P0172 95 4.3 vortec running rich need help
Thread Starter
CF Beginner
Joined: Sep 2018
Posts: 17
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That was just a screen shot taken with the KOEO. I don’t have the truck with me tonight. Drove the wife’s car to work. Monitoring the sensors while driving the past few days the advance is always negative usually-20 to -35 CYL #1. I’ll screen shot it when I get a chance.
CF Senior Member
Joined: Aug 2018
Posts: 357
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From: Adirondacks,ny
Max is 25% either way,+or-,so a uncontrollable problem, not sensor related, something out of the pcm's grasp,fuel being sucked in from fuel pressure regulator vac.line?evap. canister fuel soaked?tps reading to high?
Thread Starter
CF Beginner
Joined: Sep 2018
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pressure regulator is inside of the plenum and uses a small hole in the shell for manifold vacuum and it isn’t leaking. Tested it three times now. I took the vacuum line for the fuel canister off to isolate it from the system thinking it was sucking to much fumes in on the purge cycle. Even isolated from that from the system it popped the code. Injector is not leaking. Poppets aren’t leaking. Fuel lines inside of plenum aren’t leaking. Used propane around plenum and upper manifold to see if it had any vacuum leaks. Nothing. I’m starting to question the Vehicle control module (PCM) on this truck wondering if it’s bad.
Thread Starter
CF Beginner
Joined: Sep 2018
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This is what the inside of the plenum looks like. The CFI spider is located inside the intake plenum along with the spider fuel lines and pressure regulator. It’s an all in one unit. Mine is new and been in for around 15 months.
