My '95 Blazer stalls periodically when pressing the gas from a stop (stop light or after starting). It usually runs for maybe 30 minutes and then stall at a stop light when I lightly accelerate from the stop. Sometimes it won't stall on a short trip. It's fairly intermittent.
After it stalls it will never immediately restart. I have to wait ~10 minutes and then it starts every time. It runs great other than the stalling.
I also have an EGR code being thrown so I cleaned it and replaced the seal. The code is still being thrown.
At this point I started looking at the fuel system.

Hooked up a pressure gauge:
turned the key to ACC: ~60psi
Start the engine: 60psi but then goes down to about 54psi
Stop the engine and wait 5 min: ~52 psi

At this point I assume the Fuel regulator is good.

I left the fuel pressure gauge hooked up and went for a drive. It stalled in a parking lot. The pressure was around 40psi. I then relieved the pressure to zero psi.
With the key to ACC: zero psi
cranked the engine: still zero psi.
Waited ~10 minutes and put the key to ACC: ~60psi (then and cranked and started the engine -- it ran fine)

Can we say with almost certainty that the fuel pump is at fault and needs to be replaced?

 

I just found out it had the fuel pump and filter replaced in 2009. Not very much usage on the truck since then.

So I'm now thinking ICM or fuel pump relay??

Any suggestions?

 

I paid to have a fuel pump replaced twice before I dropped the tank myself and found the wires burnt that attach to it. I replaced and soldered on new wires and new pump and has run good ever since. That 3rd time seems to be the charm so far...

 

The fuel relay is good (it supplies power to the pump but the pump does not engage).
Since the pump is being powered but does not turn on it has to be a faulty fuel pump correct?

 

your pump might be going i do suggest putting a good pump in her ac delco or delphi if you do change the pump

also change the fuel filter if you replace the pump

 

Thanks for the suggestion for Delphi or AC Delco. That is the one thing that is repeated (only use Delphi or AC Delco on pump replacement).

So, the excess fuel is super-heated (somehow?) and then returned back into the fuel tank and that eventually shuts down the pump? The reason for this a low-quality or failing pump?
Does that make sense to anyone?

 

you did the leak down test so i do agree that the pump is weak when the truck dont start do you get any pressure at all ?

 

Actually, no. It was an attempt on a new fuel system design that works fine till something goes wrong. Higher pressure at a spray nozzle = better atomization, thus fuel burn efficiency, right?
But..
A pump basically designed to move n liters at 40 lbs pressure for 100,000 miles doesnt last very long moving same amount at 60 lbs pressure.
GM OE equipment engineers understood the design needs.
But you buy into the vehicle, you buy into it. Just part of the package.

Someday Edelbrock may build a manifold that will allow Bosch standard injectors on a 40 lb rail but somehow I have the feeling that day may have already gone by.

 

When it stalls and does not start the pressure will read ~40 psi but then I bleed the pressure down to zero and try to start the engine -- the pressure stays at zero psi (and I can't hear the fuel pump running).

So the plan is to replace the following from rockauto:
-Fuel pump (with AC Delco EP381 -- wholesaler closeout price of $40.79) --Can I use this with the Spectra hanger that is on the truck??
-Fuel pump screen (ACDELCO Part # TS7) (? -- there was actually two screens listed but this one is less expensive ($6.45))
-Do I need to replace the two year old Spectra fuel hanger assembly that is currently in the truck?
-fuel tank attaching hardware? More Information for DORMAN 55157
-the straps look ok so I'm not going to order them.

Question: is the 'hanger assembly' and the 'fuel tank sending unit' one in the same?

If I need to replace the hanger assembly I'll then go with all Delphi:
DELPHI Part # FL0255 (FUEL PUMP HANGER ASSEMBLY)
DELPHI Part # FE0114 (FUEL PUMP)
DELPHI Part # FS0034 (FUEL PUMP STRAINER)

Thanks for all the help!

 

Just to update things. I replaced the pump (filter and sender also) and it works perfectly even with the outside temp at 95F. I've driven it everywhere and can't get it to stall.
Thanks for the help.