fuel syetem problem

[ctkallday666]

hey guys. im new to the forum. i have a 99% stock 96 f-250 with the seven three in it. only mod i have is a down pipe. im having problems however, my truck seems to be bogging down and even stalling on the road. i have a new filter installed and a 4 month old mechanical fuel pump. but now the truck just wont start. i took the filter out and i tried cranking it and it was cranking veeeery slow. the mech fuel pump seemed like it was hardly working. my truck has 280,000 miles by the way. any help is appreciated. thanks.
louis :fordoval:

 

[Tom S]

If they cranking is super slow it will not start as there is not enough voltage to make the IDM happy.

 

[Magnum PD]

Need a fuel pressure reading. Does the blow fill up after you crank for a little bit? Fuel won't go the pump again when the filter is out.

 

[ctkallday666]

thats what i was thinking. so what would i need to do to get the truck running again? i honestly thought i needed a new mech pump..

 

[ctkallday666]

Need a fuel pressure reading. Does the blow fill up after you crank for a little bit? Fuel won't go the pump again when the filter is out.

after a while when the filter was in i would try to crank it. but it wouldnt crank but it would actually crank normally. not slow or anything. but now i think its a voltage issue since it cranks very very slow.

 

[Magnum PD]

If it's cranking slow put a battery charger on it and get it cranking like it should. Crank for a little bit and find the valve stem on the side of the bowl and see if there is fuel pressure built up.

 

[ctkallday666]

isnt the pressure suppose to be around 65 psi? i cant remember. but it can be pressurized if the truck is just cranking right?

 

[Magnum PD]

Fuel pressure on a stock pump varies a lot. Bounces around a lot. Somewhere around 40psi

 

[superduty4x4]

Fuel pressure on a stock pump varies a lot. Bounces around a lot. Somewhere around 40psi

My stock pump runs 70-100psi while driving.

 

[purpleheart350]

Mine is between 50-65 psi

 

[purpleheart350]

My stock pump runs 70-100psi while driving.

You might want to look onto that you either have a bad unit or something cuz I don't think a stock pump should be making that much psi. I. Could be wrong but if you changed your pump which pump did you use cuz I might switch to that.

 

[superduty4x4]

You might want to look onto that you either have a bad unit or something cuz I don't think a stock pump should be making that much psi. I. Could be wrong but if you changed your pump which pump did you use cuz I might switch to that.

I know my gauge and sender are fine. With the old leaking pump it would swing between 20-70psi while driving.
I don't know if the pump is stock, or an aftermarket replacement but it's just the stock mechanical pump. Completely stock fuel system as well.

 

[purpleheart350]

Damn well if you ever find out what kind of pump it is post it up