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Fuel pump no power to plug

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Old Oct 12, 2019 | 07:12 PM
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From: Iowa
Fuel pump no power to plug

I will do my best to explain my situation. I am trying to get a 93 fd started that has been sitting a while. I pulled the fuel pump and it was rusted up pretty bad. I cleaned it up and put a new pump in. I put power to the pump and it does work. I put it in the car and no luck. I tested for power at the plug. With the key in the on position I get power to just one of the pins on the plug which correlates with the low fuel sensor. Should I be getting power to the side of the plug for the pump? I thought I read that it primes it but then only puts power when cranking?

If that is true it may answer my problem. The plug pins on the underside of the pump cover are corroded and perhaps that is wear the disconnect is. If that makes sense? Does anyone else think the problem may be in the plug? Pics below.




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Old Oct 12, 2019 | 07:49 PM
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That's the most common issue I've seen lately. That plug had almost melted on my car. I bought a pad they connector and wired the pump with that to bypass that plug.

Vince
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Old Oct 12, 2019 | 08:40 PM
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Originally Posted by Project88Turbo
That's the most common issue I've seen lately. That plug had almost melted on my car. I bought a pad they connector and wired the pump with that to bypass that plug.

Vince
I am thinking it may be the culprit, but can anyone explain to me why I wasnt getting power to the plug on the topside? Like I said I got power to one pin but not the others.
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Old Oct 14, 2019 | 08:30 AM
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When you key on the pump will run for like 1-2 seconds to prime and that's it. If you want to run it continuously, open the Diag box under the hood and jumper the F/P and GND terminals. With that jumped it will run the fuel pump continuously with key on.

If you aren't getting voltage, time to check relays and fuses.

Dale
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Old Oct 14, 2019 | 01:47 PM
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You may want to clean that gunk really good before you go checking your relays

There's also some good write ups on rewiring the pump. I prefer these two (and IRP's post on repinning the stock connector). You don't need to bypass anything (if you don't have a crazy amperage pump(s))

https://www.rx7club.com/3rd-generati...ewire-1124167/

https://www.rx7club.com/3rd-generati...mbers-1107704/
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Old Oct 14, 2019 | 02:27 PM
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Great info and threads. I cleaned up the plugs the best I could and will try again today. Hopfully I will have luck starting it and then do a proper rewire down the road.
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Old Oct 24, 2019 | 07:49 AM
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Update

Just letting everyone know the bulkhead plug for the fuel pump was no good. Once we bypassed that we were able to get the car started. Next will either be a new fuel sending unit or just a rewire with a new bulkhead.

Last question. Is the float arm on the sending unit supposed to have some resistance to it or should it flop around freely? Mine moves by hand without effort but if i move it up it will stay in that spot. Should it drop freely on its own?
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Old Oct 24, 2019 | 08:51 AM
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It should flop around. If you are moving it all the way up and it's sticking it may be going up past where it would normally top out at. Generally those senders are pretty reliable, only real problem I've seen it them getting rusted over in a car that sits for a really long time (5+ years).

Read up on doing a new bulkhead wire, some people have had problems with certain setups where it will eventually seep fuel at the connection. Also all wiring needs to be rated for submersion in gasoline.

Dale
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