95 blazer starting problem
eastsidereefer
08-03-2008, 07:36 PM
I have a 95 blazer. the only way to start it is to prime it with starting fluid. it will run. but when i kill it it will not startup unless i prime it again with start fliuld. I change the fuel flilter. I see that the the fuel pump is pumping gas. but i really can not hear the fuel pump when i turn the key on. Thanks eastsidereefer
MT-2500
08-04-2008, 10:05 AM
Time to check and verfy good fuel pressure.
Even 3-4 lbs low will give a hard or no start.
4.3 V6 W or Z engine code?
Even 3-4 lbs low will give a hard or no start.
4.3 V6 W or Z engine code?
eastsidereefer
08-04-2008, 11:47 AM
Just checked it. 41lb. could it be the fuel pump?
MT-2500
08-04-2008, 12:27 PM
W engine code?
YOU NEED TO DO SOME MORE TESTING TO FIND OUT.
Like.
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 or hot and fuel pressure testing guide lines.
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 pressures.
Cold start should be 64-65 lbs of pressure.
The 95 or yours is 55/61 lbs 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 55/61 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post-back fuel pressure readings.
Remember a fuel pump pressure regulator controls the pressure and maintains a steady pressure depending on engine load and vacuum.
It has to be capable of producing higher pressure than the regulated pressure.
The fuel pressure controls pressure and can leak off or bypass pressure
Post back all fuel pressure readings you can do.
MT
YOU NEED TO DO SOME MORE TESTING TO FIND OUT.
Like.
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 or hot and fuel pressure testing guide lines.
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 pressures.
Cold start should be 64-65 lbs of pressure.
The 95 or yours is 55/61 lbs 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 55/61 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post-back fuel pressure readings.
Remember a fuel pump pressure regulator controls the pressure and maintains a steady pressure depending on engine load and vacuum.
It has to be capable of producing higher pressure than the regulated pressure.
The fuel pressure controls pressure and can leak off or bypass pressure
Post back all fuel pressure readings you can do.
MT
blazerbob91
08-05-2008, 01:56 AM
Will a bad nut kit also cause this starting problem?
MT-2500
08-05-2008, 09:20 AM
Will a bad nut kit also cause this starting problem?
If it has one and if it is leaking off pressure yes.
You need to run the full fuel pressure test to check pump and fuel leak off.
MT
If it has one and if it is leaking off pressure yes.
You need to run the full fuel pressure test to check pump and fuel leak off.
MT
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