Bad bad bad BAD misfire!

[#1taho]

SOMEONE help this guy

 

[about20ninj45]

Get yourself an oscilloscope and start checking your injectors. Set your oscope to trigger on falling voltage. Observe your wave forms for any abnormalities.

 

[t_ahan]

i have the GM bible books for the GMT800's i will start flipping through pages and going through the thread and start a check list to the diag. charts in the misfire section......

i bought the books from the publisher for like $600 when i had the entire pass. bank misfiring...

hopefully i find something that we are missing here

 

[oldsman003]

Update as of today, purchased multimeter to check voltage flow to the injectors. Every cylinder missing or not reads between 7.3-7.55 rechecked spark from coils with my trusty Philips head screw driver and good spark (done know how to check voltage on them) random fire on cylinder 5 and 7 dead missing on 1 and 3 and fully firing entirely on bank 1.

 

[oldsman003]

I'm confused about the knock sensors, I have been told bank 2 could be faulty but them at the same time couldn't cause my issue. The plug that connects the knock sensor harness had no power to or from. Don't know if it is normal or not but just another piece of info for someone more knowledgeable

 

[oldsman003]

And also at any given time will run on more cylinders under some throttle than at idle. It barely runs at idle at around 350rpm

 

[oldsman003]

Update, I purchased a better multimeter to recheck my injector readings as well as my coil readings and all check out to over 12v key on power. Pin 1 and pin 40 on both pcm connectors which are grounds I checkedfor continuity and all is fine. Still misfiring constant on cylinders 2 and 4 intermittentmisfire on cylinders 6 and 8

 

[SLCHOE]

Update as of today, purchased multimeter to check voltage flow to the injectors. Every cylinder missing or not reads between 7.3-7.55 rechecked spark from coils with my trusty Philips head screw driver and good spark (done know how to check voltage on them) random fire on cylinder 5 and 7 dead missing on 1 and 3 and fully firing entirely on bank 1.

Update, I purchased a better multimeter to recheck my injector readings as well as my coil readings and all check out to over 12v key on power. Pin 1 and pin 40 on both pcm connectors which are grounds I checkedfor continuity and all is fine. Still misfiring constant on cylinders 2 and 4 intermittentmisfire on cylinders 6 and 8

I'm confused. The first quote states half are firing and half are intermittently firing yet they all firing (this would be bank 1). Your first post said you were misfiring on all of bank 2 (2,4,6,8) . Which cylinders have misfires counted by the ECM (the highest counts)? Which plugs wires are physically firing?

 

[oldsman003]

All plugs are receiving spark, highest misfire counts are cylinders 2, 4 and 6 although every cylinder is missing at some point the said cylinders are missing hundreds of times versus 12 or 14 etc...

 

[oldsman003]

Replaced o2 sensors on both banks, and new plugs on bank 2. Ran on what I feel was 7 cylinders under moderate throttle play. When I let it idle down it barely started running them continued to go on and misfire like It did before. I can remove the injector wires one by one on bank 2 worth no change in idle on cylinders 2, 4, and 6. I remove plug wires on said cylinders and see his conductivity in spark between coils and wires.