you had. I figured you meant you swapped them at the coil to the other post. That way you'd have eliminated the coils, wires and plugs.

Looking forward to your suspension thread. Try and be as desriptive as possible.
 
sorry about that. i only checked the plugs and wires didn't think about the coil packs because my original thought would be 2 cylinders would be misfiring if it was the coil. but towards the end i realized that my other car...which is a hyundai accent but i figured the coils would work the same...only misfired on 1 cylinder when my coil had cracked so i checked the coil and it seemed to be the problem. and yes i will post the vibration in a new post after i drive it today to get more of a feel of what it is.
 


Yeah, logically speaking both should get effected. However I've seen an ICM not fire for one of the two cylinders, coils losing one post only. Oddball stuff can happen and glad you found it.
 
ok so back to square 1.....as soon as i put the car in reverse and started backing out of the driveway the light came back on and is misfiring on cylinder 4 still. So my question is if the piston landing or something is cracked wouldn't that mess up compression on cylinder 4. If it would then i have no idea what this could be cuz like i said before compression is 120 on cylinder 4 and 122 on cylinder 3 so i would say compression is fine
 
just to make sure it still has accurate results to what i was looking for. I did the compression test on a cold engine, with all spark plugs in except the cylinder i was testing. for both cylinders i started the car 2 times before reading the meter. I was just reading bout different ways its supposed to be done but i figure if it was low compression it would be different than cylinder 3 either way right?
 
The consistency of your test is good. The numbers you see suck, but can be based on the incorrect testing method. I've almost always found compression in teh 180 ballpark. But if you did two cylinders and got the same basic thing.. close enough.

I think I may have mentioned that a compression test is not going to 100% answer your question as to what is wrong. Make your choice, pull a head gasket or rent a borescope to find out if something else is wrong in that cylinder.
 


just to let u guys know...it turns out with the testing of a noid light on the injector harness and swapping my brand new injector to another cylinder that i needed a new injector....thank God for warranties but thank you guys for your help much appreciated
 
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