Hello all,
I recently put a new long block (302) and auto trans into my 91 f150. Got it back and it ran horribly. Stalling, no power, black soot pouring from the tailpipes and 4 mpg when I could keep it running. Checked the fuel pressure regulator and it was bad. Replaced it and truck stopped stalling, but still had terrible fuel mileage and no power. I advanced the timing quite a bit by ear to compensate. Checked the o2 and it was shot from the regulator dumping fuel. Changed the o2 and map sensor. Fuel mileage went up to about 9 mpg and it is driveable at freeway speeds now, but still smells rich, and doesn't have the power it had before the swap. Does anyone have any ideas because I am fresh out! Would over advancing the timing rob me of power?

I've sunk over $4000 into this truck to have a strong running and reliable pickup at this point and i am worse off than before. I would really appreciate any advice or thoughts you might have. I'm at my whits end at this point.

Thanks All,

Jack

 

Any time you replace a sensor, disconnect the battery for 5 mins. I would run error code scans first, at least the KOEO scan if possible. Replacing parts w/o E/C scans is like making all your shots from the 3-point line. After you're now knee deep in replacement parts, it's tempting to think your shot percentage has to improve because there aren't that many left. But, $22. will almost painlessly get you a lot closer to making the right shot. A real time & money saver! http://www.handsontools.com/Equus-In...ol_p_5574.html You can do in manually, counting flashes, but for a few bucks, digital numeric display w/ memory! All fords 81'-95 EEC-IV/OBD-1.

 

I'm gonna get one of them for my 92, do you think that I should get the extension?

 

If you have an extra $22., burning a hole in your pocket. Not required, but nice to have!

 

I've tried running both the koeo and koer using my Solus Pro. And it tells me that there is no power detected at the harness. I forgot about pulling the leads though, that's a great idea. I will try it and post results. Obviously, there's a break in the wiring harness leading to the obd1 connector, I will also try running that down when I get to the shop tomorrow.

Thanks for the feedback! Keep 'em coming please, neither I nor my mechanics can figure this one out. Does anyone know the flash sequence for pulling the codes through the dash ?

Thanks again!

 

Ford Fuel Injection How To Run a Self-Test Here is how to pull the codes without a code reader if that is what you mean.
I would also check for a restricted exhaust (plugged cat), if not already done.

 

Thanks, I appreciate the info and the link. To your knowledge, will over advanced timing cause the kinds of issues I am talking about?

 

Too much timing could hurt power but it would be from preignition and that will be audible.

 

I don't hear any knock, and it's not missing. It just is way under powered. I'm going to try to pull the codes tonight.

 

So could not enough.