I am having great problems with my 79 280zx. It will sit and idle fine all day but most times when you press the peddle the engine shutters and almost stalls. It also acts like it is backfiring through the intake. I recently replaced the fuel pump. I don't even know what to start checking with the fuel injection system. Any ideas would be greatly appreciated.
Thank You

 

I don't know too much about fuel injection cause I have a 70' 240. I think it sounds like you need more air. I think you can disconect the air flow sensor from the throttle body, but leave the wiring connected, then floor it and see what that does. It might be that you need a new one, or you just need a new air filter. On a carbed Z when that happens your air to fuel mixture is wrong or the plugs are dirty or bad. Your timing might have something to do with it. LIke I said I don't know injection but that seems logical to me.

 

It could be your throttle position switch, does it kinda bog down a bunch before it revs up, like it tried to choke and then hesitates? Well anyway, if it's the TPS, you have to adjust it, I"m not entirely sure of the procedure in a 280, but for a 300 you disconnect the plug and check the top 2 tines for continuity, and rotate the switch until it contacts... I'm sure someone can explain it better than that, but it's in the Haynes guide, and you can try that, costs no money to adjust the switch, if not that, then you can keep looking...

The Beast is back and badder than ever!

 

Mine did that and it was the air flow sensor. Try banging on the thing while the car is idling and see if the idle speed changes.

 

CHECK THE BOOT BETWEEN THE THROTTLE BODY AND THE MAS AIR SENSOR IF IT IS CRACKED THE ENG. GET'S
MORE AIR THE THE E.C.U. SEES MAKING THE MIXTURE LEAN.
ONEFSTZ

 

the same thing happens to my car let me know when you find the source of the problem i have a 1977 280Z

 

SKULLY
YOU MIGHT CHECK YOUR COLD START VALVE.
ONEFSTZ

 

unless you are in a region whose temperature is really low the cold start valve isn't used. It is most likely a air fuel mixture problem.

Killer

 

IF YOU LIVE IN ANY REGION THAT DOES NOT GET BELOW 71 F. OR 22 C. THAN IT DOESN'T OPERATE BUT THERE ARN'T MANLY AREAS IN CA. THAT THAT HAPENS.
AND IF IT ISN'T WORKING THAN YOU HAVE A MIXTURE PROPLEM.
ONEFSTZ