Guest fattyjay22 Posted February 17, 2004 Share Posted February 17, 2004 I have a 76 280z which I think has a bad fuel pump relay. I can start it fine, but once I turn the key to ON, it slowly dies from lack of fuel. Currently I have just hot wired the fuel pump, but really need to get this resolved. Does anyone know what type of universal relay should I use to replace my old one? Is it timed or just a standard one???? Or have I missed somesort of evil Datsun trick? Quote Link to comment Share on other sites More sharing options...
datsunlover Posted February 17, 2004 Share Posted February 17, 2004 I have a similar set up (thanks to the previous owner of my car ) and my pump runs constantly now. I'd be interested in the solution to this too! I think this 'hot wiring' has affected other things too.. I have the dredded 'bogging/sputtering over fueling a$$hole datsun' problem too... Quote Link to comment Share on other sites More sharing options...
Guest fattyjay22 Posted February 17, 2004 Share Posted February 17, 2004 I just rebuilt my motor and made it home from DEQ just before it went out!!! I have a 10.3:1 motor and I am running a constant 37psi from my fump at all times!! At least I have a pressure reg to keep the pressure down. The anti-theft feature is very nice though!!!! Quote Link to comment Share on other sites More sharing options...
Guest fattyjay22 Posted February 18, 2004 Share Posted February 18, 2004 Ok I think I have answered my own question!!! After quite a bit of searching in this GREAT SITE, I came across a post that kind of delt with what I need. The last Entry on the forum answered my question. And I quote from member (Nismo280zEd) "I agree the 25 year old mess of wires on the Z is not very pretty, make your life easy... go to autozone or whatever car parts store you have, buy some 35 amp 5 prong relays (generic) and just wire in new relays. That way you have clean wires you understand.. and your saftey protection." Thanks a bunch guys, now lets see if I can figure this out Quote Link to comment Share on other sites More sharing options...
spotfitz Posted February 19, 2004 Share Posted February 19, 2004 Unfortunately, the ignition/fuel pump relay also ties into the thermotime switch through another relay(which is located just above the ecm, under the dash.) So wiring in new relays maybe alittle harder then just replacing the relays with a factory one. My PO decided to bypass the ign./fuel relay altogether, which gave me virtually NO cold start ability, because all these relays also tie into the cold start injector and air temp sensor(same relay above ecm). Come to find out the PO couldn't find the problem, which is the reasoning for the bypass. After chasing the wiring harness and my tail for several days I was able to eliminate the ign./fuel relay as the problem(which is where his bypass was located). After several more days of the same thing I found the other relay was the problem. Checked it with a friends relay of known working order and then replaced it from one I picked up from All Z's and everything has been good since. I would recommend putting a relay inline for powering the fuel pump, but replacing the two relays(which actual perform about 6 functions) with seperate relays for each function may not be beneficial. Quote Link to comment Share on other sites More sharing options...
Guest fattyjay22 Posted March 8, 2004 Share Posted March 8, 2004 Well, I guess my relay was fine. The problem was the FUEL PUMP CONTACT POINTS in the AFM. All I had to do was remove the cover and clean the points. Now she runs like a CHAMP!!!!!!! Hope this will help someone out there!!! Quote Link to comment Share on other sites More sharing options...
zmaster Posted April 2, 2008 Share Posted April 2, 2008 so if the thermotime switch doesn't work does that mean the fuel pump will not turn on at all? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted April 2, 2008 Administrators Share Posted April 2, 2008 so if the thermotime switch doesn't work does that mean the fuel pump will not turn on at all? The Thermotime switch has ABSOLUTLEY NO control over the fuel pump! Zmaster, for the LOVE of GOD, GET your Haynes manual out AND TRACE the wiring!!!! Quote Link to comment Share on other sites More sharing options...
zmaster Posted April 2, 2008 Share Posted April 2, 2008 I hate tracing wires....I hardly have any time to trace wires because I am doing the body work, and getting ready to pain in a few weeks when the weathe warms up a little bit more. Quote Link to comment Share on other sites More sharing options...
spotfitz Posted April 2, 2008 Share Posted April 2, 2008 so if the thermotime switch doesn't work does that mean the fuel pump will not turn on at all? I wasn't implying that the thermotime switch was your problem. I just stated that it is apart of the wiring to those relays which also control several other functions. The Thermotime switch has ABSOLUTLEY NO control over the fuel pump! Exactly. Quote Link to comment Share on other sites More sharing options...
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