1997 S10 Fuel Pressure


kick-back
09-15-2007, 10:04 AM
I have a 97 4.3 pick-up and would like to know what is the nominal range for its fuel pressure. Thanks

MT-2500
09-15-2007, 10:16 AM
The specs for a 97 S-10 4.3 W or X engine is 60/66 lbs of fuel pressure.
Depending on engine load and vacuum.

No load around 61/62 or full load or pull should go to around 65/66 lbs.

kick-back
09-15-2007, 01:21 PM
My fuel pressure is running from 50psi to 58psi. How can I tell if the fuel pump regulator or the fuel pump is the cause?

MT-2500
09-15-2007, 02:51 PM
The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold and fuel pressure testing guide line.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

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