Hey,
I just bought a 1990 5.0 302. It was sitting in some guys yard for at least 4 years, so I've had to change out a few things. I changed the rear fuel pump, and pinched off the lines to the front tank until I get a new tank (the old one was too rusted to use). The truck started right up and ran fine for awhile, but now it's starting to have issues. I'll explain the symptoms and hopefully someone will be able to help me out.
First, it would only bog down when I was going up a hill in a high gear. I'd press the gas in order to get up the hill without downshifting, and the engine would act like it wasn't getting any gas. First thing I did was fill the tank up, and it seemed to run fine. I figured I put the fuel pump in wrong.
Then it started happening with a full tank, same symptoms.
Now it's happening all the time, even under almost no load.
I've checked the fuel filter, it's fine.
The codes read that the TPS is bad, but I tried to check it and I wasn't sure which wire was which. So, I just unplugged it and the truck ran great for about 10 miles. Then, the same thing started happening.
Could the TPS cause a problem like this? A friend of mine said it might be the catalytic converter, or maybe the auxiliary pump.
Any help is greatly appreciated.

-Kolby Matson-

 

First off you do not have an auxiliary pump.
It does not sound like catalytic converter.
When you changed the Fuel Delivery Module did you look in the tank and see what it looked like?
If there was a lot of junk in the bottom of the tank the sock on the inlet of the FDM may be getting clogged.

The TPS if it has a dead spot and the voltage from it goes to zero or very low voltage the computer will think you took your foot off the throttle and you would lose power.

I think with that code for a bad TPS I would go ahead and change the TPS.

Here is some information on the TPS:
http://fordfuelinjection.com/index.php?p=30


It would be a good idea to put a fuel gauge on it and tape it to you window so you can see what it is doing as you drive it. Could save you a lot of money.

 

Can you explain that last line better? I'm not sure I understand what you mean.

Thanks for your input.

 

Sure. the line read:
It would be a good idea to put a fuel gauge on it and tape it to you window so you can see what it is doing as you drive it. Could save you a lot of money.


When you have a problem and take it to a dealer they will tape a fuel pressure gauge to the windshield that is hooked to the fuel rail. Then they will then test drive the truck and watch the pressure gauge. If the gauge says you have the proper fuel pressure when the problem occurs that will eliminate the fuel delivery system as the problem or confirm it.

Then on the other hand if you throw parts at it, say a two new FDMs, regulator and a filter by not using the gauge and it turns out in the end to be say the TPS then you have spent about $800.00 on parts that you did not need.

 

Thanks for the reply. I'm going to try that tomorrow.
I changed the TPS today, it didn't fix the problem. But it was giving codes for it anyway, so I guess I needed to change it.