Ok,here comes alot of info.

I have an 86 F 1-50 extended cab,2 fuel tanks,auto,2 wheel drive,EFI 5.0 litre,new rear end,new I-beam,motor,trans,drive-line

I thought it was fixed after I changed the coil,after sitting all night it started rough then smoothed out after a few seconds,the coil fixed this.

the motor has 65,000 on it,the timing chain went bad after hauling a ton in the back over the rockies.

I have changed all 3 fuel pumps,in tank and external,changed the porcupine valve between the tanks,the high pressure regulator,plugs,wires,rotor,cap,distibutor,module.

The EEC relay is not hooked up,a mechanic in Vegas bypassed it all and ran straight vacuums 3 years ago,and it ran fine till now,the map sensor is/has to be hooked up,the knock sensor is also unplugged.

After doing all this it starts/runs fine until you jump on the gas,it hesitates and doesn't want to go,if you let off it accellerates as long as you do it easily,its almost like something is blocking the fuel,or maybe the spark? (all filters have been changed too).

I have noticed white trails on the inside of the distributor ap where the roter touches it,also black dust on top of the rotor where it touches the cap,after about a week new plugs have a black dust on them too.

I am mechanically minded,love fords,all i've ever drove,i've put ALOT of money into this old truck but can't understand what i've missed.

Does anyone have any idea what i've missed?

 

Did you try your EGR valve? I know they can make them run funny.

 

The map sensor is one of your most important sensors. If it reads low(the vacuum is low because you have the throttle plate wide or nearly wide open), and the engine rpms are low(signals from the dist), then the computer will add more fuel to the engine. The map sensor is the only way the computer knows how much load is on the engine. The throttle position sensor works with this also. You also should have a vacuum line going to the fuel regulator. When the vacuum goes low, it raises the fuel rail pressure to also add to the amount fuel injected to the engine.

I can't believe all this stuff was bypassed, and the engine was expected to run correctly. All that stuff needs to be hooked back up. If you do not like that idea, then rip it out and put a carb on it.

 

No,I guess I didn't write that very clear,the map sensor is hooked up,as is the regulator and everything else,what he bypassed was the black box by the map sensor with all the little multi-colored vacuums coming out off it,the sensors are all hooked up,and i'm beginning to suspect the EEC relay,because in the past you could hear the external fuel pump power up,but not anymore,does this make sense?

 

Well I also just checked the fuel pressure off of the fuel rail and its within tolerence,so maybe the evp sensor off the egr valve is bad,everytime I do something it gets better,so maybe i'm on the right track,any suggestions would be appreciated though.

thanks.

 

I would hook a code reader to it, and see what codes you get. If it's a simple problem like something's not hooked up, or not functioning, the computer will pick that up right away and give you a code.

You can use a testlight or old meter with a needle if you like to get the codes, without buying a code reader. This site tells you how to do it.

www.fordfuelinjection.com

 

Yeah,thats exactly the problem i've had,can't seem to find a mechanic here with one of those,had a great one in texas,and nevada,been to some local shops here in oklahoma city,they don't know,went to a ford dealer today,he had 50 cars ahead of me, told me they wanted to keep it a week (sigh),

Oh well,I appreciate everyone's input

On a lighter note ANY REFERRALS FOR A GOOD FORD MAN IN OKLAHOMA,please send me their way,they will have a repeat customer.

 

Just thought i'd write what the outcome was to all of this,in case anyone has problems like these.

The knock sensor was unplugged and it wasn't letting the timing advance at high rpm's,didn't realize this,I unplugged it over a year ago,it just now started all my problems.

Thanks for the advice,i'll keep this page in my favorites.