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Discussion Starter · #1 ·
Here is the latest.
I tested my fule pressure regulator. It read 36.3 with the car not running. I put the tester after the fuel filter, inline. It seems to be fine. My fuel pump is pumping at 52 PSI as well, I know this is a little low but it should not cause this problem.

Here is my latest dilema. I recetly bought a mass airflow meter for the car. It is not new but I believe it to be good. The question I have is, the AFM has 7 male pins on it. On my wiring harness I am only using 5 Pins. The sixth and seventh are not there. I was told that California cars and Federal cars are different. One has seven pins and one uses five. Can anyone tell me with a great deal of knowledge if I should be suing a five pin AFM and not one with seven? The one I removed from the car had seven Pins. It was also messed with bad. It was completely torn apart and messed with. I don't know wether my car is Fed. or Ca.

Also, could my pressure regulator still be bad? I hooked the pressure gauge up to the return line to the tank. I had 60 psi of fuel pressure returning to the tank. Does this sound right?

Please help!!!
Tim Yardley
 

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Discussion Starter · #2 ·
>
> question I have is, the AFM has 7 male pins
> on it. On my wiring harness I am only using
> 5 Pins. The sixth and seventh are not there.
> I was told that California cars and Federal
> cars are different. One has seven pins and
> one uses five.

>I had 60 psi of
> fuel pressure returning to the tank. Does
> this sound right?

> Tim Yardley
Tim,
it sounds like you got an AFM from a earlier (75-77) 280. they used the additional 2 pins to turn on the fuel pump when the flap on the AFM was open. the 78 uses a different system with relays. it should still work on your car.
if you have 60psi on your return line i would say that you have a plugged line. this will cause very erratic problems with these cars. put an air hose to it and see if you hear bubbles in the tank.
good luck.
mike
 

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Discussion Starter · #3 ·
> if you have 60psi on your return line i
> would say that you have a plugged line. this
> will cause very erratic problems with these
> cars. put an air hose to it and see if you
> hear bubbles in the tank.
sorry I was not very clear when i posted this part. When I hooked the pressure gauge to the return line it was not inline. It was just plugged directly into the retun line from the pressure regulator. Completely disconnected from the tank itself. But after thinking about it. I might have a plugged return line. It would make sense. I have very little flow when the line is hooked up going to the tank. I can squeeze the line together like a straw. but when I disconnect the return line and shoot the return fuel into a container it flows real fast. Let me know what you think.
 

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Discussion Starter · #4 ·
Tim,
try putting air to the line or just blow thru it if you don't have compressed air, to see if you do have a plugged line. you can also try running the engine with the return line going into a 5 gal. can. just make sure that you have enough gas in the car that you don't run out.
mike
 

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Discussion Starter · #5 ·
> Tim,
> try putting air to the line or just blow
> thru it if you don't have compressed air, to
> see if you do have a plugged line. you can
> also try running the engine with the return
> line going into a 5 gal. can. just make sure
> that you have enough gas in the car that you
> don't run out.
> mike
Well, I don't have a plugged return line. I hooked a pressure gauge inline this time. I had no ZERO pressure goin into the tank even when running. I even blew through it with no problem.

I did put my old thermotime sensor back in and it ran a little better. I also went back to my old Throttle positions sensor. This was a big mistake. It ran even worse. Thick black smoke poured out. and it did not want to run. Like I said before, the TPS i have in ther now is from a 75 280z. I used an ohm meter on them both and the ressistance is close to each other. are these parts the same? Or maybe they are both bad. One worse than the other? they both have the same number on them. Obviously one is faulty. Any clues.

Tim Yardley
 
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