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77 280z fuel pump wiring/voltage

Old 07-10-2005, 09:11 PM
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77 280z fuel pump wiring/voltage

this is my first inj Z, fuel pump has 12 volts ALL the time.... key on... key off.... doesnt matter. obviously this cant be right, and explains the bad pump. after spending all day looking through the worthless shop manual diagrams i am lost. #1 problem, i cant find the relay, striped all the harness wraping off and chased the hot wire clear up under the mid of the dash..... i thought the relay would be on pass side near ecm, fuse block, etc.... but the wire doesnt go there.

so if somebody has an idea where the relay is exactly.... can ya chime in and give me a hint....... thanks
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Old 07-10-2005, 09:31 PM
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We had this question come up before. It's located on the inner fender, pasenger side near the strut tower with the other relays. It's not likely it failed in the on position. It was probably hot wired.
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Old 07-10-2005, 11:10 PM
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i did locate the inj & pump relay, located on the drivers side under dash, only thing on the pass inner fender is voltage reg and a 1 relay with 3 wires, under the fuse holders.

the voltage is being supplied through the engine relay....back through the pump relay. im guessing somewhere in the mess of engine compartment wiring i will find the connection to bat power.

is this a common problem for people to bypass whatever and hot feed the relay? as i said earlier this is my first injected Z.... i have had several 240's.... all of which were carbed....with simple wiring.
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Old 07-11-2005, 09:51 AM
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The fi cars started in '75 and were only similar in looks. The relays and fuses seem to be in different places each year and the Cali cars had even more stuff on them. Even the repair manuals conflict on some items. I think this greatly contributes to the Micky Mouse wiring I've seen on some cars. I have a '77 Cali parts car and I will try to hunt it down and get back to you.
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Old 07-11-2005, 09:24 PM
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There are a few relays just above the fuse box on the pass side kick panel.
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Old 07-11-2005, 10:01 PM
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It sounds like you have a 76. The ignition relay/fuel pump relay is sort of just above and off to the side of the hood pull opener handle. This is one relay with about 9 - 10 pins, and a black & white connectors. Make sure the black is on the bottom, as these can be swapped.

A 77/78 has seperate relays for the ignition, fuel pump, and a Fuel Pump relay circuit. They are located underneath the black sheet metal cover, between the battery and the front suspension strut on the passenger side (right side/ U.S. models).

Someone may have bypassed the relay, and installed a switch so that your fuel pump runs all the time, bypassing the fuel pump relay circuit?
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Old 07-23-2005, 09:58 PM
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Another place I would look is the Air Flow Meter, there is a pump cutoff switch in it. Just unplug the conector on the bottom and see if the pump cuts out(with the engine off). The switch should be open with the engine not running, once the engine is running it is closed. This is a quick check to see if the contacts a welded. Good Luck.
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