fuel pressure question

6 months ago i replaced my fuel pump with an airtex pump. 6 months later (2 weeks ago) the truck stopped starting. I bought a pressure meter and sure enough it was too ow to start the truck (45ish psi). I got another airtex pump as a warrenty replacement and had it installed. Just for kicks I hooked the pressure meter back up and tested the pressure.

Now here is the real question:
When i turn the key to run i get 60-61 psi, after the pump stops running my pressure drops off sharply. Is this normal? If not normal, what is normal?

1997 Chevy Blazer 4x4 4-door 4.3l Vortec with 110000 miles.

Pressure is low.
But with a Airtex pump you are luckie to have any pressure.
Key on you should have 65 lbs with no fast leak downs.
Fast leak down can be fuel pressure regulator leaking or fuel pump check valve not holding or a leaking line.

Hook you gauge direct on to the inline at fuel filter.
Check for full pressure of 95-105 lbs and no fast leak down there.
Just do not run pump at full pressure over a few seconds.
Just long enought for test.

Here is guide lines for feul pump and pressure test.

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 over 75-85 lbs.

Specs is 95-100 full pressure on yours and running pressure is 60/66 at fuel rail.
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 over 75-85 or more and up to 95-105.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

That is normal. However, You should consider in using a Delco fuel pump for you replacement. Airtex has been noted to have a high return rate. There cost is higher, but you have pease of mind of not breaking down. I replaced in 3 of my blazers 94, 96, & 97. with Delco and never had to go back in the tank because of failures. Al 3 of them were done about 1 to 1 1/2 years ago. Good Luck.

I agree Airtex pumps are crap.

Having said that, I didn't know the first time it went out, and the second one was a freebie warrenty replacement. I think i quoted the ACdelco part at $450 or so, and i got this one for $115. Sometimes you have to get the cheap part if its all you can afford.


P.S.
How do I block off the return line to check the pump? How do I connect it to the fuel filter? My gauge has a schrader valve fitting, my filter has that GM adapter thing on it.

Plug it is best.
If there is a rubber part on line you can pinck the rubber part.
Always check pressure cold and hot.
Most parts places have adapter fitting fo checking pressure at fuel filter line.
Good Luck

Was that 115 the complete fuel pump module or other?
Complete Ac delco pump modules are usually about 25 dollars over complete Airtex pump modules.
Most parts places will adjust a airtex fuel pump on to a Good ac delco pump on the warranty replacement.
Carquest has dumped airtex pumps like a hot spud and went to all all Ac delco pumps.

I called the local GM dealership and the price was around $450, maybe 430 not 100% sure. I found the airtex online for $115. If it will last 6 months I will be in a better place financially and will get the propper part at that time. If you know of a place that will sell it for $200 bucks or so by all means let me know. I keep a seperate bank account to buy things off the internet so I will buy it from whomever. The part number is MU112

How hard is is to change the pressure regulator? If its not that bad i might just replace it anyway.

Proper testing before throwing parts at it.
Go threw the fuel pressure test as outlined in upper post.

Check your local parts places for prices and brands of fuel pumps.
Only use a ac delco/delphi pump unless you want to keep replacing it.