Random Misfire Issues - Sometimes will be ALL cylinders, other times just #4-6 (1 Viewer)

[alia176]

I've already done the job, I was just asking what you removed/replaced during your VC change. I'm still working though some electrical troubleshooting and found more than one injector harness wire with cracked insulation from moving it around.

Seeing if yours could also be electrical.

My reply was directed at WhiteFJ80, sorry about any confusion.

 

[Jefe23]

Well, well, wellllllll... Look what I found. I had a very strong feeling that it was a stuck valve - I was just wrong on which side. I was originally thinking exhaust, but it looks to be a stuck intake valve on #4. Why, I'm not sure just yet, but will grab a scope and see what I can find. I know that injector was stuck open and dumping fuel into the cylinder, hopefully it didn't do any more damage to the piston and rings.

Guess it's time to pull the head, but I might pull the intake cam first to see if I can get this unstuck.

Also, don't mind the exposed wire run in the background of the picture. Everything is good to go, I just need to add some split loom, tape it up, and it will be good to go.

 

[fsung]

I had random misfired issue a while back (running silky smooth for 1 day and ran like crap the next day). Checked pretty much everything, and it turned out the wiring loom for ECU behind the glove compartment was rubbing against the support bracket, the wire for injector was shorting out. Pretty easy to check before pulling head.

 

[Jefe23]

Well... I found out what was causing my #4 intake valve to stay stuck open and wanted to close the loop on this thread.

I really don't know how this happened because I didn't think these dowel pins were easy to remove, but sure enough, one came off and dropped into the head right above the valve. I didn't know until I removed the lower intake.