Hello all,

I am looking for a way to improve my wife's, F250 Crew Cab 7.3L PSD, MPG. currently with the work I have done she gets 16-17 city, and 20-21 Highway. My friends and other gear heads were impressed with this, and said I would have a hard time squeezing out more efficiency. One recommended a programmer module. I have no knowledge of programmers, and had two questions:

1. Can I increase her mileage to the uper 20's with a programmer without damaging the engine?

2. What do I look for in a programmer, and which ones would you recommend?

-Vycan

 

You're kidding right?



If its seeing 20-21mpg you're already at the top of the mpg spectrum. Very few trucks see anything that good. The only things that might help would be 3.08 gears and/or a gear vendor unit. Unless you're putting alot of miles on each year its going to take a long time to recoup the cost. The gear vendors is about $3000. Programmers probably aren't going to help you much with what you've got now, and may actually take it down. My advice, its doing spectacular for a PSD, leave it alone.


FYI, you stated "currently with the work I have done" you MIGHT consider posting what "work" you have done to it. That can greatly affect the answers.

 

Only 21 MPG out of a 3/4 ton 4 door truck eh? That blows.

 

Come on, 21 mpg... that's insane... especially with that ULSD fuel... makes me wanna buy an older turbodiesel.

But since your wife drives it... that's insane... then again, my mom will drive a stick over an automatic any day of the week. She's trying to get my dad to get a F250 with the 6 speed... she hates automatic. My Dad on the other hand wants an older F150, '97-'03 Old body style with the supercab and 5.4... but you can only get it in an automatic.. and my Mom doesn't want automatics... so... they are shuffeling between a F250 and a F150 with the 5 speed 4.6l v8 supercab old body style... I'd rather see them get the 6 speed on the v10 or diesel...

 

Yeah i am getting at least 31 towing.

I've that checked out.

 

No no, really I'm serious, one of my buddies is a major gear head and does all sorts of stuff with his vehicles for racing, and he said it is possible. I wasn't so sure, and figured I would ask about it here. I have no knowledge about programmers, so would not know if it is possible or not. As far as how her truck gets the mileage:

1. Engine oil change every 3,000 miles with angine restore additive.
2. Lucas fuel injector treatment every oil change.
3. Annual transmission filter change.
4. Annual fuel filter and air filter change.
5. Larger capacity intake with large conical freightliner filter like those used on semi trucks, have not built a cold air isolation box around it yet.
6. MOST IMPORTANTLY: Keep RPMS under 2k at all times with a preferrance for 1700 or less. This means top highway speed is about 63-65mph.

So, what you are all joking about is that her truck is already maxed out on efficiency, and a programmer won't help?

-Vycan

 

Plain and simple... 21 mpg is DAMN GOOD for that truck. There are guys out there with newer 7.3s that are 6 speeds, lowered, 3.08 gears, and mileage mods (including modifying body lines for less air resistance) that are only getting like 23-24 MPG.

 

Ok, lets figure out a few things here. How EXACTLY are you calculating the fuel mileage on the truck? There is only 1 way to do it correctly, and if not done that way will inflate your numbers.

You run that oil restore junk in the oil? You do realize that the engine oil is used to drive the injectors and is very susceptable to addatives. Alot tend to "gum" up the oil which is a death sentence for these engines. This isn't an old IDI truck that can run that stuff, its a HEUI system. Apples and oranges. If you want to run an addative get the antifoaming addative from your local Navistar dealer. That will actually help things and is made specifically for the HEUI system.

Your friend that says higher is possible is technically right, as 1 or 2 more mpg might be squeezed out, but it won't be cheap to get it there. Let me guess, your "gearhead" friend throws a programmer on a truck and then watches the overhead console compute the mileage. Whenever you put a chip or programmer on it alters the fuel map and makes the consoles read insanely high (30mpg +).

You do know that the fuel filter change interval is every 15k, not a timed event. Unless you're buying your fuel from a high volume station (ie truck stop) I would go to every 10k or less. The little out of the way stations don't tend to move much diesel and it goes stagnant in the tanks, as well as take on water.

Hopefully for your air filter you didn't use a K&N filter. If so then............well you might just get the chance to break in a brand new crate engine.

Changing the trans filter every year is useless. Its nothing more than a screen that catches large pieces. You're just wasting money there. Though dropping the pan to inspect it has its own benefit. You'd be much better off with a trans filter kit from www.dieselsite.com. Bob has a very good kit and this actually filters for small particles, so the trans is protected.


As stated many times, if you truely are getting 21mpg on the road then LEAVE IT ALONE!!!!! Maybe 1 in 20 PSD trucks actually get that kind of mileage on a regular basis. Though I'd really like to know how you're calculating it as most people don't know how and THINK they're getting great mpg. You already have the most important thing, you know to keep the rpms under 2k. Thats the biggest key to mileage.

 

So would putting a quart of lucas in a diesel engine hurt it?

 

Depends on the engine. In a Cummins for example I wouldn't think twice. Its only being used to lube the engine. On a truck with a HEUI injection system (PSD and Caterpillars) I wouldn't as the oil travels through many small passages inside the injector itself. Thats also why using a good high quality filter (Fleetguard) and oil (15W40 oil with the correct CPI rating) along with regular change intervals is even more critical for a PSD.

 

So I shouldn't run a quart of lucas in my 99 7.3

 

Thanks for the input Powerstroke... I didn't even think about the effect of the additive on the HEUI system!!! You may have just saved her truck.

To measure the MPG, I fill the tank up to the same spot every refill. I fill her up until I see the diesel at the same point on the filler neck. Then record the miles driven on the trip. Yes, the trip is set for the diameter of the tires, and yes, I have compared the distances measured with programs like google earth and mapquest for accuracy.

I change the trany filter every year, because I enjoy working on the truck, and it is a waste of money to some extent, but it is $13 for the new filter, and as long as I am down there pulling off the trany pan, I might as well swap out the filter with the new fluid.

I have always done it on all vehicles as a yearly thing, b/c I do not drive more than 10k a year.

No No, I use a freightliner filter, not K&N... what's wrong with the K&N though?

 

It sounds like you're doing your mileage checks correctly assuming you're filling until you see liquid diesel and not foam.

You might also consider a diesel conditioner that has a cetane booster and antigel, depending where you live. I run Powerservice through mine every tank. I never use the cetane boost they have, I use the comb cetane and anti gel. I also carry a bottle of 911 with as well. The 911 can actually boost my mpgs 2-3, but its not anything you can really run long term as its too thin.

For mods to the truck you COULD do a regulated return fuel system and the prepump/intank mods. They do have some benefits aside from a possible small mileage boost. They mainly address air ingress into the fuel system, but given the mileage you get your system is one of the rare ones that seals exceptionally well from the factory. By breaking the system open you risk it not sealing as well again.

I'd keep up on the maintenance and run as you normally do and enjoy it. If you want something else to check take a look at your coolant. If you still have green you need to be keeping up with the SCA levels it or else the cooling system cavitates and pits the water jacket walls. Eventually it errodes away enough to eat through into the cylinder (typically #8). Switching to Ford's gold coolant eliminates the need to maintain SCA levels. You may also want to put a coolant filter in there to catch all of the casting sand left over from manufacturing. Dieselsite sells the complete kit for a good price. You wouldn't believe how much sand is in your coolant eating away at the pump.