Helping a friend get a 92 Blazer up and running - we got it to start but CEL was on and ran rich. It idled nice and strong. Jumpered the ALDL, got a code 33. Before I went on a parts cannon approach, I checked the MAP sensor - it was plugged in but the vacuum line was somehow disconnected. Reconnected the line. Truck isn’t running rich, CEL is off but the idle is rough.
The truck has new wires, cap/rotor, plugs. New fuel filter too - Ecogard from Amazon. Sprayed the vacuum lines, TBI to manifold flange and all along the intake for vacuum leaks. None. I stumbled across this post:
Went to the parts store, grabbed a fuel pressure test kit, I have 9psi of fuel.
Now, this truck was sitting for a while. I measured fuel pressure before the filter. A part of me wants to check the injectors before I condemn the fuel pump but there’s also the possibility CA’s ethanol-blended has simply phase-separated, water dropped out and rusted the fuel tank which also clogs the filter sock with rust. What should I check for next?
The truck has new wires, cap/rotor, plugs. New fuel filter too - Ecogard from Amazon. Sprayed the vacuum lines, TBI to manifold flange and all along the intake for vacuum leaks. None. I stumbled across this post:
1990 5.7L TBI surging idle, lacks powers and runs better with MAP unplugged - Chevy Message Forum - Restoration and Repair Help
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Went to the parts store, grabbed a fuel pressure test kit, I have 9psi of fuel.
Now, this truck was sitting for a while. I measured fuel pressure before the filter. A part of me wants to check the injectors before I condemn the fuel pump but there’s also the possibility CA’s ethanol-blended has simply phase-separated, water dropped out and rusted the fuel tank which also clogs the filter sock with rust. What should I check for next?