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ZZDaryl, Chevy Technician
Category: Chevy
Satisfied Customers: 12547
Experience:  28 year experience, Master Mechanic
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Put a new fuel pump in and I'm only reading 30psi, It's new

Customer Question

Put a new fuel pump in and I'm only reading 30psi
JA: Have you ever replaced the fuel pump, or is this the original?
Customer: It's new fuel pump. Just installed
JA: What is the model/year of your Chevy?
Customer: 1999 Chevy express 1500 5.0L
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I already said
JA: Sorry about that. I must have missed it. Could you tell me again?
Customer: New fuel pump has been installed. New relay
JA: Anything else you think the mechanic should know?
Customer: It started up a couple times just fine. Then it wouldn't want to start. I used some starting fluid and it started up but not easy. Now it won't start at all.
Submitted: 3 months ago.
Category: Chevy
Expert:  ZZDaryl replied 3 months ago.

Can you tell me how you are checking the fuel pressure?

Customer: replied 3 months ago.
With a fuel pressure test gauge hooked up to the valve. Turn the key to the one position. The fuel pump runs and the gauge reads 30psi. Try to start. Holds steady. It will hold that pressure for 10 minutes. Take it a long time to bleed off the pressure.
Customer: replied 3 months ago.
Let me start from the very beginning. I have a 1999 Chevy Express 1500 with the 5.0L. I bought the van 5 weeks ago in Salt Lake City, Utah. 3 weeks ago I drove it 1400 miles without any issues. About 10 days ago I got a weird sputter and lack of power that lasted for about 20seconds maybe. I figured it was because I was running close to empty. I was trying to get the level down pretty low so I could drop the take and put a new oring gasket at the top of the tank. I noticed I had some fuel running out if I filled it all the way up. Figured it was from there. So I put 10 gallons in at the gas station and go on my way. The next morning, it sputters again. So I pulled the fuel filter on the hunch that maybe I had some bad stuff in there from running it low. I blew out the filter and some pretty nasty dark stuff came out. I flushed the filter with some fresh gas and put it back in. Van started up, I went on my way. Didnt ever sputter again until about 5 days later I shut if off at the gas pump. Put $20 bucks in, went to start it up and it started, then died. And would just crank but not run. I cranked it twice for about 5-10 seconds. Nothing. Waited a minute then it fired up. Went on my way. Restarted it a few times that day without issue. The next morning, I drive it to the store, no issue. But when I come out and try to take off it starts, instantly dies and won't restart. I can't hear the pump running. So I decide that I'm need to replace the pump. I drop the tank there in the lot. Do the job. It fires up, quicker then ever before. I think, sweet. Good to go! Then like 2 days later it starts to die again. But after running for 20 seconds. It did that twice. Then just wouldn't restart. I figure that the new replacement pump was just defective or something, so I drop the tank again, take the part back and throw another new one in. But I had my doubts that that was really the issue so I replaced the fuel pump relay also just for peace of mind. Get the new new pump in and it starts back up. I shut it off. It's hard to start but starts the second time. So now I'm starting to think, it wasn't the fuel pump. It wasn't the relay, maybe it's bad fuel or something. So I drive to shell and put 10 gallons for super unleaded in and some Lucas fuel injector cleaner in it. And take it out in the highway for like 100 miles. Now this morning. It was hard to start the first couple times, but now nothing. I was reading some forums and people were talking about the fuel pressure regulator. So I went and got the tester gauge and checked that. Only getting 30psi, but it hold steady. So that rules of the regulator right? What else could it be? What about a fuel pump ground? One time I put a fuel pump in a 99 Silverado and it had a ground wire from the tank to the frame and I forgot to hook it up and it wouldn't start. Then I saw I had left that off and then it fired right up.
Expert:  ZZDaryl replied 3 months ago.

Did you ever replace the filter after you had more problems?

Customer: replied 3 months ago.
When I put the second new pump in. Why do you think I new fuel pump would only be putting out 30psi?
Expert:  ZZDaryl replied 3 months ago.

The regulator is made to create a restriction so the problem could be the regulator, this is assuming there is not a leak someplace else, like a injector. I would start by finding a place to pinch off the return and see if the pressure goes up to normal or higher, if it does not I would check the oil to be sure there is not a bunch of fuel in the oil, that would indicate a leak into the engine. If the pressure does not go up and there is not a lot of fuel in the oil, I would start by checking the voltage to the fuel pump, if that is good I would check the ground to be sure it is good.

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