i had the identical prob with my 92 f150 4x4, took 4ever & $$$ to figure out. tried everything, see if u can borrow a computer to try and see if yours is cooked. i had a cracked windsheild that leaked down on the computer and fried it caused all the same symptoms. i ended up having to get a brand new 5.0 because of it, started with a cracked windsheild. check if u have fuel in your oil

 

Sounds like you tapped into the problem. The ECT tells the computer whether the engine is cold, warm, or hot and adjusts the fuel accordingly. Still would check all other avenues.

 

I agree that this would affect the way it runs, but to a certain point. That sensor will just tell the computer the engine is cold, which is when the computer will richen up the fuel mixture. The computer is not going to make it run rich to the point where its blowin black smoke though...

 

It's definitely - has been for a long time - running rich.
Fuel pumps? or injectors?
Maybe the computer?

 

With it losing pressure instantly after its been shut off, this leads me to believe that you have an injector problem. My truck has 217,000 miles on it and I havent had a problem with te injectors, and it will hold pressure for a while. I think it drops 10 LBS every 5 minutes...

 

Could the pressure loss also be from the fuel pump check valve?
What other problems could the bad fuel pump check valve cause?

 

Could the pressure loss also be from the fuel pump check valve?
YES

What other problems could the bad fuel pump check valve cause?
THE FUEL TANK MAY OVERFLOW OR SPEW FUEL WHEN THE CAP IS REMOVED.


Which injectors did you use? The 22# or the 19# ?

 

They were rated at 21#.
From Summit Racing.

 

I think the check valve is inside the fuel tank. I've never had to deal with it (phew) but there is a way you can narrow it down to see if its Check valve or Fuel injector related:

Remove the Fuel Return line from the FPR. Get a small piece of hose and put it in place of the return line. Block the loose end of the hose with an object. Now cycle the key to ON a couple of times and see if the fuel pressure holds. If it does, the FPR and injectors are in working order and the problem lies within the check valve. If it doesn't hold, its the injectors.

Also, if this was an 'ECT stuck on cold' problem, you would sure get code 21 on KOER. I would get the same temp. Thermostat.

 

Great suggestion!
Thanks!

 

I plugged the outlet from the FPR and my pressure gauge held 40 pounds for at least 5 minutes. At least I know the injectors aren't leaking!
If my logic is correct, then this problem won't directly effect the running of the engine. Right?
I think I'm ready for a new ECM!
What else would make the engine run that rich?

 

Hello guys or gals as the case may be I am new to this forum but not new to the problem posted here. I have a 1989 F-250 Lariat with 197000 miles on it. It was well maintained, my problem is intermittent, starts ok sometimes, stalls, blows black smoke after cranking while holding throttle to floor. I replaced the FPR, was told it could be the TPS, happens warm or cold. any help would be appreciated

 

also forgot to mention check engine lite comes on sometimes and oil press reads low end until i restart then reads ok engine runs ok for awhile

 

Diskguy - wrong injectors, sorry. The truck 302's use the 19#. Also, check the vacuum at the port on the fuel pressure regulator. When you disconnect it the fuel pressure should jump about 10psi. How much vacuum do you have there at idle?
I'm thinnking wrong injectors and a small vacuum leak are leading to excess fuel injected.

2dogowner - Welcome to Ford-Trucks!
visit www.fordfuelinjection.com to learn how to pull the computer codes. Start a new thread when you post them please.

Peace
Tim

 

Bummer news!
I'll look into replacing them with stock Ford injectors.
I have 33 pounds of fuel pressure and 21 inches of vacuum - both at idle.