Ok, here's the deal. For some reason, the fuel pump stays running when I turn the key to the "on" position. Doesn't shut off. I'm assuming it's that way with the motor running, also (which would explain my recent problems). So far, I've switched out almost all injectors, and the FPR (borrowed from Wildman). While I was out there today, I capped off the cold start valve (never worked anyways), but haven't tried it as of yet (frustrated). Ya'll know I've tried a different ECU (same model). My WTS isn't reading correctly (infinite ohms), but I've disconnected that while running before and no difference. CHTS ohms out ok. It seems that the FPR is releasing the fuel back to the tank for some reason, but I'm not sure if that's where it's actually going.

Your help is greatly appreciated. I have no money to "hit and miss" on this one, so let me know what to try....

Thanks

Carl

 

Hmmm That Is Wierd, Wish I Could Help You On That One.

 

the fuel pump not shutting off could be that the system has a leak, its not reaching its shut off pressure of "xxx" psi value or a weak fuel pump that is bypassing the fins. get a pressure guage on there and check it out, running (koer) and key on engine off (koeo) should be like 36 ish.

 

I was just reading THIS article. See what you think. I had no idea you could get the pump to come on by playing with the AFM flapper while the key is "on". And Shady, yeah, I need to get a PSI guage...

 

That article was a good find Carl... Nice job.


rod.

 

Thanks, Rod. Hopefully it will help my problem and some other people's as well...

 

When you turn the car off the pump is not still running right? As far as I know when you have it "on" but not started its supposed to be on. I could be wrong but mine always hummed in the "on" position.

 

Yes it's off when in the "off" position, but when you turn the key to the "on" position, it's supposed to run for only approx. 5 seconds, then shut off til you crank the car. Mine just keeps running in the "on" position without the engine running...

 

Mine always ran to.. Oh well not like the injectors are firing its just gonna go back LOL

 

Well at least your fuel pump works. That is kinda weird though that it would stay running. Do this to it

 

Sounds like a fpr and/or ecu prob. The fpr should allow pressure to build up & stop the pump if working properly. The ecu should be programmed to turn off the pump after x amount of seconds when the engine isn't running. All the Z31 ecus also control the fuel pump (the 280zxt has it's own controller). The ecu controls the pump by grounding the signal to the fuel pump relay... I don't have a Haynes Manual with me at work... but does the 280zx n/a ecu do the same? Check the manual for fuel pump relay wiring.

This gives me an idea... we could swap ecu's. I have my 81 n/a still (I believe). We'll check on ability tomorrow.

 

Don't ask me why, but while out at the car, I tapped on the air regulator and the pump stopped. Checked out the pigtail and the two bullet connectors and they're all dirty (pigtail is mucho greeno!). Gonna clean that mess up and see what happens...

Carl

 

Already tried an '81. No pump worky. Thanks anyways....

 

Sorry, that 81 ecu idea was for fdc_guy.

 

No problemo...

Well, I did some ground cleaning on the manifold, and FINALLY got the pump to start acting the way it should. Car started and ran well for awhile. Now I'm about out of gas. If it ain't one thing, it's another...

 

great to hear you are getting some results

 

Well, here's the kicker...turns out it was all just a simple bad ground right on top of the manifold. It's the one closest to the nipple thats hose goes over to the center connection on the carbon canister. Loose bolt and dirty as hell. So that bad ground was causing the fuel pump to run constant and flood the engine (or something). SHEESH!! What could've cost nothing more than five minutes of time turned into a month long shithole and cost me close to $50, that I still owe on. Oh, well, the knowledge I've gained throughout this ordeal is priceless (red, tired eyes not withstanding). Also, have an extra ECU to back me up just in case. Still using my original. Cars running **** again, but I do need to invest in some good plug wires when I get some money in...

Thanks for ya'lls help, and CHECK THOSE GROUNDS!!!

Carl

 

Yeahhhh Carls Back In Buisness!!! Glad You Have That Spare Ecu As Well.

 

Right on Carl, knew you could do it buddy. Well as they say: "You learn something new everyday" Holds true for that one eh? Anyway good job, and get some fuel, and give your Z a run man.

 

Thanks all. Wildman, I didn't have to use any of your injectors, so I'll return them as soon as I can afford any gas. I would like to keep using that old FPR I found on your bench for awhile if possible, until I can afford a new one. Those things are WAY too pricey!! I'd appreciate it. If I can just get my last check from my old job (bastards), and sell the wing and maybe the louvers (I think I'll donate the '79 ECU to the Smithsonian ), I'd be good to go until my new job starts to pay. That could be up to 3 weeks, though...

Thanks

Carl