1991 f150 4wd 5.0 302.

it ran threw plugs in 75 miles, pass. side cyl bank totally carbon fouled. i have a severe lack in power and acceleration, gas and occasional flames coming from tail pipes (bbk short tubes, X pipe, 2.5 duals dumped after rear axle)

brand new cap, rotor, plugs, wires, tps, map, coil, a.i.r/egr/air condition delete, new air filter and modded air box.... ran AMAZING for 75-100 miles then it started missfiring on acceleration now it dumps so much fuel it takes me a good 45 seconds to get to 60mph.

during KOER self test when it comes time for the WOT test the engine dies....timing is good, no oil or water cosumption, but when accelerating i get a HUGE could of white steam/smoke that smells like unburnt gas (running VERY rich)

this truck ran great for 3 years with out an o2 sensor or any emissions but it sat for 6 months till i bought it off my best friend, like i said it drove great for a while.

no unusual codes, but i cant complete the self test or real me fuel pressure (threads on valve stripped)


and help would be appreciated, im running out of money and paitience

 

You need to figure out some way to test the fuel pressure and also look to see if the FPR is leaking fuel into the vacuum line.
What codes does it produce with the KOEO test? I understand you have the emissions components removed but what else is it flagging.
Do it have an O2 sensor now? If not get one installed.

 

no fuel i saw in the FPR line but ill check again.

using a ford OBD1 reader i came up with there codes

KOEO-
31 (egr/evap)
52(power steering (didnt do steering wheel turn test))
81 air system
82 air system

KOER-
21(temp sensor..i just put one in?)
22(map, also replaced this..and cleared codes after)
41 (HEGO_HO2S)
31 (egr-evap)
77 (didnt sense WOT for dynamic test...will elaborate more)
52 (power steering)



well code 77 in interesting. during a KOER test when code 10 is displayed on the code reader you are suppose to press the accelerator to WOT then release...well when i tried the engine instantly CUT OFF! "POP POP CLUNK" is all i got...it starts up and will run the test again. even if i dont try to floor it the engine still dies...almost like it getting cut off for gas.


i have no o2, but what i dont get is the truck ran for so long without it? why suddenly start throwing flames and spitting fuel out of the pipes.

 

Something changed obviously... there is a blockage in the fuel system or the regulator died and now fuel pressure is spiked high, or the injectors are stuck on all the time because of shorted wires(rodents chewing on stuff), or a complete computer malfunction. Considering this truck was sitting the chewed wires thing is a real possibility so you're gonna have to take a real close look at all the wiring, a fuel presure gauge would also help confirm this too because the fuel system should build and hold pressure before the engine is started, but if the injectors(even one of them) are always open it won't hold any pressure.

 

i pushed in the plunger on the fuel rail valve and it sent out a burp of gas, it seems like there should be more.


this is the 2nd ecu this truck has gone threw too :/

im going crazy man, this is really killin my wallet. i just checked and no fuel in the regulator val line but it sure does smell like gas.

and when the engine is idling i hear a whop whop whop instead of the classic ford sewing machine injector sound....or maybe im just trying too hard to find something wrong.

 

bump bump bump. i need this fixed asap. any help is appreciated

 

Honestly, it may be the computer itself. The same thing happened to me after I got done building my 94 with a 460. It ran fine for about a month, then started rocketing gas. A new computer has fixed it so far.

And as far as all your codes, the computer will never blame itself, it has no way to. So it will blame everything else and send you on a wild goose chase. I'd invest in a new computer once you've ruled out your fuel system.

 

thats what i was thinking, this truck is on its 2nd computer. i just had to ride my girlfriend to her mom's house and it felt like i was running out of fuel.....but i never actually ran out i just had to pump the gas to keep it going, i got up to 20-35mph doing this. could this be my fuel pump going bad? i have had fuel relay issues before..

 

Without getting a true reading on the fuel pressure you are shooting in the dark.

 

just put a new FPR, old one had ripped up o-rings but im still having the no fuel issue. i have a fuel pump i can throw in it and if its not that then i know its not fuel delivery.

 

He He....The codes my friend tell you the issue....I think

The EGR valve reduces emissions by re-routing a portion of the exhaust gas into the intake manifold
When not replaced, vehicles can experience poor engine performance, poor idle, high NOx emissions, failed emissions test, hesitation, engine surging, or CEL/MIL illumination

The EGR valve position sensor reports present position of the EGR valve pintle to the on-board computer
When not replaced, vehicle may experience excessive or non-functioning EGR valve, failed emissions test, high box emissions, surging at highway speeds, hesitation and/or CEL illumination

EGR vacuum solenoid works with the on-board computer to provide a calibrated vacuum source for the EGR valve
When not replaced, vehicle may experience excessive flow or non-functioning EGR valve, engine dies at idle, failed emission test, high NOx emissions, surging at highway speeds and/or hesitation

Okay, I have not read through the posts or looked up the codes. The EGR one is the only one I know off hand with out looking them up. Now It's time to do some reading.

 

its not the egr my friend, the egr system has been disabled for about 3 years with no ill effect, BUT i am glad you mentioned it because that bring something to mind, my egr tube goes under the upper intake into the head, where as i heard in these trucks it goes into the cats?

 

Actually the EGR tube goes under the upper and connects to the lower intake, but an internal port then connects it to the back of one of the exhaust ports in the passenger head.
The tube that goes to the cats is a fresh air supply from the air pump and has nothing to do with the EGR system.

 

durn i should have known lol. A.I.R system is gone too on this truck.

im getting really sick of having no power at low rpm under load. im NOT blowing white smoke (or at least not near as much) anymore after new FPR 7 fuel pump, but its still a dog in low rpm..what could this be?

the only things i can think of are:

-timing chain slipped a gear/stretched
-ECU gone (again)
-head gasket
-running so rich due to bad FPR&fuel pump fouled the plugs, and hurt other systems

 

bump. had another one of my buddies look at it (he is a mechanic and went to the same school as me) and he is stumped too! ugh..