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Jakethewhite

87 gl wagon no power to fuel pump

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I have an 87 gl and recently the fuel pump stopped working so I bought a new fuel pump but this wasn't the problem because it still didn't work. Then I check on here and every one said it is the relay so I have a new relay and still not fixed. Any ideas what could be causing it? Everything else works on the car but there is no power to the fuel pump at all. 

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Encouraging slap on the back:

You can fix it JaketheWhite, just take a more methotical approach. You can do it.

I'm hesitant to mention it because of the obvious risks working with fuel and electricity, so no liability on my part...

 

Get the right tools:

I highly recommend a powerprobe so you quickly test points with both ground and power stupid fast.

Also get enough cable with it so you could potentually test trailer brake lights from the car's battery.

 

Steps:

Test everything individually i.e. 

* test your old fuel pump by itself

* test new pump

* test the ground wire to chassis from the pump

* test the hot wire from the relay to the pump, is it continuous?

* test the relay with a continuitiy light and powerprobe

 

Without a powerprobe:

* Grab the hot wire from your passenger tail light and extend it down to the fuel pump, turn on your lights and try to start it.

* pass/fail you know where to spend your time: fuses, relays, wires, pumps, ignition switch, dead battery, plugged filter, pinched hose, no fuel in tank, bad gas in tank, water in tank, no tank, window tint too dark, unpaid parking tickets, man-made global warming, lieing politicians, that thing you did last summer, you could be on your way to litterally changing the world.

* Replace garage fire damage as required

 

Tips: 

* Presume that you have two (or three) broken pieces instead of one.

* PowerProbe has had several model releases. They are all good. Find a mechanic that often "buys the new one", and buy his old one with a 12 pack of beer.

Edited by jsyme
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That model uses a "rev sensing" relay to control the + 12v to the pump.  It is bolted up above the hood latch pull in the drivers kickpanel area.

 

It only passes power through when it senses a pulse on the Tach wire. (yellow)

 

I would suggest testing for tach pulse at the yellow wire (clip the lead to 12v+ and probe the wire while cranking, should strobe the light)

 

if you have that, and power to the relay, the relay is failed.  If that all passes, you have a break in the wire to pump or it's ground.

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I could not find any relay with a yellow wire above the hood latch but I checked the fuel pump relay again (blue switch next to the ignition relay connected above the ecu) And it has 4 black and white wires. When I turn the key on I have power at The 1 and 2 side. But the 3 and 4 side is the switch side and i only have power on the 4 side not the 3. Even when I turn the key over still no power. Does this mean I need a new relay? Or do I need to find that rev sensor with a yellow wire?

 

 

The only thing above the hood latch is the fuse box and way up above that was 3 relays two had black wires and one had two blue wires and one red wire with a yellow stripe and a green wire with a stripe.

Thanks

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I could not find any relay with a yellow wire above the hood latch but I checked the fuel pump relay again (blue switch next to the ignition relay connected above the ecu) And it has 4 black and white wires. When I turn the key on I have power at The 1 and 2 side. But the 3 and 4 side is the switch side and i only have power on the 4 side not the 3. Even when I turn the key over still no power. Does this mean I need a new relay? Or do I need to find that rev sensor with a yellow wire?

 

 

The only thing above the hood latch is the fuse box and way up above that was 3 relays two had black wires and one had two blue wires and one red wire with a yellow stripe and a green wire with a stripe.

Thanks

 

Ah.....2wd?  or California Car?  Must be cause sounds like you have hte SPFI fuel system which does use a simple relay.  49 state 87's had Carbs and the Rev sensor type relay.

 

You have a simple 4 pole standard hitachi/mitsuba relay.  From what you describe yes it sounds like it failed and isn't closing.  Test pump by bypassing with a jumper from 3 to 4.  

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So bypassed the pole like you said and immediately heard the pump turn on . A great sound to hear after all the digging through all the wires and testing allvthe power points. So next step I would guess is order a new relay?

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I think I might be out of fuel. Got the new relay and inst alled it . By added to see if it was sucking fuel and no fue came out. I had just put about 2 gallon in but maybe that's not enough. Going to add a few more in the morning and see if it helps. And yes it's a California car 4x4

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