07 Suburban 5.3 miss on #1 & 3
#1
07 Suburban 5.3 miss on #1 & 3
Hey all, so I've got a 07 suburban with a 5.3 with the unfortunate afm. It has a constant miss on cylinder 1 and 3 I've swapped coils, wires, new plugs etc and nothing changes. Checked compression on them and #1 is around 120-125 and # 3 is closer to 150. I'm getting fuel bc the plugs are doused in fuel, number one is also covered in oil... I hear this is normal for afm vehicles. I dont think im getting spark at them but its hard to tell bc its got some weird boots that do not fit a tester and I can't get the plugs to spark by holding them against the exhaust. Looking for insight in something I may have overlooked or anything really at this point. I need this truck so I really can't afford to have it sitting.
Thanks!
Thanks!
#3
If you do have power to the coils, with a test light connected to the battery positive terminal place the pointed probe in the other wire connector of the coil that is not firing and crank the engine , the test light should blink everytime the PCM grounds the coil. If not , verify wiring from PCM is complete to the coils in question. If no fault found in wiring ,
Good chance , PCM has a problem.
Good chance , PCM has a problem.
#4
I’ve checked power I’ve got 12v on supply, 12v on signal, and 1v on low reference on both. The only thing I can think is pcm isn’t cycling the signal on and off to actually fire the coil.
#6
I thought that too at first but all 8 coils ground at the same spot so if I still have 6 working fine I find it hard to justify being a contortionist to try and get at the ground being it’s blocked by the front diff. I have power at the coils they just aren’t being commanded on/off and I definitely have fuel the plugs are soaked.
Thread
Thread Starter
Forum
Replies
Last Post