ok guys, im having some trouble and i need your help. i have an 89 f150 with a 5.0 EFI and a 5 spd tranny. about a month ago i took it to my uncle's shop because it was just barely running and the check engine light was on. first he changed the fuel pump because it wasnt feeding enough fuel to the engine. then he changed the exhaust manifolds because they were cracked and the engine was loosing backpressure thru there. he also found out that a few of my injectors need replacing, but he hasnt replaced them yet. then he hooked it up to a scanner to see if the computer was throwing any codes and it turns out the computer says theres an air restriction. he checked the whole intake and the throttle body and everything is working fine. the computer then started throwing al sorts of miscellaneous codes for things that were working perfectly fine. hes telling me now that the computer and the whole fuel injection needs to be replaced. what he told me was to think about it before making any desicions because he says it might almost be better for me to get rid of the whole fuel injection and put a carburetor on it. have any of you guys tried this before, going from fuel injection to carburation? what needs to be replaced? im looking for the cheapest way of getting the truck running again since ive already spent money on the manifolds and a new fuel pump, and i dont care if i have to get rid of the EFI to do so. sorry for the long post guys, but i really need your help here...thanks a lot!!!

------------------
1989 F-150 XLT Lariat: 2WD 5spd 5.0[*]3" Body Lift[*]33x12.50.15 BFG on 15x10 AR Rims[*]Rancho Steering Stabilizer[*]Rancho RS 5000 Shocks[*]K&N Air Filter[*]Flowmaster cat-back dual exhaust

 

sorry to say but you need to try a different mechanic
you find out its cheaper to fix the problem with the right diagnoses than to replace parts without proper testing
ps get a shop manuel to start with

[This message has been edited by fordtec2001 (edited 03-11-2001).]

 

ok so far ive had the truck looked at by 3 different mechanics and none of them can figure out whats wrong with it! they all told me that i am having problems with the fuel injection system and they think its the computer, but none are sure! i dont want to spend my money fixing something that doesnt need to be fixed. how can i be sure? another thing, when the engine is at high rpm's, a huge cloud of black smoke comes out of the tail pipes...what does this mean? is it burning oil? man, i am really getting anxious here. anyone have any ideas or had any similar problems? any input is greatly appreciated...thanks a lot

 

That black cloud usually indicate a rich mixture, considering the problems you are having with the computer, I'm not surprised. I wouldn't worry about the smoke, it will likely go away when you get the other problem fixed.
It does sound like a computer problem, that would also cause the EFI to look bad. May I suggest, before ripping out the EFI, go to your local salvage yard and get another computer. It's not as expensive as new, so if it doesn't fix the problem you won't be out too much (Won't be more than $150), but I believe it will cure your problems. A buddy of mine has a 89 Cheroke (sp?) that was doing the same thing, bogus codes, running like crap, 45 mph tops. Got a used computer, running like a top for more than 2 1/2 years.
Good luck.

 

Donate
The mid-80s 302 had a nylon or nylon-tooth timing set that were known for quicker wear-out. Either you or your mechanic might set the balance wheel on the timing mark & check if the distributer rotor is pointing to the #1 on the distributer cap. If spark & cam timing are off, that would make the computer to get real bad inputs. You are the second pre-90 with similar probs today.

------------------
97 Lariet-sc-4.6-4x off road-auto-3.55 LS-
superchip-Airraid-Perma-cool electric fan & controller

 

we just checked the timing and it is fine. do you guys think it could be a clogged catalytic converter? thats what my dad just told me it could be. what are the symptoms of a clogged converter on these trucks? i think im gonna have the catalytic conveter checked, and if its ok then im gonna see if i can get my hands on a cheap used computer. any other suggestions? thanks a lot for your input guys!

[This message has been edited by Donate54 (edited 03-15-2001).]

 

Glad that wasn't the prob, Donate. I would have the catalytic checked-you could probably cut the exhaust off in front of the catalytic & see if it runs OK. If not, I would try the ignition module( gray box on the side of the distributer ). I've bought 3 computers and they were never the problem, but it's possible as a last resort. I am baseing these ideas on what I have encountered.
Jeff

 

Ok here's the update...
I finally figured out what the problem was, the first catalytic converter is clogged (i forgot to mention the truck has 2 catalytic converters one after the other). my buddy and i cut the exhaust pipe right after the cat and gutted the cat to see if it would run, and it did. right now i haven't welded the pipe shut yet, but the truck is running really rich. could it be the oxygen senors? there is 1 sensor right after the cat i just gutted. do i need 02 simulators or will it go back to normal when i have the cut in the pipe welded back together?

[This message has been edited by Donate54 (edited 04-08-2001).]

 

let me guess that cat's monolith was melted? this would be caused by the rich mixture - check your map sensor - a ford dealership can test it on the sbds

 

Don't overlook a bad fuel pressure regulator. They are real bad about causing rich running problems.

------------------

2000 XLT Bright red, Flareside,extended cab,sport,5.4,bedrug,Extang tonneau.