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Discussion Starter · #1 · (Edited)
Yesterday I went out and when I turned the key my fuel pressure didn't come up. Popped the hatch and tried it a couple more times. The fuel pump wasn't kicking on. Unplugged the main harness and plugged it in again and tried it again and bingo pump kicked on with the key.

Once running all was good. Went for a 30 mile rip and shut it off and it happened again. I followed the wires from the pump as best I could and the go to a cluster with some tiny selenoids and small "electrical" boxes and one of them clicks when I turn the key. I hit reset buttons, checked fuses, unhooked batteries, checked the key switch wires and nothing. Then all of the sudden it works. And worked fine once running again.

I assume there is something that tells the pump when to kick on??? What should I be checking? This is a MPI motor.
 

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Discussion Starter · #2 ·
I have been going out and turning the key on about every hour and the fuel pump kicked on 5 times in a row. Now nothing just a click from this thing. The wires go through a fuse then into this thing and then to the fuel pump.
 

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Discussion Starter · #3 ·
That pic is the relay for the fuel pump. There are two pink wires(one about 10 gauge and one about 18) that are hot no mattter if the key is on or not. Then there is a small green wire and a large grey wire. Neither one of those get hot with or without the key being on. The grey wire goes to the pump. When I jump the large pink to the grey the pump turns on so I know that is all good.

I'm thinking either the relay is bad or the green wire isn't providing voltage when the key is turned on??? I have no idea if it suppose to but I would think there has to be some type of "trigger" wire to get power to the grey wire? But I have no idea what goes on inside these so that is just a guess. Hopefully it's the relay.
 

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I'm wondering if I'm having the same problem you are. When it quits, does it restart briefly then die? Is it idling rough? What motor? I can't even find the pump on mine- it looks like it's under the oil cooler.
 

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The easiest thing to try is replace the fuel pump relay, of course if unplugging and replugging the main harness fixed it before, check your main harness connectors for corrosion.
 

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Discussion Starter · #6 ·
Philcat said:
The easiest thing to try is replace the fuel pump relay, of course if unplugging and replugging the main harness fixed it before, check your main harness connectors for corrosion.
No corrosion anywhere I think it was coincidence. The second time it happened I unplugged the harness, hit reset buttons, unhooked batteries, unplugged relays, etc, etc and nothing. Then it just decided to kick on. The relay does "click" however every time.

A local auto parts store has the relay so I am going to start there.
 

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Discussion Starter · #7 ·
Tommygun said:
I'm wondering if I'm having the same problem you are. When it quits, does it restart briefly then die? Is it idling rough? What motor? I can't even find the pump on mine- it looks like it's under the oil cooler.
No, once my pump kicks on it starts and runs fine. Ran it for about 70 miles that day and never missed a lick. It just doesn't kick the fuel pump on every time like it should.
 

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if you've got one (I'm assuming you do), have you checked the oil pressure switch / cut-out and associated wiring? I recently had one of these go bad andit was giving intermittent fuel pump inoperation as the primary symptom... once I bypassed it and everything worked great (yes I replaced it after!), it was like.. duh...
 

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Discussion Starter · #9 ·
Well I picked up a new relay and it seems to be working. I flipped the key switch about 10 times and the fuel pump kicked on every time. So hopefully that is all it was. I'll keep checking it to make sure. The good news is I figured out how to "hotwire" it just in case it does happen again!
 
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