In need of some wisdom...

87 flatbed · 07-08-2007, 08:18 PM

I have an 87 1-ton silverado; 7.4l TBI... My problem: I'm not getting any fuel from either tank, no whine sound, no nothing. Could someone walk me through the steps to troubleshoot this dilema? Thank you much... 87 flatbed.

75K30 · 07-08-2007, 09:18 PM

Alright 87 flatbed:
I believe you will get some action here. Since it sounds like you have dual tanks, and neither of the pumps are running, you might have a voltage supplu problem. May check the switch that selects the tanks for input and output voltages, as well as the relays.
Not likely that both pumps failed at the same time, so it is reasonable to assume that they are not getting told to turn on.
For electrical troubleshooting, you can go to www.autozone.com and download the electrical schematics. If you have difficulties reading a schematic, let us know, and someone can help you read them. You will need something to verify voltage like a test light, but a meter would be a much better tool.
You should get some additional ideas from others willing to help soon.

scottie · 07-09-2007, 07:46 PM

check the fuse for the fuel pump........... 99 out of 100 times thats what this is caused by

ddraszt · 07-09-2007, 08:40 PM

neither pump is functioning? How about the fuel pump relay... often they are the problem. In fact a lot of time (not always)the schematic for them is stamped on the relay so you can test for supply and output voltage from it. I know on my 88 and years after it was right on the firewall behind a black plastic cover. Just something to check.

07-08-2007, 08:18 PM	#1
87 flatbed Junior Member Join Date: Jul 2007 Posts: 3	In need of some wisdom... I have an 87 1-ton silverado; 7.4l TBI... My problem: I'm not getting any fuel from either tank, no whine sound, no nothing. Could someone walk me through the steps to troubleshoot this dilema? Thank you much... 87 flatbed.

07-09-2007, 07:46 PM	#3
scottie Senior Member Join Date: Jan 2006 Location: South Florida (Palm Beach), originally from south of BOSTON Posts: 644	check the fuse for the fuel pump........... 99 out of 100 times thats what this is caused by __________________ im a straight shooter with upper management written all over me

07-09-2007, 08:40 PM	#4
ddraszt Full Member Join Date: Jun 2007 Location: arlington wa Posts: 43	neither pump is functioning? How about the fuel pump relay... often they are the problem. In fact a lot of time (not always)the schematic for them is stamped on the relay so you can test for supply and output voltage from it. I know on my 88 and years after it was right on the firewall behind a black plastic cover. Just something to check. __________________ "It is what it is"

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07-08-2007, 09:18 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,636	Alright 87 flatbed: I believe you will get some action here. Since it sounds like you have dual tanks, and neither of the pumps are running, you might have a voltage supplu problem. May check the switch that selects the tanks for input and output voltages, as well as the relays. Not likely that both pumps failed at the same time, so it is reasonable to assume that they are not getting told to turn on. For electrical troubleshooting, you can go to www.autozone.com and download the electrical schematics. If you have difficulties reading a schematic, let us know, and someone can help you read them. You will need something to verify voltage like a test light, but a meter would be a much better tool. You should get some additional ideas from others willing to help soon.