99 power stroke low on power :-(

The 7.3 is the last of the old school international tractor engines.
They will run forever. They will run as good at 400k as they will at 5k.

A 5.9 B is better at either interval in both power and fuel economy, but the 7.3 comes in a much better box.
 
i just drove my 01 7.3 890 miles one way should be driving it again this weekend pulled a trailer with about 1200lbs of equipment on it. i averaged 75 mph the whole way and got 14-15 mpg
 
Jody Treadway said:
I DD a early 99 7.3, auto, 4x4 ECLB with 3.73s and 265 LT tars. Bone stock keeping it under 65 on the highway, I got 18 regularly. But if I drive it over 70, it falls to around 15-16.
Now it has an AFE CAI and an Edge programmer on a "tow" tune and I get similar MPG. Towing my Ranger to Windrock, The Flats, etc, I get 10-11.
These are all hand calculated BTW.
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i am also DDing a early 99 7.3, mine is a 6 speed, crew cab, lb, 3.73's and 285's tires, 4" down pipe, 4" straight exhaust, napa 6637 filter, i am getting 18-20mpg on the highway with economy setting on Ts performance chip, havent towed much with it yet, mine is also hand calculated

this is my third 7.3 truck, and everyone of them got different mpg

my 1997 7.3 crew cab long bed, auto, 6" lift on 35's, 3.73's, ts performance chip, mbrp exhaust, napa 6637 big filter, upgraded wicked wheel, upgraded injectors, got 14-17 mpg on the highway and 10-13 Towing

my 1996 7.3 crew cab long bed, auto, 4.10's, stock height, stock tires, 4" exhaust, tymar intake, got 12-14 mpg on the highway and 10 towing
 
Okay! I picked up a new IPR, EBP/pipe today and replaced both. The IPR was gummed up bad so I replaced with the new one and will keep the old one as a spare after I clean it good. The EBP was shot! Completely stopped up. The EBP pipe was rotten and stopped up! I think I helped it! It runs even better now. I will check my mileage on the way to NMB on Friday.

ai418.photobucket.com_albums_pp266_xjtrailrider_IMG_20140723_213032_464.jpg
 
What are you calling an IPR and EBP?
 
Jeff B said:
What are you calling an IPR and EBP?
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Injection Pressure Regulator, mounted on the HPOP on the drivers side. Exhaust Back-pressure Valve, mounted above the water pump and attached to a tube that runs back to the exhaust manifold on the pass side.
 
Those tubes are pretty famous for crapping out. Once you get all the bugs worked out, those motors will run fairly well. I just never was crazy about the way their injection system works....seems like a difficult way to accomplish something fairly simple. Too many sensors, oil pumps, O-rings, etc....but, it works.
 
This truck runs awesome now! After three tanks of fuel since the fix I'm getting 17.5 for a three tank average. I have plenty of reserve power and accelerations is great, it will set you back into the seat! No tuners or chips, just a RiffRaff filter kit and thats it. I might do exhaust next and call it done.
 
xjtrailrider said:
This truck runs awesome now! After three tanks of fuel since the fix I'm getting 17.5 for a three tank average. I have plenty of reserve power and accelerations is great, it will set you back into the seat! No tuners or chips, just a RiffRaff filter kit and thats it. I might do exhaust next and call it done.
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The IPR is simply a relief, if there was a malfunction there you would surely know it.

Do you think the tube replacement gave you the desired results in mileage?
 
It will Definitely set a code prior to loss of power and mileage from my experience. It will undoubtedly cause a hard start hot if leaking only a small amount. It is however more than a relief valve, it's the sole item controlling high pressure oil in these trucks. The tube could have been busted, causing an exhaust leak and cause all the symptoms.
 
mysterync said:
It will Definitely set a code prior to loss of power and mileage from my experience. It will undoubtedly cause a hard start hot if leaking only a small amount. It is however more than a relief valve, it's the sole item controlling high pressure oil in these trucks. The tube could have been busted, causing an exhaust leak and cause all the symptoms.
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what else does it do other than relieve pressure?

if it's leaking, it's causing a low pump pressure therefor the injectors do not spray correctly? Causing poor mileage & power?

I will check the tube on my psd, may have this issue too.
 
Jeff B said:
what else does it do other than relieve pressure?

if it's leaking, it's causing a low pump pressure therefor the injectors do not spray correctly? Causing poor mileage & power?

I will check the tube on my psd, may have this issue too.
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Just any other regulator works basically. The ecm monitors icp pressures and calculates desired values based on the values of items apps, calculated load, boost etc, it then opens and closes the valve to keep pressures at the desired level. Closed or stopped up and the pressure can continue to build until the 4k relief valve in the pump pops open, IPR open allows oil to exit back into sump. It's pwm with a ground control and constant 12v. Seriously seriously doubt that was the issue with the truck mentioned in this thread but anything is possible. I vote the ebp tube was leaking/broken cause an exhaust leak. Loss of exhaust back pressure itself can cause the issue or a clogged tube may cause abnormal wastegate and warm up valve function. Most of this is caught in a basic diagnostic hour in any shop.
 
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