cylinder 1 missfire... may be a bigger problem.

[jshuman]

hey guys,
I dont know where to start with this. I will try to be as detailed as possible. A few weeks ago, I noticed a stutter/ missfire during the 5k-7k rpm range. After about a week, my idle began to rise above the dsmlink set idle of 900rpm to 1200-1500rpm. I bagan to notice the miss at lower rpms and at idle as well. Also, I would see occasional puffs of smoke at an idle. I ran the DTCs on the DSMlink which came back with three codes instead of the usual two. The code was 0301; missfire detected in cylinder #1. I pulled my spark plugs and inspected them, including the gap. They were fine, but i replaced them with the same NGK7s plugs anyways, just to rule that out. I have also checked the magna core plug wires, which were also fine. It seems that neither plugs nor wires are my problem. I also did not suspect the coil pack since only one cylinder is missfiring. Tonight i tried switching wires around to see if i got a miss in another cylinder, but there was no change. Also, after letting the car run for a couple minutes, I pulled the spark plug in cyl. 1. A thin stream of smoke started coming from the opening. I am not sure if that is normal? Does anyone know what could be causing these symptoms? I am going to run a compression test tomorrow.... I will post my numbers afterwards. Is there anything else I should check... injectors, injector connectors etc.? Oh, the car is pretty heavily modded, let me know if you have any questions about the mods. Any help would be greatly appreciated.
Thanks ahead of time!

 

[jshuman]

Ok here are the numbers from the compression test I did tonight.
#1 120
#2 147
#3 120
#4 147

this is on a 6 bolt motor. .020 over w/ wiseco pistons.
Could these numbers be the cause of the missfire? If so, why am I only pulling a code for cylinder one and not three?
Any ideas?

Thanks again!

 

[Shadow98]

You compersion isn't that great, but still fine. Make sure the injector connector is on tight. You might not be getting fuel to that cyclinder.

 

[jshuman]

Thanks, I am going to check all of the injetors tonight. As far as the compression is concerned, should i be worried about those numbers (head gasket?)? Are there any other tests I should run before going any farther.
Thanks again!

 

[jshuman]

I read some other posts on compression numbers and realized I had not performed an accurate compression test. Here are the new numbers:
1: 147
2: 147
3: 150
4: 147

I thought these looked much better, and I dont think compression is the cause of the missfire in cylinder 1. I decided to pull the injectors last night. The connector for cylinder 1 had bare places on the wires, but the other 3 looked fine. As far as the injectors, a few drops of fuel came out when I pulled 2,3, and 4, but not from number one. Does that mean anything to anyone?

 

[FORMONTOYA]

The bare wires on the harness for injector 1 is probably the problem as it can allow the circuit to short-out thus not "firing" that injector. I would repair the harness at the very least and see what happens.

 

[jshuman]

The bare wires on the harness for injector 1 is probably the problem as it can allow the circuit to short-out thus not "firing" that injector. I would repair the harness at the very least and see what happens.

Thanks. That makes sense to me. Could you tell me the best way to go about that? Should i just wrap the wires or should I replace the harness? I would really appreciate it.

 

[Gregory]

I have a similar problem. Did you ever figure this out?

 

[GSXeclipsePSI]

What would be the best solution for repairing the injector plug. Mine are bare to close to injector plug where is best place to buy the ends?

 

[90T5I]

Well most injector connectors are the same if its the connector thats bad go to a salvage yard and just find one that looks close. make sure u cut with plenty of wire to work with. then just solder the wires together then heat wrap them to clean everything up. hope that answers your question.