You must have weak compression, bad cylinders, worn out injectors or something. My very heavy 14' box van with six tires, modified engine, php tuner, terrible aero dynamics is getting 13 - 17 mpg. Plus I am always into the pedal with 120 race tune on all the time. I usually can go 550 miles on 40 gallons. Thats 13.75 mpg. Believe me I am into the pedal constantly.
Have you tried spraying water around your intake plenums and watch for tiny bubbles?

 

How can I check to see if the injectors are clogged? I am not happy with the MPGs.

 

How can I check HPOP pressure without spending hundreds on that HPOP specific gauge? That thing is ridiculously expensive. Rather put that money into a new HPOP since my truck has 200k miles.

 

Auto Enginuity is one way. It's an exellent diagnostic tool. A must have IMO. It will monitor just about everything on the 7.3L, pull trouble codes, adjust the speedo for tire size, etc......

Riffraff Diesel: AutoEnginuity Total Ford Enhanced Bundle

 

I change my HPOP oil every time I start my truck. takes about 15 seconds to empty the HPOP. granted, if you want to eliminate another 1/2 qt of dirty oil, its a good idea. but what about the other 2 quarts in the heads?
not that its a total wast of time but I have way to many other things to do.

now back to our regularly scheduled program:

Barney

 

You will need to have them flow tested. That means taking them out and shipping them off.

For now you can try an additive such as DieselKleen or SeaFoam.

 

ok and how much does it cost to have them tested?...assuming I can take them out myself.

Been using Diesel Kleen...love it...plus 2stroke oil....whata difference in made in reducing engine noise.

 

How many miles on them? You would get some return on testing if you needed rebuilt or even purchasing new.

Riffraff Diesel: 7.3L HEUI Injector Flow Testing

 

196,000 miles if my service records are correct.

 

Yupp. Thats about the sweet spot for injectors..

Maybe you should admit defeat and upgrade to stage 1s!

But yes, you can take them out yourself, its not too hard. And like posted above, Riffraff can help you get them tested.

 

Good to know! So they want $255 for testing and minor repairs? Of all 8 injectors?

Riffraff will rebuild my stock injectors for $125? I assume that is $125 for all 8???? (please say yes Mr....) Riffraff Diesel: Stock Rebuilt Injectors

 

For the $255 that is cleaning, testing, and new o rings. They would let you know if they will need rebuilt and you can get options from there.

For the $125 that is 1 rebuilt stock injector.

 

I paid about 300.00 at Seattle Injector. But if you have some miles I would say pay the extra and get reman injectors instead of testing and putting back in old injectors.

 

I will not test those injectors with amount of miles. Had issue with diesel shop that I told NO test and want rebuilt. But they end test then sit until I call to ask how long rebuilt injector would be. 3 days for mistake Then they process say that it will be $80 for test on 3 injectors I told no. They say amator is shot it wouldn't work correct until it warmer.

I wouldn't test it waste $ plus injectors in those are only good for about 150-250K miles until you are really strict maintain then it last longer.

 

Checking your alignment is critical too. Having all of your tires pointing in the same direction is one more small thing that can be done to increase economy.