dmpi1719

I have a 2000 Chevy Van 1500, 5.7L V8. The fuel pump went out about 8 weeks ago. I confirmed the relay was working and got a fuel pressure gauge and there was zero pressure when I turned the key on and couldn't hear the pump. After I replaced the pump (I bought a Bosch replacement pump), the van fired right up and everything was fine. My wife took the van on a trip to upper New York State about three weeks ago (1250 miles round trip). On the way home she got 20 miles from home and the van died. She said it just shut off. She tried to restart but nothing happened, it didn't even turn over. She then called me. Before I could get out of my neighborhood, she called back and said the van had started back up. She drove it home and there were no further problems.


I tried for several days to get it to stop again but it wouldn't. It always started right up and ran normally. No hesitation, no stuttering, good power. Then, last week I took it out to the store. I parked it and went inside and when I came out about an hour later the van would not start. It cranks normally but no start. I checked the spark (it's good) and I got someone to turn the key on while I checked the fuel pump relay and it was fine but I couldn't hear the pump come on.


I immediately thought it was the new pump. Got it towed home and checked the pressure; zero again. I replaced it and now this pump will not come on either. I jumped the pump that I removed and it ran normally. Now I know there's no power to the pump.


What might cause a lack of power to the pump? I've followed the wires and checked the connections. They all look good. I don't think it's the ECU because the relay is working. I'm stumped on this one and would appreciate your advice/help.

canucklehead

If it would not even turn over, and now does but no power to pump it has to be electrical. Maybe a bad ground, or issue with the ignition switch. Might be unrelated to pump, or the issue in the first place.

dmpi1719

Canucklehead,


I think you're right but I don't know where else to look. I've tried the relay and it's good. I tried checking the power at the pump. The pigtail that connects to the pump has a good ground but the power line is dead. I don't know where to look now. Has anybody else had a problem like this?

canucklehead

The starter relay is the same relay part number. You could swap them just for a test.
Also, you could test the continuity of that power wire and the pin for it at the relay outlet with a ohm meter. I haven't got a wiring diagram to see if there is anything else between the relay and the pump. I don't think so though.
Have you check the body fuse. Is there power at the relay?

dmpi1719

I did switch it out with the starter relay. That's how I confirmed it was good. There is definitely power at the relay. Using a test light I verified power at startup and good ground. The relay has 4 pins. The control pins are 85 and 86. Using a test light I confirmed that 86 is the ground. I connected the test light to pin 85 and when I turned the key to on it lighted.

The power side is 30 and 87. I also checked pin 87 and discovered it is always hot. I then tried jumping 30 and 87 to see if the pump came on but it did not. The jump wire (paper clip) got hot but no power to the pump.

canucklehead

If the paper clip got hot, is the new pump seized? Have you put power direct at the pump to see if it runs?

dmpi1719

I'll give that a try this evening when I get off work. I don't have a wiring diagram but the pigtail wires are purple, gray, black and black-with white stripe. I think gray and black are power and ground. Any thoughts?

Meanwhile, I found a good tutorial about how to check relays at this link: http://www.autoshop101.com/forms/hweb2.pdf

I'm going to re-check the relay. I've checked the control side and it's good. I'll use a test light to see if it could possibly be burned on the load side.

Also, do you know if there is an in-line fuse on the 2000 Express Van?

canucklehead

You may also try the rubber mallet to the underside of the gas tank while someone cranks it. If the new pump is stuck that will jar it loose, but it also means you got a bad pump....

americosupply

dmpi1719 did you find the problem.
I have an o2 silverado same thing. It died on me on the way home at a light , got to fire up ran ok for two more blocks the died at the light. Installed the new pump and filter now I have no fuel pressure at all. I even cracked it without a filter on and nothing. The pump does not even come on at all. I too verified the relay is good and checked all fuses under the hood. I feel like I missed something.