my 1999 e350 7.3 is mysteriously losing about 6 quarts of oil between oil changes. i also noticed lately that it stinks like burnt oil and idles rougher than usual. i have a hunch that my injector cups/o rings are leaking. i dont see any oil on the ground. i have a local diesel shop that i trust and they agreed with my theory from what i explained, however he said to use only motorcraft injectors if i do a full replacement. if i go down this road and spend this money, id like to put bigger injectors in so i can get the most out of a hydra tune. this brings me to a few questions:

are these stock injectors single shot or double shot?
if i step up the injectors, what set should i get? or am i rolling the dice with aftermarket stuff?
do you think 204k miles is too much to start messing with injectors? pyro meter will be utilized.

thanks for the help!

 

General consensus is that 160/0 or 160/30 injectors are a great upgrades for a mostly stock motor. Shouldn't have to worry about blowing anything up with that size injectors. The injectors in your truck are split shots while the two above are single. Also an upgraded compressor wheel for your turbo would be a good idea. There are some really great injector rebuilders that offer those sizes of injector. Bitterroot Diesel also offers brand new upgraded injectors.

 

You are likely right and your injector o-rings need to be replaced. Alliant is the OEM manufacturer for injectors and they can be purchased new as AD (140/0) split shots or AC (160/0) single shots. With the single shots or "bigger" injectors, you will need tuning. If you are getting tuning, you will need at a minimum a pyrometer (as you indicated).

It is a very slippery slope that we refer to as PMS (PowerStroke Modification Syndrom) around here.

The ONLY two places I would even consider recommending a friend to for remanufactured injectors are @Bitterroot Diesel or @DZL JIM (Rosewood). They are by far the best and most reputable in the game.

Bitterroot Diesel: https://bitterrootdiesel.com/

Rosewood Diesel: https://www.rosewooddieselshop.com/

Both of these shops are site sponsors and great people to work with.

If you decide to go with new AD's, I believe both of these shops can help you out, but if not, then Clay at @Riffraff Performance is another site sponsor that can get you hooked up with new Alliant injectors.

Riffraff Diesel: https://www.riffraffdiesel.com/99-03-super-duty-7-3l/

If you have the time for the truck to be down, then wait and pressure test the cups when the injectors are out instead of buying everything up front. Cups are not a maintenance item, they are a replace as needed item. So, changing cups because you are in there is not frowned upon, but it is also not recommended either. Unless you like the new shiny stainless steel cups from Riffraff, then go for it.

A prominent member on here had his o-rings go out on his low mileage 7.3L, it happens. Most last near 250,000 and other have gotten up to 500,000 without issue. Just the luck of the draw. 204,000 miles is NOT too much to be messing with injectors, but as PMS will be diagnosed soon I am sure, when going up injector sizes, there is a point when the supporting equipment needs to be looked at as well. For example, turbo, intake, transmission, etc... You could go up to a 160/0 or 160/30 with minimal PMS flare-ups, but much past that you need to break out the credit card.

@KC Turbos is a good choice for drop in turbo upgrades. Although, most of his products can be purchased at the other diesel shops mentioned above as well.

KC Turbos: https://kcturbos.com/

I hope this helps!

 

Also if your van has been properly maintained and not abused then the motor should still be pretty fresh at 204k miles. Definitely not to late to upgrade injectors.

 

Leaky injector o rings often show themselves with a contaminated fuel filter. Easy to check for a black fuel filter to confirm diagnosis.

And since you are smelling it another possible cause is worn turbo seals. That allows oil to ooze thru to the exhaust side of the turbo where it burns.

So you have good reasons to give your wife why you really should spend the vacation fund on some go-fast goodies.

 

If you don't have fuel in your coolant I would not mess with the injector cups.

If you have black oil in your filter housing it's injector orings, but I have seen leaky orings on a 7.3 that did not have oil in the fuel bowl.

I have also seen injectors fail internally and cause excessive oil useage.

If you are keeping the van then spend the extra and get new Aliant Injectors.

I have had great experiences with RiffRaff and BitterRoot.

 

Pull your fuel filter, does it look like this?

Black instead of light tan

​​​​​​Has your mileage gone up in the same timeframe as your oil consumption? If so it points to injectors. If not it could just be the turbo oil seal leaking

 

If it were mine I’d suspect the injector o-rings. Depending on whether you are paying a shop to do this and how much time and money you have to spend on it, you could either re-ring the originals and hope it fixes it or you could get a little proactive and put new ones in. If you don’t want to mess with tuning you can get some AD/30’s or stock AD (140/0) split shots from Bitteroot or Rosewood fairly reasonably.

How long do run the oil to lose the 6 quarts?