Ok guys need some help I have a 95 f350 5.8 5 speed 4x4 origanly got the truck with bad blow by I freshened up the motor (which at the time was the 5.8 lightning motor) would run good in till warmed up then would shut down and wouldn't start till cooled down well never figured the problem out and a rod bearing started making noise will trying to figure it out so I have up on that motor figuring that was part of the problem

So I got a regular 5.8 from a junk yard put it in runs great but still when I go to take it for a spin when it gets warmed up ( about 5 miles) will just stop running if I keep it in gear it will try to stay running but as soon as I give it any throttle shuts off won't start in till it cools down or give it a shot of starting fluid will run fine and get me back home if bin towed home many times till I figured out the starter fluid truck

So when it shuts down and won't start I have spark, good fuel pressure, fuel pump is kicking on (both fuel pumps are brand new), coil has power injectors have power just won't start unless I give it a little help with starting fluid but after it starts with that I can shut it off and it will start right back up no problem

So I have had 2 different motors in this truck with the same problem I'm planning on trying the computer next I have also changed around the relays and no diffrence any help will be appreciated

 

Also to add the truck seems to be running pretty rich could it be flooding it or fouling out the plugs and that's why it will fire back up on starting fluid if so what would cause this because both motors seemed to run pretty rich ?

 

Start by checking for codes.

 

Many times this issue is the ignition control box.

 

Ok so I got a chance this morning to look at the truck again only code coming up is 128 and from what I read that's for a map sensor and this truck dose not have a map sensor and the old motor didn't have one either now I do have a buddy of mine on his way with his f250 we are going to try and plug and play a little with computer and ICM see if either of them are the problem all help is appreciated thanks for the replys

 

How does a '95, F350 not have a MAP sensor?

It's Speed Density not MAF.

 

Yes sorry that would be my miss interputation I think I may got it straighten out one issue is the fuel gauge read wrong says 1/4 tank when it's empty ran out of gas in my drive way today and second there was no vacume line from the intake to the MAP sensor I just had it idleing in my drive way for about a half hour now with no hickups helps us having a second truck to compare things to when the wife gets home I will take it down the road and see if it quits on me now that I have that vacume line hooked up I haven't gotten any codes hoping that's all it was thanks for the input guys

On another note if anyone in the northern pa area is intrested in a set of gt40 heads and lightning lower intake and upper intake possible even the whole motor I would sell it

 

Does your F-350 have two intake tubes all the way into the air box, or does it have two intake tubes that converge into one tube with a large metal sensor bolted to the airbox lid?

 

Only has the 2 intake tubes into air box no MAF sensor truck is running good now I have put almost 100 miles on the truck since put the vacume line from the intake to the MAP sensor thanks again for the input greatly appreciated!

 

Well atleast it was an easy fix

 

Well go figure I put around 200 to 300 miles on it so far and did some running around this morning with it got home it sat for about an hour. Went to leave for work and it dose it again. check engine light didn't come on so about 5 miles away same place it always dose it slight incline on the road I give it throttle in 5th gear and it cuts completely out. let of the throttle runs fine give it only a little throttle runs fine. so I turned around head back to the house only did it intermittently it acts like it's completely losing fuel or spark but it's not completely shutting down like it was doing before. both fuel pumps are brand new Front take is full rear tank about half tank tryed both tanks still did it. got to my road and got into her a little and ran fine. drive my jeep to work I'll see if it dose it again tomorrow will be hard to diagnose it when it's only doing it when driving it. I'm wishing it was a little newer I could hook my laptop up to it and run my AE program while driving it if you guys have any ideas please give your opinion thanks

 

you said that you have good fuel pressure, but you didnt say how many psi.
also, does the fuel pump prime for a second when you turn the key and then stop, or does it keep running ?

 

primes for a second then stops running around 32 to 35 psi while running when it's not running first turn the key on hits roughly 60 or 70 can't remember off hand then comes down to 40 and stays there

 

That is not correct behavior. You should verify what your fuel pressure actually does because it should never go above 40 PSI at any time.

 

Just verified it no longer going above 40 it hits 40 and comes down to 38 when running at cold start it sticks right at 32 as the motor warms up it starts jump around from 30 to 34 as I rev on it it climbs and to 40 in a steady motion then returns to 30 to 34 is a pulsation if I unplug the vacuum line it moves to 42 I also unplugged the MAP sensor vacuum and it started to run like **** then smoothed out a little I have new plugs, wires, cap and rotor I'm going to put them on still the same from the salvage yard and later I'm going to the local scrap yard I'm going to grab a few things MAP sensor pressure regulator ICM computer and possible a few others there free so don't hurt to have spares if I don't need then if you guys think of any sensors to try please let me know and I'll grab them while I'm there