I know, I know. But before I go into details let me explain that I'm not expecting too much from this truck. This is my 3rd IDI. I've had a '84 6.9 and a '92 7.3. Both bone stock except soup bowl removed and stock muffler replaced with a glass pack. I was completely satisfied with the power output of both of those trucks.
But my newest one, the '85 6.9 just doesn't have much power. She's firing on all 8, all filters are new, fires right up warm and cold, and hardly any smoke. No soup bowl, same type of glass pack. Engine sounds great, except my previous trucks had a roar in the glass packs when revved, this one sounds more like a turbo muffler.
No maintenance history available, but she looks like she's got low miles, but not very well taken care of during the ones she's got.
I found a leak in my fuel line which I fixed, then a leak in the lift pump which I replaced. No change though. The water separator was full of water when I bought it so I drained it and replaced the fuel filter. Been driving the truck for over a year and it's been reliable and it can pull a good load, it just takes a while to get up to speed.
Any ideas?
TIA!!!

 

Take a look on the driver side valve cover and make sure that you don't have the 166 hp version.

 

Okay, I'll go check it out, but I thought the two HP ratings was for the 7.3?

 

oops, sorry I just saw which truck this was for, I thought it was a different year for some reason, but who knows I didn't know to recently that there was a 166 hp version of the 7.3, as in when I cleaned my motor and discovered I had one.

 

No problem, I appreciate the quick reply!
I just checked, and if I'm reading the sticker right, (some of it's hard to read, the VOID is bleeding through), there were two HPs available, a 158 and a 175. The 175 is punched out on mine. Also noticed the motor is an '87 so I guess it's been changed before. The truck is definitely an '85.

 

i like ur name ur sending unit might be going out nad not pumping the amount of fuel u need

 

It's prolly not timed correctly.