Need help with Ford 351w troubleshooting

Sites

Well-Known Member
I finally got my 1994 Lightning running and out of the shop. So far so good, but I am having one major problem. After about 20-30 minutes of driving, if you give it any more than just a hair of throttle, it falls flat on its face and bogs horribly. The engine is stock and uses a Speed Density air metering system. So far I have repalced the EGR, EGR position sensor, TPS, IAT, and coolant temp sensor. The engine is stock with the exception of a K&N cone filter on the end of the factory intake tube. I pulled the ECU codes and there was nothing but transmission codes (I ditches the E4OD for a C6).

If anyone has any suggestions of what it could be, or possibly a good shop here in the San Diego area that could help diagnose the problem, I would appreciate it. I would take it to a Ford dealer, but I have yet to have a dealar diagnose a problem successfully.

Thanks,
Andy

94' Lightning Prerunner (in-progress)
 

Kritter

Krittro Campbell
You may need to have the computer tweaked since you ditched the trans. The transmission sensors communicate back and forth with the computer for optimal performance and since you ditched those...the computer doesnt know what to do. Is there a lightning with a 5spd? If so you should try to get that computer.

Kris
<A target="_blank" HREF=http://www.barneysprecision.com/fabproducts.htm> Fab Parts</A>
 

sirhk100

Well-Known Member
Andy,

Dieing to know... Have you hit the dirt with it yet? If so, how big was your smile!!!!! Last time I saw it at Rodd's place I was drooling!!! Any finished pics?

Khris

'92 Ford Exploder (AKA Dezert Limo cause it's loaded)
 

Sites

Well-Known Member
Kritter,

No, the Lightning only came with the E4OD. Any other ECUs I could use? Any Mustang ECUs? I'm thinking that once it starts acting up again, I will pull a vaccume hose to get the check engine light to come on (open loop) and see how it drives.

- Andy

94' Lightning Prerunner (in-progress)
 

motoxscott

Well-Known Member
Andy,

From what a Ford Racing tech told me, losing the E4OD transmission shouldnt effect the engine. Yes they are linked, but not to the point where one takes over the other sorta speak. It just throws out transmission codes. Maybe they were wrong. If the engine was going into a limp type mode it should throw some different codes.

Most Mustang ECU's are mass airflow, thats what they use when they convert the speed density F-150s to mass air. I'm not sure if the speed density mustang ecu's would work or solve your problem.

-Scott
 

Sites

Well-Known Member
Thats what I thought. When it does happen, it does not throw any codes (no check engine light).

94' Lightning Prerunner (in-progress)
 

motoxscott

Well-Known Member
Maybe it has something to do with the motor getting hotter. Possibly an air leak somewhere. With everything getting hotter and expanding, maybe it's opening up something somewhere, just enough to get it to stumble 1/2 throttle and on since the greater vacuum.

Maybe make sure the manifold, throttle body, etc are to the proper torque specs.

Will the motor stumble when in neutral and reving past 1/2 throttle? If so spray some conact cleaner around the manifold and see if that changes anything at different throttle openings 1/8, 1/4, 1/2, 3/4. Be careful not to spray to much as it is very flamible. It will tell you if you're drawing in additonal air.

Just some thoughts I had.

-Scott
 

tedmales

Well-Known Member
i would hook up a fuel pressure gauge and watch the pressure to see if you loosing pressure when it starts acting up, then maybe a vaccum gauge to see if a leak develops. good call on the egr system, that would have been my next guess. when it starts stumbling does it stop after a few, or just keeping doing it untill it cools off. if you have access to a scanner that will let you watch the pulse width of the injectors to see if they are not opening up when it stumbles that would help. maybe even a can of freeze spray on the ecm when it acts up to see if that helps. the first thin is to narrow it down to fuel or spark. then go from there.

life is too short to be small
 

CRAIG_HALL

Well-Known Member
Have you tried the Ford SVO guys I know you can talk to them on the phone,I know a guy that had trouble with his stand alone SVO EFI kit on his hot rod. The SVO guys talked him through the problem.
I'm sure a lightning motor has been put into many hotrods with a c-4 or c-6.
 

JrSyko

Jerry Maguire
Take it to Greg Woodington's shop. He is an off-road racer that races with Scott Douglas in BITD. His shop is out by San Diego State. He is great, honest guy that should be able to fix it for a reasonable price. Tell him Travis sent you.

Bowman's Garage
619-582-5258
Ask for "Woody"

War - the result of compounded stupidity
 

Sites

Well-Known Member
Travis,

I will give him a call sometime this week. I have spent too much time and money trying to figure out the problem myself.

Thank agian.

- Andy

94' Lightning Prerunner (in-progress)
 

vwguy

Well-Known Member
try to see if the tps sensor has the little tabs that catch the throttle body on the wrong side of the tabs. a guy i know put his on the wrong side and he would give it gas and it would want to die.

how ironic is it that most people slow down for speed bumps yet almost all of us here im sure pin it
 

Sites

Well-Known Member
Once I realized what the problem was, yes. Until I did, it was the most expensive trouble shooting EVER. I replaced just about every god damn sensor in the engine compartment.
 
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