[Zmech14]

i have a 76 280z when i turn the key it starts right up for about five seconds then dies. I thought about the injecters but i had just rebuilt then so it wasnt that i had a friend listen for the fuel pump, we both found something tha puzzled us as your turning the key the fuel pump runs but when we let off the pump doesnt run. any ideas what could cause this would be much appriciated


thanks,
Zmech14

 

[Tony D]

Very Common, AFM!

Your AFM has a set of contacts inside it actuated by the flap movement. If these contacts are not closed, your fuel pump will not run. Sometimes it will run, then idle down, the thing opens, and the pump shuts off, then it speeds up agian and it just continues this cycle.
See if by BARELY propping the AFM door open you can keep it runing. Mind you, if you pop it too far open, it will make it run like crap or not at all. With the key in the "on" position, you wshould hear the fuel pump come on and run as long as the door is propped open.
Set your idle up and it may help with the stalling problem. I just went through this on another car, but that's another whole different story...
Right GhostKilla?

 

[johnb510]

Re: Very Common, AFM!

TonyD sound right on the mark. Test the afm, may have to clean the wiper contacts in the afm. Easy to do, just have to be carefull. Remove the cover to the afm, and slide a small piece of paper under the wiper on the card and move the flap with the paper under the pointer. Do not lift the pointer or disturb it in any other way... you may have to move the small piece of paper to the other side of the card. Replace the cover, reseal with silicone adheasive (very important step!).
But, before you do that try TonyD's advice and adjust the idle speed and see if that helps.
And as I said a million times before, a factory service manual is the most important tool for you Z. Using the information in to to test the sensors, ect will keep you from buying unneeded parts and keep for guessing at the problem.

 

[adam280]

I had a very similar problem to this on my 1979 280zx. The fuel pump would not start unless you hit it with a spanner with the key on. After letting some pressure build up I'd start the car, and it would run as you said then it would die because the pump would stop pumping. I fixed the problem by replacing the fuel pump, the old one was just worn!