Hey ! Just signed up and bought a 86 F-150 XL , 83k clean from georgia truck. I love it , just have to finish making it run right. The day after I bought it, died out like it was running out of gas, restarted 25 minutes later, made it almost home haha , would not restart had it towed home. Pulled codes 14 and 63 . Code 14 brought me to the failing PIP sensor erratic spark/ distributor was shot and had a lot of up/down place in the shaft. Replaced the dizzy with a complete Napa unit, plugs were black beyond fouled truck seems to run really rich. Someone already removed the smog pump and capped off the ports on the back of the heads.

New Parts: Distributor w/ PIP coil and TFI module. Ignition coil, plugs/wires/cap/rotor.

Fuel pressure is at 38psi KOEO and Running, pulled Regular vaccuum 40 psi constant.

Truck starts right up and sounds not bad but will get you stranded, no power under load ,stalling , coughing revs , the more throttle the more it chokes and dies out ESPECIALLY under load... Made it home literally 8mph after the test drive... thought i was screwed !
I have to check if the code 63 is still there, TPS might be bad as well.
I'm led to believe the cats are clogged , it seems to be running so rich I doubt they survived. (snow bank is pitch black) I doubt fuel pumps are the problem but who knows. Truck has 2 tanks, i plan on changing the canister filter in the diverter switch soon along with the second fuel filter. Some people have had the same bogging issue and fixed with a new HP fuel pump. I need to run the codes again now. any suggestions ?? the truck is totally kick *** im not giving up. Thanks!!!

 

any tips in the right direction are greatly appreciated !!

 

Sounds like you're computer controlled and I don't know much about that. Hopefully someone who knows more than I will happen by.

But from reading these boards the trouble usually starts when changes are made to the emission systems. Then the computer spazzes out and goes into limp mode.

 

I can't remember off hand, but I don't think the pressure should be that high. The first generation of EFI on these trucks are crazy simple, as long as everything's dialed in right (helps if you keep notes of what everything's supposed to be). Any modifications to the engine? There are some things that are beyond the tolerances of the stock computer.

 

FP sounds right.

Check it when it acts up. Also check the filter in the fuel reservoir. The bottom unscrews and there's a paper filter in there. Took a while to find it in the parts store as they keep defaulting to the frame filter.

Pn:E6TZ9365A Motorcraft FG855

Replace the O2 sensor and the ECT sensor, the one for the computer. The early computers don't always set codes when stuff goes bad.

 

O2 sensor can cause these symptoms for sure, though I've never heard it as bad as you describe. When mine went bad (on my '92, which is nearly identical to the '85/'86 system), I unplugged it and disconnected the battery for ~30 mins to reset the KAM. Been running perfect ever since and all my emissions equipment has been tossed as well. The o2 sensor is the least needed sensor in the whole system, you'll notice no ill-effects whatsoever with it unplugged, it'll just throw a code intermittently. ECT sensor can make it run rich if it's reading a low coolant temp. I think IAC can be ruled out. TPS could be out of spec indicating the throttle is open further than it actually is, that'll cause it to dump more fuel in, as will a faulty MAP indicating a false load. Onto actual hardware, FPR could be leaking fuel into the intake, easy way to test is to pull the vacuum line off with it running and see if fuel pours out. Could be leaking injector(s), this is unlikely if all plugs are fouled, however.

 

twotonebullnose, i am having the same problems. i will let you know if i discover anything that works. please update us if you make any headway. i had almost wrote the problem off to my motor being worn and bought a fresher motor to standby but was running fine before fuel pressure regulator went out. replaced and still has same problem. i will try the O2 sensor unplug perhaps today if possible and let you know if it works.

 

sounds good mate ! im going to try to test (ohm) the ECT , also will try unplugging the O2, need to run the codes again as well. Also going to look into replacing TPS (since i had 63) and both fuel filters. Oh if all fails will be unhooking the exhaust to see if there is restriction from the cats.

 

Great responces and info here, I appreciate the help on this forum. thank you.

 

Sounds entirely possible and unbolting the exhaust is a bit cheaper than replacing parts. Cheap and easy first, if possible.

 

If you go this route though, definitely make sure that o2 is unplugged. Any stray breath of fresh air to the sensor will make it dump a ton of gas, that's why mine is currently unplugged.

 

Update : havnt been able to drive anywhere, still runs like crap , stumbly idle , stalls after a big rev , no power under load ... still think the cats are clogged. blows a crappy carbon -y whitish smoke when reving , smells aweful (and trust me im a car car , the fumes dont bother me - but this is def something wrong, lingering clouds ) and black smoke at idle , runs very choppy , exhaust does not smooth coming outta the tail pipe.

ran codes . pretty sure i got 21 , 23 ,24 , 63 .
23 and 63 point to TPS so ,
I unplugged the TPS and O2 , didnt make much difference .


i ohmed 4 injectors on the drivers side, all came to mid 15K ohms

 

ANOTHER UPDATE... well , after doing the blink test in a hurry, im geussing i got a code 22 , not 21.. that would be MAP sensor, located pass side fender well behind battery, followed the plastic vacuum line and it IS broken.
Going to give that a shot and report back!

 

Had all these symptoms, only remedy I could do was, Pull off 51 pounds of emissions crap,
Install an Edelbrock 4v intake and carb.
Turned the key and purring like a kitten. (CT has no emissions testing after 25 years).
Nothing worked trying to fix with emissions on......

 

Yup , still runs like trash. even with map and EGR lines replaced , runs smoother and more power but still runs like total dog.... poppin backfired when revved and wont idle after a while just runs lower and lower rpm until it stalls.