help fuel pump relay need to get to work in the morning!!!!!

86gtriceeater · May 11, 2008

i was drivig yesterday and my fuel pump just went up stopped turned key forward no fuel pump...towed it home and tested with new relay no go...started testing voltage and i get 12v to the yellow wire on the fuel pump relay but nowhere else also the relay under the dash by the fuse panel wont actuate and gets no power...the nut on the stud holding my fusible links on was loose from vibration i guess cause theyre all new and it was tight but anyway i pulled all the fuses none look bad although i know you cant always tell by looking...which fuse is the fuel pump circuit and which fusible link there are like four or five....i'm sure its just a link or fuse itself cause the pumps brand new the the relay turns it on and the eec relay gets power and works so the ground is there WHAT DO I DOOOOO??????????/
TESTED ALL FUSE LINKS AND GET 12V WITH KEY ON

88mouse · May 11, 2008

How old it the pump?

Are you geting power to the pump?

HISSIN50 · May 11, 2008

This is on an '86? If so:

The yellow wire is the feed from the solenoid. If you have 12 volts in said wire, the link should be fine. You should see 12 volts at this wire at all times (I think you had another thread asking about how many terminals show power and when).

What you are probably missing is energization of the relay's coil.
At the red/blk wire, you should see 12 volts any time the key is on. If you dont have it, check for 12 volts going into the inertia switch.

You should have continuity to ground in the tan/lt grn wire when you first turn the key to run (during the prime-out). If you have 12 volts at the red/blk wire, ground at the tan/lt green wire, and the yellow wire shows 12 volts, the last wire (pink/blk) should have 12 volts. This last wire is the feed to the pump. If you have all that and the pump still wont run, check for power and ground at the fuel pump connector (above the tank).

Check the middle-left side of the following diagram:

Courtesy of S&2B's (site host) and Tom Moss (author).

86gtriceeater · May 11, 2008

i have nothing at the inertia switch and only have 12v at the yellow wire and get nothing to the relay under the dash could it be a fuse are they all on the same circuit...it was all working fine then out of no where something snapped....fuel pump is brand new been run fifteen times maybe but thats not it its not getting power to it or the relay...so it goes eec relay (which is working) to the inertia switch then the fp relay then to the pump right? so it's not a fuse link ANYONE KNOW WHICH FUSE THIS CIRCUIT RUNS ON AN 86 GT 5.0? THANKS IN ADVANCE YOU GUYS ROCK

HISSIN50 · May 11, 2008

What is the relay under the dash you speak of?

As for the elusive fuse you ask about, look at the diagram. You have a fusible link on the load side, and you have said that it appears to be fine based on your observations of the yellow wire.

You need to find why you have output at the EEC relay (to be sure, it is the red wire at the EEC relay that matters. If you have power at any other wire at that relay, that doesnt mean the EEC relay is functional) but no VPWR reaching the FP relay's coil.

86gtriceeater · May 11, 2008

okay i'll go check the red wire on the eec relay quick and get back to you the other relay is under the dash drivers side right next to the fuse panel i think its the cruise control relay maybe not sure i dont even have cruise just need to get power to the pump to drive to work in the morning thanks man get right back to ya...you should get paid for advice its saved me so many times

86gtriceeater · May 11, 2008

red wire for sure has 12.5 volts and so does the black and orange wire on the eec power relay what next?

86gtriceeater · May 11, 2008

i just ran a wire from the starter positive side to the pink black wire on the fp relay and the pump turned on so i know the pump is good but the relay isnt getting power

Saleen0679 · May 12, 2008

If you have voltage on the red wire from the EEC relay you should have voltage at one side of the inertia switch. Make sure the inertia switch has been reset and check the R/BK wire on the other side of the inertia switch for voltage.

86gtriceeater · May 12, 2008

okay i went back out and tested and now find i have 12v on the red wire the red/black must be ground obviously because theres no voltage there...thanks for the input i also made sure the inertia switch is okay and its never been tripped as far as i know...i didnt hit anything my fusible links were loose and it just died WHATS NEXT i have to have it running by morning!!!

