Misfire/Backfire...Idles like crap

[Backinajiffy12]

Hey guys

The car has been having a small idle surge from 500rpm to maybe 1500rpm

I was driving home friday from work and was under light acceleration and the car would jerk. So I when and replaced the spark plugs (gapped at .028). and It drove home just fine. Had a few pops but no jerks idle was better. "Did pull p0136 before I drove it home, deleted it, didnt show up when I got home.

Started it this morning and crap idle was back and I could hear the misfires. So I shut it off and check for codes....nothing. Let it warm up was backing out of the drive way and big backfire.

So my Question is what is causing all this. Boost leak, vac leak, bad injector, running rich???

Help shes my DD

 

[GRAVEDIGGER]

How about wires? How old are they? How do they look? Might be a good idea to replace them too if you don't know the last time they were done, or it's been a while. Would be a good time to do a boost leak test too.

 

[Backinajiffy12]

Did a boost leak test last night. 1 or 2 injector seals were shot to shit, replacing all 4 after work. Biss screw was leaking cant get it out, so how do I fix that one? any other thoughts?

 

[RayBan GST]

take out the Biss with double tape , put the double tape on the screw driver and stick it out . done it so many times.


1- check your gap again and check the wires
2- make sure all the boost leaks are fixed
3- check your injectors ( pull the connectors one by one and check for engine reaction)

 

[LaserRS92]

Any cel's on the dash? Possible coolant temp sensor, fouled out plugs from leaking injector seals, leaking ecu?

 

[Backinajiffy12]

nothing on the dash, I did pull P0136 (o2) cleared it and has not shown up, replaced plugs with
BPR8ES, changing those to 7's tonight (gapped correctly). Ill look at my coolant temp sensor, it wasnt over heating or anything. And I havent checked the ECU yet.

Ok so last night I replaced all the injector seals, and did a boost leak test....Fixed the leak. Might have a small one where the J-pipe connects to the turbo. Sent to start and got the firing order mixed up, fixed it and the car started up. It idled like grap and was on constant misfire. while it was running pulled off the injector plug-in injectors 3 and 4 were not firing. Pulled all the plugs they are black and some wet (rich). Did I foul out the plugs when I messed up the firing order? Whats going on now?

*I did remove the BISS screw and replaced the O ring at 2 turns out.

 

[Backinajiffy12]

Date: 6/14/2012
Hey guys I got an update for you. So last night I went and got a compression tester. It was going great until I got to cylinder 3. My compression was 155 30 141 152 the 30 became 40 when I did a wet test. So I am in the process of removing the head, and will determine what exactly it is from there. Ill heep you guys updated.

 

[Backinajiffy12]

Ok so another update. I got the head off last night, and as you can see cylinder 3's valves just dont look quite right. The piston and cylinder itsellf are fine. I havent done any tests to so see if I fried the rings.

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[Backinajiffy12]

Melted valves...? Any input as to why this happened? Pistons are fine everything else is fine. what should be my next steps?

 

[con57]

timing could be off. pre-detnation can melt up calves. havve you ever changed your timing belt? if you have adjustable timing gears you might have them set too advanced in your timing.

 

[Calan]

pre-detonation can melt up calves.

... and nothing is worse than melted calves.

 

[Backinajiffy12]

this motor had a full rebuild 30k ago, i have never messed with the timing. I do know I had an intermitten injector on this cylinder. If that injector went out, and that cylinder was running hot would this be the result.

melted calves.

Very few things are worse than melted calves!

 

[Backinajiffy12]

I got 2 new exhaust valves and I am sending the head off to have a valve job done at import. Hopefully have everything back a put together and be up at BIR by saturday afternoon!