97 Blazer low fuel pressure new pump stalls in gear

[ChevyFamily]

Just put a new aftermarket pump in my 1997 Chevy Blazer after finding out the previous one was leaking. The pump has been in the car for about a month.*

The other day she wouldn't start (at the Disneyland Parking lot of all places) and it had to be towed home. I can hear the pump when I turn the key. Pressure tested when I got home and found it to be at 50PSI.

When I spray some starter fluid in the intake it will run and idle, but as soon as I put it in gear it will sputter and stall.

Before it stopped starting, the blazer would occasionally sputter while coming to a stop or low idle. Also, the blazer would occasionally idle high around 1500RPM normally when it was cold.

I know this is usually a pump problem and I have changed it on the Blazer 4 times if I am remembering right. I am wondering if there might be something else wrong other then the pump.

I have seen other people mention the fuel pressure regulator. Could this be the cause of my problems? Where is it located? Anyone have a removal guide?

Thanks in advance,
Brandon

[MT-2500]

Aftermarket or Airtex fuel pump is your problem.
Which is it?
Either way.
Drop it in the trash can and get a Dephi oem type pump.

[MT-2500]

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 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.

[ChevyFamily]

MT Thanks for the suggestions. The part is aftermarket from autozone, I forget the brand. I purchased it from them some years back and it has a lifetime warranty so I just swap them out there in the past.

When we changed it a month back we had to change the connection type from a four port in a square config to a straight line. See rockauto part [AIRTEX Part # E3953M] for a pic. I don't know if this is the same brand as mine, but this one is using the same connection change. Does anyone know if Chevy has changed their pump connection. I thought I saw on another forum posting that someone had replaced theirs with an OEM but had to change the cable.

I really don't want to change that pump again. It really is a weekend killer. Plus the tank is 3/4 full :/

[MT-2500]

Run the fuel pressure test.
And if it does not pass the test you need to replace the fuel pump.
Also if you installed a connector /plug in solder the wires instead of the connectors that come with the kit.
And confirm good voltage and ground to fuel pump.

If it is a aftermarket pump or Airtex pump exchange it back in for a Delphi pump and be done with you problems.

Good Luck

[ChevyFamily]

"A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs."

How would I go about doing this?

[MT-2500]

As said block off or plug return line.
Or you can check direct fuel pump pressure on fuel filter in line.