i recently just got a 1985 f150, it has a fuel injected 302. However it is not running right, it will start up and idle kind of fine, but high (around 1100rpm) and is not very responsive at all off idle and will ocassionally backfire and misfire through the intake upon giving it throttle..

so this is what i have done
-drained old fuel and cleaned out tank(because truck was sitting for awhile)
- changed fuel pump inside tank
-cleaned out fuel lines
-changed fuel filters (including lifetime one)


also after the truck is completely warmed up (about 15 minutes of idling) it will completely shut off and will not start until it is cold again...

the truck acts as if it is running out of fuel but it has great pressure after the boost fuel pump..

i have about 20 hours into this truck.. and still have no idea what it is..
feel free to ask me any ?'s im sure i left out alot of details

 

no one has any ideas?

 

How long has the vehicle been sitting? Mileage?

You have taken care of a piece of the puzzle. I would say that your next step would be wires, plugs, cap, and button. Your modual could be bad as well, on the side of the distributer... MILLIONS of things can be wrong with a truck that has sat for a length of period at it's age.

When you let it idle till it shuts off, and it won't start back, test to make sure you are getting fire at that time.

 

the car has been sitting for about 6 years however it was ran atleast once a month. it has 60,000 on the body and frame but only 20,000 on the motor.. my dad is CONVINCED (he is a mechanic) that it is fuel related. just because it idles and then acts like it is running out of fuel

 

I am convinced that FUEL is only part of the equation. But, just for fun, make sure your fuel pressure is up to spec. 85 is when Ford trucks got to be FUN (so to speak for not wanting to use fowel language) to work on. PLUS, with the motor transplant and then the truck was parked, means only one thing... You inheritted something, some one else couldnt fix... Just my opinion.

Then, go for the AIR, FIRE, VACUUM theory.

6 years is a LONG time for one to be sitting. Wires have dry rotted, vacuum hoses have dryrotted. Plugs could be shot. You get my point I think, but, I could go on all day because there are MILLIONS of possibilities with this. And unless YOU were the one supposedly STARTING IT once a month, don't ASSUME that it had even been started at all. LOL After all, you are working on a truck that DON'T RUN right? LOL

 

Sounds like Vapor Lock to me.. that can happen in recprocating engine aircraft if your not careful.

 

so now the truck doesnt run at all anymore. so i replaced the fuel pump (high pressured/ boost pump) and no luck.. however i did disconnect the intake box and spray starting fluid into the throttle body and it started right up... any help would be appreciated, because i want to start driving this truck soon

 

Might try using a fuel pressure tester just to make sure.. Then I would get the Haynes/Chiltons book and go through the basic trouble shooting..

 

truck doesnt have a schrader valve to test it.. however i just talked to my dad who is a mechanic and he thinks that it could be what ever times the injectors has gone bad

 

You will vapor lock one fast with starting fluid.

The modual on the side of the distributor could very well be bad.

 

then why does it start and idle when i spray starting fluid into the throttle body?
it is obviously not getting fuel, as i can crank the engine over for hours and it wont start but the second i spray some starting fluid in the throttle body it runs great.. so im thinking w/e times the injectors is bad..

Also where is the pcm located on this truck