Fuel pressure question

[JEFF]

I installed a '78 280z fuel injection system on my '72 240.

the fuel flow is strong - but seems to be returning to the

tank in high volume due to the sound of it re-entering the

tank. The engine starts for a moment then dies. I think it is

starting for that moment on the cold start injector- but if the

fuel pressure regulator is not holding pressure wouldn't it

be a reason it would die? Question is: What should the fuel

pressure be in the fuel rail? And where is a good place to install

a fuel pressure port to check the pressure? Any thoughts would be appreciated.

- Jeff

[Walter Moore]

I have never even seen the fuel injection system on a 280Z, so it is ok to call me "brittle" on this subject...

But, on my 1974 Volvo 164E you adjusted the fuel pressure by attaching a mechanical oil pressure gage to the system in place of the cold start injector (it had a hose...) and jumpering on the electrical fuel pump. That gave you a clear reading of the pressure in the injector rail.

I doubt that I can be much more help than that. I recomend that you buy a manual if you intend to pursue it much further.

[JEFF]

Walter Moore - I did find the pressure in my manual today.

The pressure should be @ 30 psi at idle - 37 psi at any rpm

over idle. Thanks for your reply -

- Jeff

[sjcurtis]

Jeff

one of the things about the early Z is the small diamiter return line. this could be messing with your fuel flow, that fuel pressure look for 35-38psi constant at the pump. Check your return fuel via the pressure regulator functional check. Remove the vacum line to the pressure reg blank the manifold end listen for any change it should get rough and maybe smokey, but you should get some change, no change, change out the regulator.

Hope that helps.

my 2c

Steve :classic:

Edit:

Jeff I thought of an obvious fault, EFI wiring from computer, start wire and run wire crossed over so you get minimum start fuel, but full rich fuel when running with start mode off .