Quote:
Originally Posted by marinesemperfi
I just bought this 96 blazer and knew it would need some work. Little did i know there were as many little gremlins as there are. I have been reading posts in the forum, and have figured out my fuel pump is most likely the cause of all my problems. I decided to not be a tight wad, and got the new Delphi fuel pump ordered, but it has not arrived yet. I need to know if the connectors are different on the new fuel pump, and if i will have to get the wiring harness. if it does have to have a new wiring harness, does it automatically come with the new pump, or do i buy that seperately. Also i have already had the old pump out, and found what may have been a short on the connector so i rewired it right, and figured i would test the pump again, but still have the same problems as before. Are there any tricks to getting the new fuel pump completely installed without damaging it? I only want to have to do it once.
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Good Choice on fuel pump.
But you should have run a pressure test before pulling pump.
Your parts place should ckeck and send the wiring kit if needed.
If needed always solder wiries together and seal with sealer.
WATCH TANK VENT LINES AND FUEL LINE CONNECTORS and wire connectors when installing new pump.
Also replace fuel filter with new pump and recheck filter after running a week or so.
After installing new pump run a pressure test.
4.3 W -V6
The only true test on a fuel pump old or new 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 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.
When you get new pump installed.
Post back fuel pressure readings.
Good luck