2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

No voltage to fuel pump?

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Old May 15, 2005 | 03:08 PM
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From: Ephrata, PA
No voltage to fuel pump?

My most recent problem has been the car starting and then immediately dying. I thought this a vac leak and proceeded to tear apart and replace/retighten everything from the TID to the UIM/LIM gasket. I thought this would fix everything but I went to start it, it again caught and immediately died. I check my MAF, and it is in spec, and then went to the fuel pump. I can't get any voltage to it. I jumped the check connector (the two prong yellow one by the passenger strut tower right?) and I still didn't get anything. So this leads me to two questions...

1. Should the check connector leads be continuous? Mine were really oxidized and I couldn't get the multimeter to beep.

2. Is it a fuse or something that controls the fuel pump? I had been having hesitation problems before it decided to just not start, so something must have gone progressively bad, no?

Thanks for any help! Also, its a complete S5 TII conversion.
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Old May 15, 2005 | 04:35 PM
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From: Coldspring TX
Could be one of the coils in the circuit opening relay is bad (the one fed by the AFM door or jumper). The other coil is energized by the key's start position, so we know it's good...

As a way to troubleshoot this, jumper the middle black/ white to the blue wire right beside it at the base of the relay (under the dash, next to the steering column). Use a piece of solid wire, like a paper clip.

Note that the pump will (should) start to run as soon as the key is turned to on (much like the jumper wire on the connector).

If this fixes your problem, then the relay is bad. If not, get back to us
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Old May 15, 2005 | 05:26 PM
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Ok, I jumped the relay under the dash by the steering column (its black and yellow with 5 plugs right?) and got some relays clicking and the pump to turn on. So I should assume that the relay is my problem? What is the best way to fix this? Can I just permanently jump it or should it be replaced? Thanks for the help so far.
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Old May 15, 2005 | 05:34 PM
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I had the same exact problem, that damn thing is loud when it clicks. Make sure you have the brown and green wire going to your AFM connected to a ground, that is what triggers the relay, if that sucker isn't getting a ground signal it won't do ****, I went up and down my wires and still couldn't find the problem so I just ran a fused 12v to the fuel pumps blue wire (iirc, ill have to get back to you on that one) with an oil pressure safety cut out switch in line, it all works great now, alot safer too
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Old May 15, 2005 | 05:42 PM
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From: Coldspring TX
Originally Posted by jdmsuper7
Ok, I jumped the relay under the dash by the steering column (its black and yellow with 5 plugs right?) and got some relays clicking and the pump to turn on. So I should assume that the relay is my problem? What is the best way to fix this? Can I just permanently jump it or should it be replaced? Thanks for the help so far.
The relay is the problem, IF the pump wasn't running with the connector jumpered, and IF she stays running now once the key is let go from start. There is a slim possibility it could be the wiring, but I'd shoot for the relay first...

Don't jumper it permanently- it's the same scenario as leaving the connector jumpered, if you get into a fender-bender and a fuel line is ruptured, the pump will keep running, instead of shutting off with the AFM closing as it should...
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Old May 15, 2005 | 05:48 PM
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From: Allentown Pa
Thats Why I installed the oil pressure drop switch, when the oil pressure drops drastically or it cuts power to the pump, got it from summit was like $11 and hooked it up to a t-fitting off of my oil system

Last edited by rx7 punk; May 15, 2005 at 05:52 PM.
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