Engine stalls while driving?

I see you replaced the pump but you have a return fuel system which means the regulator will route "excess" pressure or fuel back to the tank. We need to check the return system for issues including restrictions. However, I suspect the regulator may be allowing too much fuel or pressure back to the tank which causes your low pressure. The reason is, your running pressure should be a minimum of 30 PSI so it is not that far out but with a new pump you would expect it to be higher so that means one of three things. First it is a weak pump. Second, you have a restriction in the supply line, or there is a "leak" in the system allowing pressure to bleed off to the tank.

Let me know if you have questions and we can go from there. Thanks

Fuel pressure should be 35-45 psi. I would suggest replacing the regulator.

OE instructions below.

Let me know if this helps.

Rich

Good afternoon,

If you only have 28 pounds, it is a fuel pump issue.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the spec for you.

What brand pump did you use?

Roy

the new fuel pump was made by car quest. don't know what brand the new pressure regulator is and the running pressure is 28 psi, no higher.. it wont keep a constant idle. i have to check the rpm with the obd 2 that i bought because truck wasn't made with a rpm meter and which lines on the fuel pump is the return line? thanks in advance..

The large line goes to the fuel rail and the smaller line is the return line form the rail.

When it shuts off, does it start right back up?

https://www.2carpros.com/articles/stall-at-idle

Roy

yes, will usually run for a few minutes then instantly shuts off and cranks back up and run few minutes and shuts off again. wish could talk on phone.. i'm a bad typer.

when i first got it i was told it had a bad EGR valve.. replaced that. IAC valve, MAF, fuel pump, filter, pressure switch. checked inertia switch. checked for vacuum leaks with starter fluid. alternator, battery. bought pressure tester. checked all fuses and relays. and bought a obd2.

no check engine light on.

also cleaned the throttle body and the mass air flow area and filter and put on a new throttle position sensor.

can i test the pressure straight from the pump?

You can but it will read the same as at the rail.

I think your new pump is either wrong or bad.

Roy

Okay, thanks Roy. I'm going to clean the return line first and if that does not help. Off with the pump. thanks

You are welcome.

Always glad to help.

Keep me updated.

Roy

Took it back for another pump and now pressure is lower.

That's idling pressure.

Yep, you need a pump.

Replace it and ask either for an AC delco or delphi pump.

Roy

This is the second new one I put on..first was a Carquest. this one is a Airtex. how long should line hold pressure? Mine loses pressure within seconds of it shutting off.

It should only drop about 3-5 pounds.

There is a check valve in the pump that keeps residual pressure. If that is not holding, it will bleed down.

When you drop the tank. look inside for any debris or dirt in the tank.

Roy

i have the bed off of my truck and the inside of the tank is clean.

Okay, check the pressure when you install the pump.

Roy

Old wasn't working. second one ran at 28. third one runs at about 27.

Okay, get a pair of vice grips and clamp off the line at the fuel rail and see what the pressure reads. The return line.

Roy

Since I changed the fuel pump this second time, it's shutting off faster.

Okay, did you clamp off the line as I suggested?

Roy

Yes, the pressure didn't go up.

The one coming out of the pressure regulator.

Okay, so it is not the regulator but by doing that, it should have dead headed the pressure which means the pressure should have gone way up.

Are the plugs contaminated with fuel?

Roy

They haven't been.

Just out of curiosity, check the voltage to the pump when it is running.

Roy

Can't right now headed to work. wont be able to until 5:00 pm central standard time. but will check.

No problem. I will be on all day and to about 9:00 PM tonight EST.

Roy

Hey, Roy. When I get home, which wires do I need to connect to and what exact setting for my multi-meter?

Set the meter to DC volts. You should see battery voltage for 2 seconds with the key on.

The pink/black wire is what you test.

Roy

Okay Roy, goes up to a little over 12 then drops to a little over 6.

12.05 down to 6.71.

Is that cranking or with the key on? Remember what I told you that the pump will only have power for 2 seconds with the key on.

It will go to full voltage with it cranking

Roy

Just turning the key on.

Hey Roy, taking the new fuel pump off and taking back to the store, said it would take a few days to come in. hope it fixed the problem. ordered Delphi.

Okay, but I would still like you to test the voltage cranking when you put the new pump in.

It is hard to check the voltage at 2 seconds.

Roy

Okay, that was originally why I videoed it. to see the ups and downs progression within that time frame. I will hit you back up when i get the other one in. probably Friday or Saturday. have a good one and appreciate your help.