91 F250 w/ 460 running rich

[Simp5782]

Ok so I picked up a 91 F250 4x4 with a 460 and a MT for $500. It runs, has around 135k on it. It runs rich as hell though. In an enclosed shop it will smoke ya out in around 2 minutes. Guy had looked at it but didnt want to bother with it so I took it off his hands. He has replaced the O2 sensor and the coolant temp sensor for the computer. Still runs rich as hell. The EEC connector isnt working and the scanner cannot contact the computer. it is the EFI engine which I know is a crap design and might as well swap it all for some carb and old D0ve heads, but I wanna try to get it up and going and just have a garbage run truck and something to beat the hell out of and not care. Not like I want to drive it across country. Cause the 460 is the king of **** poor fuel mileage. I have not worked on a ford with the old style computer dinosaur system in along time, quiet frankly I prefer my IDI its alot easier to diagnose.

Any ideas on where to start since I cant scan for codes and it will not flash any at all? Fuel is in good condition, good free flowing exhaust so I know the cat isnt clogged. Air filter is good and no intake restriction. Also cleaned the valve body and put in new plugs, but within 5 mins of running the plugs are so fouled they have to be cleaned.

I can post some videos of it tomorrow of what ive tested and how it runs at idle.

 

[93f250idi]

check all the fuses. bet ones blowed and thats why the scanner port doesent work. have had this happen on several vehicles. not sure what could make it run that rich unless the injectors are stuck open.

 

[Simp5782]

All fuses are good and I have good resistance between the scanner connector and the EEC connector so its in the computer.

 

[MUDKICKR]

i had a 92 f350 with the 460 do that. wiring had fried the computer. good luck. i converted it to carb after finding the price of the wiring harness and computer. also to wake up the 460 use a 429 timing chain

 

[Diesel_brad]

Calvin had a way to play with the timing, but he never got into details. I wanted do do that BEFORE i got my timing cover back on

 

[94f450sd]

check the fuel pressure regulator.pull the vacuum line off it and see if gas drips out of it or if it smells like gas.

 

[MUDKICKR]

Calvin had a way to play with the timing, but he never got into details. I wanted do do that BEFORE i got my timing cover back on

the 460s from like 74 on had there cams retarded like 4 degrees due to smog requirements, which ford did via timing chain. if you notice the crank key-way isnt straight up when its at top dead center.

 

[sassyrel]

check the fuel pressure regulator.pull the vacuum line off it and see if gas drips out of it or if it smells like gas.

second on this...as the diaprahm...will get a hole in it,,and flow right thru,into the intake,,hence damn poor mileage....and yes,it happens occasionally

 

[Black dawg]

check the fuel pressure regulator.pull the vacuum line off it and see if gas drips out of it or if it smells like gas.

check the fuel pressure also, they regulator can fail causing very high pressure and not leak out the vac. line.

 

[Simp5782]

figured it out today, had the fuel pressure regulator sticking, a crimped return line near the bellhousing, and 4 leaking injectors. Hince the 80psi fuel pressure was free flowing those leaking injectors.

 

[MUDKICKR]

thats awesome you got it fixed, and for cheap. i just ran across a deal on a 91 f350 with a 460/5 speed. runs great and was going to offer some parts up if you were interested.

 

[sassyrel]

figured it out today, had the fuel pressure regulator sticking, a crimped return line near the bellhousing, and 4 leaking injectors. Hince the 80psi fuel pressure was free flowing those leaking injectors.

sticking---now thats a unusual one,,tho murphy............................normally,,the interior spring gets weak,,and the pressure goes high,,or the diaprahm gets a hole in it,,and leaks gas thru hose into intake.....buttttt, you found it!!!!!!!!!!!!!!!