Fuel Pump

Tiny
JIMDANT
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • MANUAL
  • 250,000 MILES
It quit running, I couldn't hear the fuel pump running so I so I checked the fuel pressure. It was zero. I checked the relay which was good, I pulled the old pump and checked it. It proved to be bad. I put a new pump in it, but still no fuel pressure. I jumped the fuse/relay box wire going to the fuel pump and the pump ran. I cant get a signal from the ecu to the relay telling it to send power to the pump. I put a second ecu in but still no signal to the relay, so I put the original ecu back in it. And, I can see this problem has apparently happened before. Someone skinned back some of the insulation on the wires that send power through the relay to the pump. I thought maybe it is a theft deterrence issue so I disconnected the battery cables and held them together for a little over one minute. Still nothing. Tried to read the error codes, but the reader kept getting link errors.

I have no idea where to go from here. Please. HELP!
Do you
have the same problem?
Yes
No
Tuesday, February 2nd, 2016 AT 11:11 AM

5 Replies

Tiny
HMAC300
  • EXPERT
Theft isn't fixed like you did it either has a diode in key or like what i'm sending. Try tweeking prongs on relay a tad so they get better contact. Also if new fuel pump was installed it should have come with about a foot of harness to install with it as connector has changed as the others were no good.
Was this
answer
helpful?
Yes
No
Tuesday, February 2nd, 2016 AT 12:07 PM
Tiny
JIMDANT
  • MEMBER
Thanks for the reply and for the attachment. The key doesn't have a diode so maybe it doesn't even have theft deterrent.
I did get a new plug with the new pump, but the old plug looks just like the new one. The wires are in the same location. The colors are the same. So, I went to the relay and what I realized is that the wires going out the bottom of the relay box are different colors than at the wires at the pump. Apparently the pump has already been replaced and the harness already have the new plug on it. It's getting late here, but tomorrow I'm going to get under it and check the connections for the replacement plug. It's been my experience that many people make very poor connections that don't hold up over time. Here's hoping that's the problem!
Was this
answer
helpful?
Yes
No
Tuesday, February 2nd, 2016 AT 2:17 PM
Tiny
HMAC300
  • EXPERT
All late model cars have anti theft
Was this
answer
helpful?
Yes
No
Tuesday, February 2nd, 2016 AT 3:37 PM
Tiny
JIMDANT
  • MEMBER
I replaced the plug with the new one but still the pump doesn't turn on when I turn on the ignition. Is there any way to check the theft deterrent system? I don't believe I'm getting a signal out of the ecu to the relay.
Was this
answer
helpful?
Yes
No
Wednesday, February 3rd, 2016 AT 12:34 PM
Tiny
HMAC300
  • EXPERT
Yes I sent that in very first reply.
Was this
answer
helpful?
Yes
No
Wednesday, February 3rd, 2016 AT 12:43 PM

Please login or register to post a reply.

Recommended Guides