fouling #2 plug and misfire

[DSMcamaro]

1992 Turbo AWD automatic, basically stock. Running NGK BPR6ES plugs. The #2 plug fouls out about once a week. I checked the compression and its normal. It has spark but I have tried different ignition module, coil pack, and wires anyways. It randomly misfires on the #2 cylinder. The car had 450cc injectors in it when I bought it but I found some 390's and put those in. Had the 390's in for about 3,000 miles and thats when it started to foul the #2 plug. So i change the #2 injector to a 450cc injector and it still does the same thing. Any ideas? The plug comes out black and dry. I bought another set of 390cc injectors but the guy shipped them to the wrong address, so I probably wont have them for another week.

 

[DSMBOOTIN32PSI]

Yeah See The First Thing That Popped It My Head While I Was Reading Was Injector But See If It Has Injector Pulse Or Hook A Noid Light Up To It Or Go To The Auto Parts Store And Get A Injector Pulse Gun There Cheap Small See Through And Have A Metal Rod On Them And If And When U Get Noid Light Or The Gun Start Car And Put It To Each On It Should Beep And Flash Like Crazy If It Works Or Even Easer Thing To Do Start Car And Unplug The Injector And See If It Trys To Die Cause If It Does Then Its Nothing To Do With That Butif Not It Is A Injector Or Has A Bad Wire Hope That Helps A Little

 

[Shady1687]

if you have replaced the injectors and the same problum happens i would assume that that probaly isn't the problum. At first i though a rich air fuel problum but it is in only one cylinder .... so i would say maybe check the cylinder number 2 spark plug wire and coil pack to see if it is fire the plug properly..............

 

[Shady1687]

hahaha sorry its late i didnt see you said you already tried that

 

[Shady1687]

anyways i dont no if i understood you correctly but you said you put a 450cc injector in cylinder 2 and left the 390s in the rest. for future always run all the same injectors.

 

[DSMunknown]

Yeah See The First Thing That Popped It My Head While I Was Reading Was Injector But See If It Has Injector Pulse Or Hook A Noid Light Up To It Or Go To The Auto Parts Store And Get A Injector Pulse Gun There Cheap Small See Through And Have A Metal Rod On Them And If And When U Get Noid Light Or The Gun Start Car And Put It To Each On It Should Beep And Flash Like Crazy If It Works Or Even Easer Thing To Do Start Car And Unplug The Injector And See If It Trys To Die Cause If It Does Then Its Nothing To Do With That Butif Not It Is A Injector Or Has A Bad Wire Hope That Helps A Little

We have rules about posting properly. Follow them, please. They are called "periods". Please use them appropriately. There is not one single period in that whole bunch of BS. Stop capitalizing the first letter of every single word - it's annoying. And "U" is not "you".

 

[MrBoxx]

Thank you, Anthony.

DSMBootin32psi, please follow his suggestions.

 

[DSMcamaro]

Yes, I put the 450 in for testing purposes, like I said, I have some different 390's on the way. Are the wires that go to the injectors switchable? I'm thinking it may be electrical.

 

[DSMcamaro]

Seems like it may be temperate related. Once it gets up to full temp it seems to run better. Also forgot to mention originally that I do have a rebuilt ECU so that shouldn't be the problem. Also, I put all the 390cc injectors back in and sometimes it runs fine and sometimes it misses.
Any help please, this is driving me crazy.

 

[DSMcamaro]

Still dealing with this. Any help would be greatly appreciated. It also seems to run better when its above 3,000 RPM but that may just be because its harder to hear at higher RPM's.

 

[turbotalawd]

When you pulled the #2 injector did you notice if the cap was cracked at all? Im talking about the 390cc one not the 450cc. Is the injector seal on that cylinder in all the way? Did you check for any boost leaks?

 

[DSMcamaro]

I've done a boost leak test and it tested fine. I've swap the injectors around to see if it would follow the injector but it didn't. I've had 3 different injectors in the #2 cylinder and it always fouls #2.

 

[turbotalawd]

It sounds like a ignition problem then. Check the resistance on the plug wire. Could be the wires.

 

[DSMcamaro]

I've switched plugs/plug wires around, tried a whole different set of plugs, change coil pack and ignition module.

 

[turbotalawd]

Is the spark plug gapped correctly?

 

[tbonitz301]

I know you said you had the ecu rebuilt, but if youve tried everything else i would swap ecu's with a friend, and see if your problem follows the ecu.

 

[DSMcamaro]

Is the spark plug gapped correctly?

yes

I know you said you had the ecu rebuilt, but if youve tried everything else i would swap ecu's with a friend, and see if your problem follows the ecu.

If I had one to try I would.




New info....I tried a different MAS and it ran fine for about a min and then started missing again. It did the same thing once before when I disconnected my battery overnight. Ran fine for about a min and then started missing again.


thanks for the help so far guys, keep the ideas coming.

 

[tbonitz301]

Maybe your ecu is fryin components.I dont know. dont listen to me

 

[turbotalawd]

Did you get those other injectors in yet? Make sure you change out all the o-rings and gaskets when you put them back in.

Edit: What were the compression numbers between the cylinders?