91 f-150 Problems...

[coolen]

Good day to all. I'm hoping this is in the correct spot and that someone can assist me.

My father has a 91 2wd with the 5.0. Recently the truck's fuel pump was not shutting down after the prime phase. After some troubleshooting I took the computer apart and found 3 bad caps. I unsoldered, and resoldered in good ones and that fixed the problem. Yesterday we went for a drive in it, and all of the sudden it started loosing power (engine light lit), popping through the intake, and some blackish smoke started coming out of the exhaust, it also loss all power. And the popping starts with a load on the engine. For example, climbing a hill. It made it to our destination and back, thank goodness!

Long story short, I figure the truck is running lean, and this condition is only happening after the truck warms up. I also noticed that at idle, when the engine light comes on, the truck's rpm climbs to approx. 1200 then when the light goes off, it drops back down to normal.

I proceeded to ground that single wire to read the codes with the truck off but key on. If I read the flashes correctly, here is what I got:

72....MAP?
73...TPS?
33...TPS?
54...IAT?
and possibly a 63....

I have not checked the fuel pressure with a gauge as of yet, however it does spurt out of the Schrader valve.

Where would be a good place to start? The abundance of codes has me at a loss where to start. However, the MAP and the TPS has been replaced approx 2 yrs ago. Although I know that they could still be the problem.

Thanks

 

[rusty ol ranger]

Black smoke usually indicates rich.....but the popping sounds like a timing issue...you didn't mess with the distributor or anything did ya?

 

[coolen]

Good day,

Thanks for the reply! The timing was not touched, but I had the FP tester on it, and it showed it at 36psi...

I changed the filter today and no change. Fuel pump??

Thanks!

 

[rusty ol ranger]

Its hard saying. My experience had been either the fuel pump works or it don't. I'm not sure what the spec is....but its pry in the neighborhood of 40psi. So I'm not sure if 36 would be OK or not....I'm by no means an efi expert.

To me though by the symptoms its showing really sounds like its running pig rich.....pull a few plugs and see if their fouled....