Anyone ever hear of a stock lift pump overheating? Mine sure seams like it is.... This is on a untouched (except for exhaust) 92 ctd that makes 17psi of boost max (normaly runs 5-10psi on the flats while towing).

I replaced my old one about a year and a half ago. Everything seams good for a while but as you drive on the interstate the fuel pressure slowly goes down. I start with 4 psi under load after it warms up and after 50-100 miles it will sometimes go down to near zero. The harder you are working the motor the worse it goes down. If you let it sit for 20min or so it will have good fuel pressure again.

The fuel filter is not the problem. Loosening the fuel cap doesn't give an immediate benefit but I think it helps some on the long term. Lately I finally got fed up with it and lowered the tank to look at the pickup screen and it is clean. Plus there isn't any junk floating around in there.

So this led me to thinking I got a bad lift pump. But the new-new one does the same thing

I am going to throw on a vacuum gauge and run it for the trip this weekend (90 miles each way). Anyone have and idea as to where the restriction might be? It has the original plastic fuel line that looks in good shape so I don't think that's the problem. I know it has a complex fuel pickup system...could something in there be causing a restriction?

Thanks for the help and ideas.
ROB

 

this may not help much but i had problems with several stock lift pumps pushing enough fuel, went to the case dealer and but on a low pressure piston pump and problems ended.

 

Something you may want to check before spending any money is the filter screen on the in-tank sender basket. It's pretty fine mesh and yours may be all cruddied up. Could be letting fuel through at a rate to keep the truck running but slow enough that it could draw down under heavy load, fill back up when not. Just a thought.

 

From the original post:

He already did it.

 

I already did.... but didn't take the unit appart and am now thinking that it might be something with their fancy fuel pickup unit.

Was that with an unmodified truck crewcabxlt? This pump has a year warranty so I guess I could just keep replacing it untill I found one that worked. I just don't see why a stock pump woulden't keep up with a stock truck.

 

Related slight hijack.

I found that the priming level on the side of my stock pump moves but doesn't seem to do anything. Like totally slack/disconnected.

I've never had to use it, but if somehow I ever needed to I'd like to able to.

Anybody familiar with this problem?

 

Dave, I believe that if the cam that the pump rides on is at a certain position, the primer won't work. Try bumping the starter for a split second and see if that helps.