S14 fuel pump inop

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ca18det_boy
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Joined: Wed Dec 24, 2003 10:47 am
Location: Homestead, FL
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So after spending a couple days hunting I figured I'd go ahead and pick the brains of others. 1996 S14, RB25, wiring specialties harness, fuel pump inop. The chassis had a running VH in it a month ago with zero issues. I've been searching the internet for days and thus far I'm stumped and it doesn't seem like anyone else has had a similar issue.

Pump won't prime/run. I've verified good grounds at F14, F15, T16, M5, and M57. 12V going to the relay, 12V going to the pump assy. I've swapped ECU's 3 times, swapped pumps, tested pumps, swapped relays just for giggles, and still nothing. Pump is a drop in replacement Aeromotive 340 and I've also tried the Walbro 255. Factory wiring as far as the chassis is concerned. I know the pump is ground triggered by the ECU, but I don't know how I still can't have fuel after trying all these things. I've attempted to contact wiring specialties and that has not been fruitful. Can anyone think of anything that I might be missing?


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centralcoaster33
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Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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If you simply bypass it all with a 12v jumper, will the pump work and the engine run? That would be useful in both diagnoses and as a crutch.

ca18det_boy
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Joined: Wed Dec 24, 2003 10:47 am
Location: Homestead, FL
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So I've found the culprit. Wiring specialties had the harness wrong. Pin 18 (relay ground trigger) was in pin 33's spot (exhaust temp sensor). Repinned it and now there's juice.

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centralcoaster33
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Joined: Tue Apr 05, 2005 10:41 am
Car: 240SX #5-1997
Location: Central Coast, CA

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So, they employ humans. That's good news. Even better is that you found and fixed the mistake! Did you have to swap some others around as well, like the exhaust temp or anything?

ca18det_boy
Posts: 1384
Joined: Wed Dec 24, 2003 10:47 am
Location: Homestead, FL
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Exhaust temp is N/A since it's in an S14. It was/is frustrating dealing with them...but I have my own opinions and reasons. What happened between myself and them is going to stay that way. I don't want to air out dirty laundry here. I haven't tried to fire it up since I verified voltage to the pump. I'm hoping to hear it fire tonight, but if one thing was wrong then there might be something else wrong also. I'm keeping my fingers crossed that there was only one mistake.


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