2000 Blazer Fuel Pressure

[kjrakes]

Does anyone have the factory specs for fuel pressure of a 2000 Blazer? I am having a hard start issue and suspect a fuel pump problem. Pressure readings from my pressure gauge read 57 psi with key on, engine not running. With engine running I am getting 55 psi. Anyone have the factory specs??

[rlith]

That falls within factory specs... 55-59 for the 96+ How long does it hold pressure after you turn it off?

[kjrakes]

Where did you get the specs from?

[blazee]

The answers to most questions (as well as the rules of the forum) can be found in the sticky at the top of the forum titled: FAQ and How to's Inside! READ ME BEFORE POSTING!

The answer could have been found in this thread: 96+ Hard Start, No Start, Rough Idle Info


The spec is 60 - 66 psi. The original repair manuals stated 55 - 60 psi, but this is incorrect:

[rlith]

Oops, my bad... I was using the specs from the manual on my desk... Guess I need to pay attention myself..

[MT-2500]

Originally Posted by kjrakes

Does anyone have the factory specs for fuel pressure of a 2000 Blazer? I am having a hard start issue and suspect a fuel pump problem. Pressure readings from my pressure gauge read 57 psi with key on, engine not running. With engine running I am getting 55 psi. Anyone have the factory specs??

If you have a 4.3-5.0-5.7
Here is some guide lines. Even a couple of lbs low will give you a no or hard start. And always watch for a fast leak down on pressure.
Also make sure your gauge is accurate and run it for 30 minutes or more for a good hot fuel pump check.
Hard to start cold.
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.
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.
Post back fuel pressure readings.

[Bodaggit]

I've always wondered why they made it so these vehicles had to have such a high fuel pressure.

Looks like they would have been able to make it run on much less pressure, and solved a lot of fuel pump related issues.

[MT-2500]

Originally Posted by Bodaggit

I've always wondered why they made it so these vehicles had to have such a high fuel pressure.

Looks like they would have been able to make it run on much less pressure, and solved a lot of fuel pump related issues.

Actually fuel pressure is part of fuel mix control.
The VCM computer does not have a fuel pressure senser and do know what the fuel pressure is.
It depends on the right fuel pressure to be there.
If it is not there it can not control the right fuel mixture.
They set the fuel pressure up to a certain pressure give the engine a good fast percise squirt from the injector.
Better fuel mix control.
If you look all newer cars and trucks have gone to a high fuel pressure system.
MT