1991 Chevy S-10 No fuel at injectors for start.

CELIFF

MEMBER
1991 CHEVROLET S-10
6 CYL
2WD
AUTOMATIC
170,000 MILES

91 S-10 won't start, good spark, no fuel from injectors. Fuel pump comes on when key is turned. Will start and run with fuel sprayed in throttle body while startng. While running there is good fuel from injectors, just no fuel for starting?

10 Replies

JACOBANDNICKOLAS

CERTIFIED MECHANIC

When you turn the key to the run position, do you hear the pump come on? Have you checked the relay?

Let me know.

Joe

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Monday, March 8th, 2010 AT 11:50 PM

CELIFF

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Yes the pump spins up for a couple seconds. Gauge reads 12 psi, manual says 9-13 psi.

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Tuesday, March 9th, 2010 AT 6:33 PM

JACOBANDNICKOLAS

CERTIFIED MECHANIC

Are you getting power to the injector when the key is in the start position?

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Tuesday, March 9th, 2010 AT 10:12 PM

CELIFF

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11.8 volts on both red and white wires

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Wednesday, March 10th, 2010 AT 6:19 PM

JACOBANDNICKOLAS

CERTIFIED MECHANIC

If you are getting power to the injector in the start position and fuel pressure to it, the only thing I can say is the injector must be bad. Just no fuel for starting?
Inspect. And test the fuel pump relay and the fuel pump/oil pressure sending unit.
The fuel pump relay primes the system for 2secs, when engine start cranking and oil pressure goes over 4psi the fuel pump and oil pressure sending unit powers the fuel pump at all times.

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Thursday, March 11th, 2010 AT 10:00 PM

CELIFF

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And if I start it with a spray of fuel or starter fluid it runs and the injectors spray fuel in the trottle body. They just won't spray while starting? What would cause that? I can hear the pump spin up for 2 secs when the key is turned. I did the fuel pump relay check from the Haynes manual; "Idle at normal operating temp, disconnect the fuel pump relay. If the engine stops the oil pressure switch is faulty." When I disconnect the relay the engine continues to run. Oil pressure reads 40 psi while trying to start and 10-15 running at operating temp.

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Thursday, March 11th, 2010 AT 11:42 PM

JACOBANDNICKOLAS

CERTIFIED MECHANIC

The only thing I can say is the injector itself or the PCM. Inspect and test the coolant temperature sensor-

Here's the catch. Will start and run with fuel sprayed in throttle body while starting. While running there is good fuel from injectors

If there's a problem with the computer ground drivers I don't think it will continue to run after you prime it-

Sounds like the computer ground drivers for the injectors is defective or no ignition reference signals being receive by the computer and not synchronizing the injectors

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Friday, March 12th, 2010 AT 7:48 AM

CELIFF

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Swapped out ECM, no change still won't start. Starts after manually spraying fuel in the throttle body. Runs for 5 minutes then dies. Temp sensor looks good, cleaned, measures 3.4 ohms? Is that ok? Can't find reference for it. Pressure gauge reads 12 psi, manual says 9-13 psi Yep 3,400 ohms, on a cold engine. It was a auto-ranging meter, I read it wrong. If the temp senor is good what else could it be?

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Wednesday, March 24th, 2010 AT 7:42 PM

CELIFF