Hello,

I recently acquired a 76 280z with the big six and fuel injection. I was told the car had a bad fuel pump. Well after a lot of reading and testing....figured out that the power/fi relay was bad. I replaced it, and now the car starts, but it will only idle for 20 -30 seconds then die. I have purchased both the chiltons, and haynes manuals, but don't have much on the FI. I have gotten the 280z fuel injection theory and troubleshooting book, but it keeps referring to the service manual which I don't have. Basically though, what I am seeing, is that the fuel pump only runs when cranking, even with the AFM propped open, the pump stops as soon as the key releases to on. I also suspect that the injectors are never powering up, and that the car is running only on the fuel coming off the cold start valve. I also can completely disconnect the control unit, and it has no effect on the car running. Anyone have any ideas on which way I should looI am getting worked up enough that

Thanks in Advance

Ignition relay? Unless that's what you're referring to as the 'power/fi relay.' Also, check the electrical part of the ignition switch.

I think we are talking about the same relay. It is the one that takes 2 plugs right by the cotrol box uder the drivers dash. The one in there is brand new. I hink the physical ignition switch is okay, as I get heater fan, wipers, etc.

There are also a couple of fuel pump related relays in the box by the shock tower under the hood. Also, if it runs for 20-30 seconds, the injectors are working as there is not enough fuel in the CSV to sustain that long of a run.

Presuming that you are hearing the injectors clicking just before shut-off, my thoughts lean towards air flow sensor. My son and I rebuilt a 78' and once we were half way between Birmingham, and Nashville in 35 degree temp and stalled out after we filled-up with fuel. Later he told me that he had inadvertantly jared the sensor lug (at the front drivers side area of the engine compartment) as he was tinkering around looking for "the" problem that stalled us out. It would start after cool down, run 20-60 seconds(badly), then stall again. We replaced 4 fuel injectors, and 2 cans of "Heat" trying to remove the condensate that we were sure was contaminating our fuel. Anyway, just a thought. sometimes that lug gets corroded, and resistance builds-up.

Could be something simple like the fuel filter. When was the last time you changed it? It's possible that it could be severly gunked up and its no longer doing it's job filtering the fuel so any "Crud" could be bypassing the filter and clogging up your injectors. Just a simple thought.

By the way, have you looked for any possible vac. leaks? Our Z's are touchy that way. They will do the exact thing if the Oil Cap doesn't get put on tight for example.

Best of luck.

datsunZ's rule... where did you get your paintjob... its like a twin to my 77'. i thought it was my car for a second... holy crap!

glm, i think the problem is the fuel pressure regulator. mine did the same, ive gone through what you are dealing with, and that fixed it for me!

Thanks 28oz. It's actually a GM Blue the orig. owner had it repainted back in 1988. It's held up damn good Yeah, Royal Blue is one of my favorites on a Z

Here is a better picture of my baby Can't wait to get her out of storage ;-)

nice.... i want your rims... drool.....

Thanks. Yeah Panasports Look so awesome on classic Z's.

Your Z looks very nice too from what I can see.

P.S. Sorry gkm if we took over your post Let us know what you find out.

There are also a couple of fuel pump related relays in the box by the shock tower under the hood.

Stephen-

That location is correct for your '78, but earlier years had them up under the drivers side dash.

http://www.classiczcars.com/forums/showthread.php?postid=90125#poststop

Wayne