HISSIN50 · May 12, 2008

86gtriceeater said:
okay i went back out and tested and now find i have 12v on the red wire the red/black must be ground obviously because theres no voltage there...thanks for the input i also made sure the inertia switch is okay and its never been tripped as far as i know...i didnt hit anything my fusible links were loose and it just died WHATS NEXT i have to have it running by morning!!!

Just because a wire does not show a voltage reading on your meter doesnt mean it's grounded.

Saleen0679 is exactly right about needing to find out if you have I/O voltage at the inertia switch. How did you ascertain that the switch is ok? You can't tell visually. There's a decent chance the switch popped or is bad.

1991vert · May 12, 2008

while we're on the topic, which color wire causes the fuel pump to prime?

86gtriceeater · May 12, 2008

so i may have popped the inertia switch altogether? cant i just run a wire from the eec relay that supplies power to the energize the fp relay if so or even not what color wires are those? how do i find i/o voltage what do you mean by that? i'll go grab a good inertia switch and swap it and see if thats the issue..

HISSIN50 · May 12, 2008

86gtriceeater said:
so i may have popped the inertia switch altogether? cant i just run a wire from the eec relay that supplies power to the energize the fp relay if so or even not what color wires are those? how do i find i/o voltage what do you mean by that? i'll go grab a good inertia switch and swap it and see if thats the issue..

Please take no offense here but in the time spent chasing one's tail, the issue could have long since been found and solved without any parts swapping. You can spend 10 seconds testing part of a circuit with your meter and then you know it's good and can forget about it. You keep asking about the same items, which makes one wonder if the things were tested before, and some of the answers to the new questions are actually answered in older posts on this thread.

Are you comfortable reading schematics? If not, we can help. I think this is an issue here. Many questions you ask are answered in the above-diagram.

You do not want to connect VPWR to the FP itself. VPWR is used to control relays and sensors/solenoids, not provide load-power to larger devices like a fuel pump.

I/O = In/Out voltage. It just means checking voltage going into and out of a device.

To answer your previous post, the modulated side of the FP relay coil is the tan/lt green wire. Re-stated, you need 12 volts and ground to the coil terminals of the relay.

Good luck.

86gtriceeater · May 12, 2008

she runs again but still have a question

hissin i dont take offense to that i swapped out the inertia switch which didnt help and thats always been my way of figuring stuff out which is probably why it takes you guys to help i can read the diagrams i do sometimes have trouble expecially when it comes to "custom" wiring like my mass air conversion...i'll try to make a long story short...i tried using a engine harness from a 91 a few years back and to get the fuel pump to prime i had to tap into my stock harness on the DRIVERS side kick panel...yellow...red and the tan/light green that part of it my old friend who just had to help did without soldering only heat shrink and he was also posting questions on here to try to help me...anyway the problem was the tan/lt green wire that he screwed up i must have stepped on it under the carpet and separated the wires enough the pump wouldnt prime anymore...but i STILL HAVE A PROBLEM theres still that relay under the drivers side dash hanging that doesnt do anything any clue as to what it is cruise control relay? my car doesnt have cruise but its part of the stock harness...j

Saleen0679 · May 13, 2008

Supply some of the following if you could:

Pics
Relay part number
Quantity and colors of wiring.
Connector color even helps

86gtriceeater · May 13, 2008

grey connector
part number is quite faded but this is what i could make out
5vb43a025 a?6gc
1 orange/blk strp
2 lt brown/orange stripe (going to the same connection point on the relay)
1 lt blue/black stripe
1 solid black wire

any guesses guys?

Saleen0679 · May 13, 2008

An '86 diagram I have shows the fog lamp relay with those color wires.

86gtriceeater · May 13, 2008

thanks that must be it and my fog lights are off the car anyway thanks alot

help fuel pump relay need to get to work in the morning!!!!!

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