- 1989 F250
- 351 Windsor 5.8L motor.
- Fuel Injected.

Hi folks. Like the title says, it's not idling? It will fire up and run at higher RPMS, but dies when I let off the gas. Pumping the gas pedal helps.

Any ideas where to start? Something to get me started would be appreciated.

Thanks!

 

vacuum lines. check for cracks, unplugged, and anything else that is vacuum controlled. the smallest leak could send it crazy.

 

Thanks for your response. I went out and looked for vacuum leaks but couldn't find any.

It's really acting like a fuel problem. Can anyone tell me how to check the fuel pressure? It doesn't seem to have a fuel rail like my Jeep.

Thanks!

 

Fuel rail right on top of the injectors has a schrader valve twards the back.

Pull the codes to start even if there isn't a check engine light. If you don't know how, check http://oldfuelinjection.com/ for instructions.

Use a haynes manual to check the resistance of the throttle position sensor, and the idle air controller.

Adrianspeeder

 

Ok ... Can't find any vacuum leaks.

- I took off the IAC and that was in good shape. All moving parts were free and smooth, and the Ohms test was in range.

- Chilton's tells how to test the TPS, but doesn't tell you what the resistance range should be! Anyone know the right number of ohms for my vehicle?

I took the codes, and here is what I got:

KOEO (Key On, Engine Off)
22 - MAP/BP sensor out of self test range.

CM: (Continues Memory)
29 - Insufficient input from vehicle speed sensor.
33 - EGR valve opening not detected. (Another source says: "throttle positioner sensor noisy/harsh on line")
41 - HEGO sensor circuit indicates system lean (right side) (The other source says: "oxygen sensor circuit indicates system always lean")
87 - Voltage was not detected on Fuel Pump Monitor while the engine was running. (The other source says: "fuel pump circuit failure")

It seems to me the most important one is #87 ... the fuel pump. Does that mean the fuel pump is shot? If so, which fuel pump? (there are 2).

Any further advice you can give would be much appreciated.

Thanks!

 

how do i make a post here? I have a 92 F150 with a 351W. It sat for a couple of years. I drained the tanks and put in new injectors, fuel filter, pressure regulator. When i give it gas it seams to sputter and back fire. Idle is fine. When i flip back and forth from the front and rear tanks it seams to help some. I can drive it 12 miles to work just fine but on the way home it starts to sputter and act up like the fuel pumps are going out. This has been going on for months. Could there be a problem with the ECU or a bad sensor?
Please help.

 

Hi Fiddy: Thank you for sharing. To create your own topic, you go to the category (here: https://www.f150online.com/forums/pre-1997-models-51/) and press the button, "New Thread."

Since your truck is idling fine, it's not a good idea to post your separate problem on top of somebody else's problem. That's called "highjacking" a thread. I know you didn't do this on purpose, but it's frustrating to ask help for a problem, then watch your question get ignored while people help somebody's else's problem posted in your thread. Make Sense?

Anyway ... if you go to that link I gave you, and start a new Thread, I'm sure you'll find some help you need. Welcome to the forum.

 

Ok ... I found the specs for testing the TPS and it was fine.

The problem was the MAP sensor. I tested the IAC and TPS ... both were fine. tested the MAP and it was way off. $50.00 at NAPA for a new one and 5 minutes to swap it out. Truck is running like new again.

I guess I should have tested the MAP first, since it was the one that threw the most obvious code.

Thanks for your help!