Mechanics

CHEVY ENGINE STALLS (INTERMITTENT)

2003 Chevrolet Avalanche

Engine Mechanical problem
2003 Chevy Avalanche V8 Four Wheel Drive Automatic 117000 miles

03/Avalanche/5.3L/Z71/4x4/Vin: 3GNEK13T13G118934/117,000 miles.
7-29-10 On my way to MX practice, engine stalled 3 times. Checked voltage with enigne running with no accesories on, 14 vdc. Engine running with all accessories on, high beams, seat heaters etc. 13.88 vdc. Engine off, 12.70 vdc.
7-30-10 Engine stall #4. No codes, replaced ingnition switch. Runs great.
7-31-10 Engine stall #5. Finnaly Code P1514, throughly cleaned mass air flow sensor and cleaned throttle body. Start vehicle, engine light clears, vehicle runs great.
8-1-10 Engine stall #6. Cleaned battery terminals, cleaned engine to chassis ground connections, cleaned and replaced two driver side ground bolts and lock nuts for three seperate wires, replaced fuel filter. Runs great, cant reproduce a stall.
8-2-10 No issues yahoo.
8-3-10 Stall #7 (90 miles since last issue).
Replaced fuel pump fuse, replaced fuel pump relay, replaced PCMB fuse. Checked wired harness under driver seat, no chaffing, ok. Performed Fuel pump test-A, ignition on, engine off, 60 psi for 3 seconds then drops to 55 psi.
Performed Fuel pump test-B, ignition on, engine on, pressure drops from 60 psi to 52 psi, then fluctuates between 51 - 52 psi with engine running. Stall continues to be intermittent. Is my fuel regulator and fuel pump good? Any suggestions what to try next?
Best regards, Mike Pyne +45-Mx-Vet
Avatar
Mpyne
August 3, 2010.




Blown regs usually wont cause stalling, just poor mileage and hard starting. The fuel pressure spec is too low, and can cause the stalling, should be 55-62 psi. These are very sensetive to fuel pressure and can stall/no start being just a few psi low. AT 117k it wouldnt be out of the norm to need a pump. If it feels like itis running out of fuel I would start there, a weak pump can also set mixture coodes adn MAF codes due to low flow/pressure.I would replace the fuel pump relay (underhood relay center) and the filter. Also try removing the vacuum line off the pressure reg (on fuel rail drivers side) to see if any fuel is present, if so replace it as well

Tiny
Jack42
Aug 4, 2010.


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