I dunno much about those years, but you gotta remember that it's a 444CI motor without the fancy injection system that powerstrokes have. If you think of it along the lines of an old 460, then you're completely normal at 10mpg's with a trailer. My 97 w/460 was lucky to get 10 with just a two horse trailer.

 

i get about 10 in my 99. you have a big motor. it likes fuel

 

Just called a buddy of mine with an 86? 6.9 that has the ATS turbo kit on it. He says his best ever was 13MPG. Usually around 11, and his is a bit little smaller than yours. If you figure out any tricks for these dinosaurs, post it up so I can pass it on.

 

Well I looked around these forums for awhile and seen claims from IDI engines of 17-18 and up to 22 if driven nicely. I know that everything on the internet needs to be taken with a grain of salt but I didn't expect to be that bad. My last diesel ( a 99 F350 w/ 7.3PSD) Honestly averaged 17 between country roads and highways. I expected this one to be similiar.

I am not concerned about the towing part since I figured that would be poor. What I didn't expect was unhooking it didn't change my mileage.
thanks

 

From my experience with my 1990 4x4 7.3 diesel reg cab 8ft bed your mileage is on the low side. First of all with the turbo your pump is turned up a which hurts mileage a bit. The next big factor is tires. Depending on what kind you have it will make a big difference in mileage. When I got my truck last fall I had passenger tires on it. I drove from Chicago to Milwaukee hauling 1000lbs in the bed and got 18mpg with the cruise set at 60. I got some larger 265 75 15's with a load range of E which is one hell of a heavy but strong tire and now I can only get 14-15 no matter what I do. The rolling mass is just so much more compared to the old wimpy tires and it hurt my mileage.

The other factor that most people overlook is injectors. Most folks think that as long as a truck is running the injectors are good. Injectors usually go 100k or so and they need to be replaced for OPTIMUM performance and fuel economy. Yes they will last and work for much much longer but not as efficiently when it comes to fuel economy. As fuel goes up they pay for themselves fast if you drive alot. I was lucky enough to have mine already done. Injectors are a wear item that should be replaced to keep optimum fuel economy and power. I put injectors in a lot of diesels primary older diesel Mercedes but in GM's and Fords and it makes a difference, the car or truck will just run better overall. If you have 177k on original injectors I would bet that they are definitely hurting mileage. Hope this will help

 

Between my Dad and I we have had 2 6.9's, and 3 7.3 IDI's and the 6.9's killed the 7.3's in the milage category for sure. Out of the five only the '94 7.3 has a turbo and it does not get great milage with out the hydrogen kit I have on it. I have found that when the pump is tuned right (up) the milage goes up since you don't have to push it as hard to maintain speed. We turned the pump up on every IDI we have and the milage jumped 2-3 mpg, if you keep your foot in them they will use more. My '94 (with 306,000 miles)can obtain over 20mpg with hydrogen and about 14 mpg without it. The 6.9's were both able to get over 20mpg on fuel only( one of these trucks has over 500,000 miles on it at this time). The IDI's are great motors when tuned right with great low-end power! Hydrogen is the best thing I have done for my IDI's, most people are skeptical, but it works for me.

 

I put a 7.3 turbo in my '76 crew cab for just that reason. With the 390fe motor it was getting 9-11mpg, now I get 16+. 11mpg is a little low, depending on your gearing, tires, driving style, ect. you should be getting at least 14. Mine is a high boy 4x4 with over sized tires and I don't drive too nice either. Also, the injector pumps in these trucks are usually only good for 100-150k, same story as the injectors, the truck might seem to run ok, but....:icon_ford:

 

I like to think I drive quite calmly. I have stock tires. I will have my mechanic look at the shape of the injectors and the shape of the turbo to make sure its not going out.

What is the deal with hydrogen? If I can make a kit what is all needed and if I need to buy one who makes a kit for a 7.3 IDI? I am starting to seriously look at this as an option but I have yet to find anything that explains how it works while towing vs. freewheeling.

thanks

 

x2 on the hydrogen.. heard good and bad.

 

The extra power I get out of the Hydrogen was an added bonus I had not counted on, it is substantial. I pull a 40' flat bed with this truck and empty I wiegh 16,000lbs., I can top hills really close to the same speeds as my '08 6.4 and get 9-10 where my 6.4 gets 3-6. The engine runs much smoother with hydrogen too, really shakes without it. I have no complaints, and it has been running on it over a year! I think it all depends on how much hydrogen your generator produces, mine is big and it puts out quite a bit of gas.

 

What makes a legitimate or fake kit?
DIfferent grades of steel?
The issue I have is no legitimate company is behind this. If Ford made a kit I would buy that but since they dont and so many companies seem shady I would like a link to a reputeable company that someone on this forum has dealt with. I have seen the homeade kits and they just look so ... Homeade
thanks,
lucas

 

Take a look at HydrogenHybridcorp,com, they look pretty good, but very expensive. A lot of people are skeptical, so was I, but I just took a chance and it has turned my truck into a fast, pullin, 20 plus mpg truck! I don't blame you for being skeptical.

 

I know you have all heard it about the hydrogen kits doing this and that..but the guy that rebuilt my engine builds huge Hydrogen Generators for big rigs and has told me he would refund any money if it didn't show an (noticable) increase in mileage.

 

look at your injection pump. i have a 7.3L idi and its lifted 6'' and 35'' tires usually get about 15 mpg in the mountains or back roads and 17-18 highway but then everything droped about 4 mpg and my lines on my pump were loose and leaking fuel so you need to check that.

 

I had the fuel filter replaced and that did make a difference. Last tank got me around 13-14. But my mechanic said I was still running stock exhaust which the previous owner said was aftermarket(figure) all he did was remove the cat it looked like and welded a piece in.

Everything I have found points to the fact that after you add the turbo to the IDI system you should increase muffler diameter to at least 4" from turbo back. I will hopefully get that done within the next month and report back.

thanks for the ideas so far.

p.s. My mechanic also said the turbo is in great shape, no blow-by, and my fuel pump is at the right level.

Dozer

 

No IDI's ever had a cat, but they came with a 2/12" exhaust. I put a Banks 3" down pipe and a 31/2" straight on my '94 Factory Turbo and it made a huge diff., my EGT's went way down and I had more power, seems to be a big enough exhaust for mine. You will have to really work the firewall over to get a 4" down pipe in it, I had to really change mine to get a 3" in it. I would go 3" and then up to 31/2" or 4", it will be much easier. Your truck probably already has a 3" down pipe, the factory turbos had a terrible flattened out down pipe that only had about a 1/2" of flow at one point, yours is probably better. Good luck, let me know if I can help you out.