My 7.3 seems to go through stages of power loss ...
Cold engine seems to run the best.

As it heats it develops a lag, it doesn't like to accelerate to fast through 1st gear and almost seems to run rough especially if I am easy on the gas petal.
Then all the sudden sometimes 1/2 way through accelerating it decides to smooth out and gets a little bump in power.

At stop lights it seems to surge forward or almost idle rough and sometimes it will just all the sudden smooth out and quite down, almost like it goes into an economy mode.. ha.. almost!

I'm a new owner and I'm trying to get things sorted out so it can become a reliable work van.

I have gone through the engine and tried to tidy up some loose ends, tightened up the turbo clamps and cleaned out some of the oil in the intake tubes. Changed fuel filter(which wasnt to pretty), New battery, new air filters, will change the oil this weekend.

What else can I do to get this running top notch ?

Diesel additives ? Could I have a blocked injector or clogged injector ?

Only have 153K on the motor.
starts pretty well and doesn't blow any smoke, that I can really tell.

 

The exhaust backpressure sensor and tube on the 7.3L Powerstroke engine is prone to clogging up with soot and can affect performance and mileage. If your PowerStroke seems to be loosing mileage economy, this may be an item you should put on your list of "things to do".

 

Sounds like maybe a sticky IPR (Injector Pressure Regulator). If you can get hooked up to an advanced monitoring tool such as an AE so you can monitor ICP (Injector control pressure).

 

Ok -
1)Clean Exhaust back-pressure sensor and tube.
2) Check Injector pressure regulator, Monitor Injector Control Pressure. Use an AE.

 

Low fuel pressure will cause a lot of these symptoms you described, especially running best cold. You could have a clog somewhere in the system which could be between the tank and fuel pump (blow air through the line toward the tank to try and clear), a weak fuel pump, a sticky Fuel Pressure Regulator (FPR) which is attached to the side of your fuel bowl, or maybe a clogged up fuel filter or fuel bowl. Since it's a new truck, I'd definitely replace the fuel filter if you haven't done so. While in there, look in the bottom of the fuel bowl to make sure there's not a lot of sediment in there. If so, you'll need to take out the fuel bowl "innards" to clean it out thoroughly (it's easy).

As mentioned, make sure your IPR nut is securely in place too. That will cause all sorts of crazy surge and power issues.

OH, and Welcome to FTE! Make sure to put your location in your profile so it will show up. Someone from here may be close enough to stop by and help you diagnose! Don't give up on your truck yet...you'll fall in love with it soon, I promise!

 

A picture to show where the ipr may help him out... And me I'm not sure where it is either..... I have a big power loss also but nothing similar to the op I added a fuel pressure gauge which is always a smart move after the usual first 3 gauges. Mine reads 72 psi at idle

 

Here are some locations. IPR is located just below and towards the DS of the fuel bowl.



This is what the IPR looks like out of the pump, and it's components that can be referred to at times, such as the "tin nut"



To the OP's question though.

Fuel pressure and condition
Oil level and condition
Boost and drive pressure leaks to the turbo
Injector orings
EBPV sticking or being actuated
Low ICP(Injector Control Pressure)
Weak HPOP(High Pressure Oil Pump)
Bad or biased sensors
much more...

These can all cause or be evidenced by low power.

 

I saw your fuel filter, tank internals would be my absolute first priority.

 

Ok WOW -- You guys have clean motors ! haha

Mine is a oily dirty mess from years of neglect most likely.. and it drives me crazy!
Also I have an E350 so the motor looks a little different.. or i guess I should say the Layout is different.. stuff is in different locations.

YES!! THANKS for the Diagrams! At least I know what I'm looking for now !

Ok ... Ill keep it updated as I progress...
Waiting for a little warmer weather to dig deeper !
Hard to work on stuff when its 15deg!

 

Hand spray on some 'Simple Green' or Dawn dish soap to start breaking down the crud. If you use water, cover Alt and try to stay away from the electrical connections and use very light water pressure. And then wipe...wipe...wipe....

 

This is some good advice...I haven't seen your fuel filter, but I can tell you that the key to a healthy diesel engine is clean fuel and clean air. Neglect either of these two things and very bad (and costly) problems are going to pop up.

 

7.3 Bulletins Page
Updated: 6-4-08



Lack of Power, Trucks with Steel Tanks:
Some trucks may have a lack of power due to low fuel pressure from a plugged fuel filter or in-tank pickup tube, or restricted fuel lines. This could be caused by the steel tank lining becoming de-laminated/flaking off. If this occurs, the tank will need to be replaced, along with the plugged components. Be aware that using biodiesel with more than 5% concentration (B5) may cause this to happen. The replacement tanks do have a more resistant coating to help prevent this occurance, however Ford still recommends using no higher than B5 biodiesel. Broadcast Message 6865, 7103.

 

Lack of Power is a pretty common complaint that has numerous factors which could be causing it. In fact, there is a complete symptom chart (#10) in the Powertrain Control/Emissions Diagnosis Manual that goes on for seven pages. I could photograph the pages later today and send it to you...PM me if you want me to.

 

The more I've thought about this, the more convinced I am that you have a bunch of sediment in the bottom of your fuel bowl. 10 years ago a guy here in town was practically given a 1996 F350 CC DRW 7.3L by a friend (sold it for something stupid like $2,500), because it would barely idle and a lot symptoms like you described. He pulled the fuel filter and saw that the bottom of his bowl looked as if it was full of Kitty Litter. Cleaned it all out, replaced the filter, and Voila! Ran perfect. Cost him $15 for a filter and an hour of his time to clean it up thoroughly. And now he had a dirt-cheap (pun intended) truck to run around in!

 

I went to a Powerstroke class, sponsored by the dealership. They didn't have drums and sticks, they used gongs and baseball bats: Clean air! Clean oil! Clean fuel!