Okay, so I am a newbie! I have a 2002 7.3L Turbo Diesel and have recently had a reduction in MPG. I have not as yet done any modificaitons (70K miles) but was thinking about cutting out muffler, going to straight pipes and adding a K&N Generation II FIPK 57-2530. I am happy with the performance of my truck but would like to improve the performance and MPG. I love my truck and am looking to do mods that will not cause long term damage to engine (I would like to drive this baby for about 400K).

Any input / advice would be greatly appreciated. PS - if it matters I am in a hot / humid climate (Central Florida) and do most driving not under load.

 

Before you do power mods, you should consider fixing a couple of known 7.3L problems - most notably (and this is what I found about mine), the fuel system.

It seems that Ford wanted a feature that would help sell the Superduty, so they added an intercooler. This cost them a bunch of money, so they cut costs elsewhere. Prior to 1999, the Powerstroke had a regulated fuel return from the fuel rails. This allowed any air in the system to be sent back to the tank. When Ford added the intercooler, they removed the regulated fuel return and left the engine with blind fuel rails - any air in the system MUST now be injected.

In addition, there are known problems with the fuel pickup in the tank that commonly sucks air into the fuel and sends it along to the engine - to be injected.

The problems this causes, and the fixes, are well documented in numerous threads on this forum and in research papers posted on another web page that this overzealous forum protection software will not allow me to name. It is not that it won't allow a link - it won't even allow me to post the name of the website. Send me a pm, and I'll get the name to you.

Air in the fuel results in noisy injectors, causing the infamous diesel 'cackle', reduced power, reduced fuel mileage, more smoke (but not from excess fuel and high power, but from incorrect injector timing), and eventual damage to the injectors.

Check it out - especially if you have noticed a drop in fuel mileage. After much research, I decided to make sure mine runs as it should run before I spend money on performance mods. I have done the fuel tank mod (excellent improvement - and cheap, too). When I bought my truck, it got 16 to 17mpg. Over a few months is gradually dropped to 13 to 14. The first tank of fuel after the fuel tank mod got 17.2mpg.

I just ordered a shift kit and spin-on, external filter for the trans. Next will be a regulated fuel return, followed by trans temp, pyrometer, and boost gauges - THEN, I'll start modding it with trick performance goodies.

 

The web site is texas-town-car. Add triple w in front, take out the hyphens, and add a com to the end. Much of the same info can be found in numerous threads on this forum, but most of those threads refer back to the above listed website. Back then, you could post a URL address, but it wouldn't link. Now nanny-software won't even allow you to post the name of the website.

 

Could You Tell Me How To Perform The Fuel System Modification Or Tell Me A Site To Go To. Because I Have 2003 7.3 F250 Fx4 And My Milage Dropped From 17 Mpg To 13 Mpg. I Just Went From 265/75/16 To 285/75/16 Bfg Allterrains When I Noticed The Milage Drop. It Might Be My Tires I Am Just Curious If Its The Fuel System.

 

Did you take the tire diameter difference into account with your fuel mileage calc? Remember that there is about a 7 % difference in diameter from the 265 to 285 tires. That would change your 13 to almost 14mpg. Plus, there would be expected to be some loss in fuel mileage with the larger tires (more rolling friction, etc).

Still, a 3mpg drop is too much for just the tires. Did you have a front end alignment done? What tire pressure are you running? These will make a substantial difference.

As to the fuel tank mod, there are several things on the fuel pickup that need to be addressed. It has been explained much better by others than I can do - I've only done it once, and with a purchased kit.

But, the kit I got eliminates the mixer and replaces a coupler with one that is designed to seal against suction - unlike the OEM Ford coupler. Because it eliminates the mixer, it also moves the fuel return pipe farther away from the fuel pickup.

Run a search on this forum for the fuel pickup mod. You'll get some much better explanations than I am capable of supplying.

 

Okay. I found out why links aren't permitted - they aren't allowed for users with less than 25 posts so as to reduce the spammers. Works for me.