where does this wire go?? fuel pump not working - The 1947 - Present Chevrolet & GMC Truck Message Board Network

texasfunk · 04-29-2010, 10:43 PM

ok, so i went to start my 87, ran for a while, then nothing, i spent all day hunting down a parasitic draw and a short that was burning out my horn, after doing the test light thing and pulling the fuses i found the prob, now, the fuel pump wont turn on, could it have been something while pulling all the fuses? it also doesnt have a tank selector switch (hasnt for a while) and would this affect it after pulling everything? there is also a wire hanging off the fuel pump relay which i dont beleive has ever been hooked up, but with all the wire jumbling it very well could have been, i run it to hot and the pump turns on so the pump is good, any other ideas guys? im losing it on this one

texasfunk · 04-29-2010, 10:46 PM

and im sure it matters but i am no longer running tbi, it is a carb'd 355 and it doesnt have a mech pump

JR0187 · 04-29-2010, 10:59 PM

Does the relay kick on when you turn the switch on?

*78 Chevyrado* · 04-29-2010, 11:04 PM

Not sure what it's for, but my 87 had the same wire, unhooked. when I checked the terminal with your same question, it looked like there had never been anything connected. It ran perfectly fine without it. It's likely an extra wire for some option your truck doesnt have, or it may be for troubleshooting.

texasfunk · 04-29-2010, 11:06 PM

Quote:

Originally Posted by JR0187

Does the relay kick on when you turn the switch on?

no, it doesnt..and chevyrado, i figured thats what it was, cause as long as i have known it was unhooked, but when i ran it to hot it pumped fuel so it got me thinking...

BIG V · 04-30-2010, 02:24 AM

that wire to the best of my knowledge is to test the relay. it connects to a hot lead to see if the relay or pump is bad... with out power no fuel pump working could be the relay or the pump add power to the wire if fuel pump starts working the relay is bad and the pump is good, add power and its still not pumping fuel pump bad..

**Desert1957** · 05-03-2010, 07:32 PM

Here is a link to this question a while back , Hope this helps....

Desert

http://67-72chevytrucks.com/vboard/s...d.php?t=355256

87chevy.com · 05-04-2010, 09:12 PM

you will need a schematic. The wire hangin off is to test the pump.. maybe even the relay depending on what terminal its connected to. Remove the relay and take a look at it, see if it has a diagram on it. Usually it should, Theres 2 wires for the control side (power and ground) in order for the relay to do work. then theres the power and output. when the relays got both power and ground, and if its a good relay, the internals will click over and will connect a power wire (mentioned above) and the output together. That being said you can test that relay. A 9v battery will click the relay over once you determine the terminals to check. You know your pumps good since you manually tested it. Your problem lies between the ignition switch and relay. This is where the diagram come in handy. Without that... good luck... post up your findings
clint

04-29-2010, 10:43 PM	#1
texasfunk Registered User Join Date: Jun 2009 Location: Lubbock, TX Posts: 1,671	where does this wire go?? fuel pump not working ok, so i went to start my 87, ran for a while, then nothing, i spent all day hunting down a parasitic draw and a short that was burning out my horn, after doing the test light thing and pulling the fuses i found the prob, now, the fuel pump wont turn on, could it have been something while pulling all the fuses? it also doesnt have a tank selector switch (hasnt for a while) and would this affect it after pulling everything? there is also a wire hanging off the fuel pump relay which i dont beleive has ever been hooked up, but with all the wire jumbling it very well could have been, i run it to hot and the pump turns on so the pump is good, any other ideas guys? im losing it on this one Attached Images __________________ 2006 GMC Sierra CCSB, 6.0 swap 2000 Chevy C3500 Crew Cab shortbed dually 1999 Chevy c2500 Crew Cab shortbed 1982 El Camino 350/350 1979 K5 2wd blazer bagged/bodied 1986 Monte Carlo SS 1991 Chevy CK SWB-67 clip and tailgate, bagged 350/700r4 1955 Chevy Bel Air 2014 Chevy Silverado ccsb Last edited by texasfunk; 04-29-2010 at 10:45 PM.

04-29-2010, 10:46 PM	#2
texasfunk Registered User Join Date: Jun 2009 Location: Lubbock, TX Posts: 1,671	Re: where does this wire go?? fuel pump not working and im sure it matters but i am no longer running tbi, it is a carb'd 355 and it doesnt have a mech pump __________________ 2006 GMC Sierra CCSB, 6.0 swap 2000 Chevy C3500 Crew Cab shortbed dually 1999 Chevy c2500 Crew Cab shortbed 1982 El Camino 350/350 1979 K5 2wd blazer bagged/bodied 1986 Monte Carlo SS 1991 Chevy CK SWB-67 clip and tailgate, bagged 350/700r4 1955 Chevy Bel Air 2014 Chevy Silverado ccsb

04-29-2010, 10:59 PM	#3
JR0187 Registered User Join Date: Mar 2010 Location: Piedmont, AL Posts: 49	Re: where does this wire go?? fuel pump not working Does the relay kick on when you turn the switch on?

04-29-2010, 11:04 PM	#4
78 Chevyrado Account Suspended Join Date: Dec 2007 Location: Unnapreciative, Trollville Posts: 2,079	Re: where does this wire go?? fuel pump not working Not sure what it's for, but my 87 had the same wire, unhooked. when I checked the terminal with your same question, it looked like there had never been anything connected. It ran perfectly fine without it. It's likely an extra wire for some option your truck doesnt have, or it may be for troubleshooting.

04-30-2010, 02:24 AM	#6
BIG V Registered User Join Date: Jul 2009 Location: Northern California Posts: 411	Re: where does this wire go?? fuel pump not working that wire to the best of my knowledge is to test the relay. it connects to a hot lead to see if the relay or pump is bad... with out power no fuel pump working could be the relay or the pump add power to the wire if fuel pump starts working the relay is bad and the pump is good, add power and its still not pumping fuel pump bad..

05-03-2010, 07:32 PM	#7
Desert1957 Registered User Join Date: Apr 2009 Location: New Freedom Pa. Posts: 1,335	Re: where does this wire go?? fuel pump not working Here is a link to this question a while back , Hope this helps.... Desert http://67-72chevytrucks.com/vboard/s...d.php?t=355256

05-04-2010, 09:12 PM	#8
87chevy.com BMW & ASE Master Certified Join Date: Feb 2004 Location: Houston, Texas Posts: 1,256	Re: where does this wire go?? fuel pump not working you will need a schematic. The wire hangin off is to test the pump.. maybe even the relay depending on what terminal its connected to. Remove the relay and take a look at it, see if it has a diagram on it. Usually it should, Theres 2 wires for the control side (power and ground) in order for the relay to do work. then theres the power and output. when the relays got both power and ground, and if its a good relay, the internals will click over and will connect a power wire (mentioned above) and the output together. That being said you can test that relay. A 9v battery will click the relay over once you determine the terminals to check. You know your pumps good since you manually tested it. Your problem lies between the ignition switch and relay. This is where the diagram come in handy. Without that... good luck... post up your findings clint __________________ 1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress



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