01 f450 7.3 lacks power after 1.5 hrs of driving.

[Patrick_Hamann]

Hey guys, Complaint is that this truck will lack power after 1-2 hours of driving on the highway, 65-70 mph. A little background on the truck, it is a Charter Communications bucket truck, has a utility bed and is LOADED down. The customer states that you have to hold WOT to try and maintain speed uphill on highway. 310,xxx miles on the clock. I test drove the vehicle while monitoring inlet restriction and fuel pump pressure at the outlet of the pump, Inlet restriction stayed at 7 in. hg the entire time, idle, or wot. Fuel pump pressure stayed solid at 62 PSI. According to history the fuel tank, pickup and pump were replaced for restriction from rust/delamination 60k miles ago. max boost is only 13 psi. My question is would it be possible that the 7 in. HG of restriction be a sign of delamination even though fuel pressure never drops? Any help appreciated. i drove the vehicle for roughly 1.5 hours and I could not fully verify the concern.

[Brad Clayton]

7 is still a low enough number to keep looking for the problem that is plaguing this truck. A quick filter check can also help to rule out an imploding fuel tank. If it's real bad, you'll get some bits like this:

I doubt that's your problem though.

[Patrick_Hamann]

If I bring it in today ill pull the filter and check it out and let you all know

[Aaron]

Pull the sending unit out of the tank, and take the filters out of it, maybe the filters are plugged up?

[Bruce Amacker]

His inlet restriction would skyrocket. I've seen them pull 29 inches when the screens were clogged.

 

[Aaron]

Last one had the needle buried by the time I got back out of the truck after firing it up (stick truck, and I had the gauge bar hanging off the service body on the back).

 

LOL.

[joshbuys]

His inlet restriction would skyrocket. I've seen them pull 29 inches when the screens were clogged.

 

 

I've seen many, MANY trucks with partially plugged screens in the pick-up unit that cause a very noticeable lack of power with only 7 - 10"HG at the inlet of the pump. Just sayin'

 

[Jim Warman]

I think that you desperately need to get the concern happening to avoid grasping at straws.... given that there are that many miles on the truck, it could turn into a money pit for someone.

 

I'd be getting my customer to drive it for two hours or so before he brings it to me. Given that inlet restriction stayed at 7 inches whether it ran "good" or not (I wouldn't be all that content with 13 PSI boost), I can't see that being a progenitor.

 

Where is fuel pressure being monitored? How about ICP/IPR (are we looking at oil aeration?). Crankcase pressure? EBP? Has anyone gotten creative with the EBV?

[Keith Browning]

Exhaust back pressure sticks in my mind with intermittent power concerns on these. A catalytic converter that is breaking apart can cause this as well and something like that will screw with you if you are not sharp. Like Jim stated, you desperately need to diagnose this while it is happening.