What year did the 7.3L injectors get a pilot injection to quiet down the engine? I have a 2000 and am wondering if I have the latest and greatest. Any other changes after 2000 that improved fuel economy or power?

 

The number 8 injector is the long lead. I beleive it was a factory deal where they replaced all #8's with it.

To my knowledge it didn't make a huge difference.. no huge fuel economy changes.. other than your right foot

 

What do you mean "#8" and "long lead"? Cylinder #8? Why wouldn't all the injectors be the same?

 

Ford put the "Long Lead" in number 8 to try and cut down on "cackle".

On the pilot shot or split shot injectors they are standard equipment, but most people upgrade back to single shots because they are more efficient.

 

Firing order and the design of the fuel rail.

 

Split shots first came out in 97 in certain California trucks. From 99-03, all 7.3L's had split shot injectors.

Are split shots the latest and greatest? No. The most common injector upgrade is to swap them out for single shots. Split shots use more fuel, especially at idle, and require higher oil pressures to run correctly. They were simply added to reduce emissions.

As for the long-lead injector, it was added because Ford designed the fuel rail to deadend on the driver's side #8 cylinder. On top of that, the #6 injector (which is right next to the #8) fires immediately before the #8, so that injector typically is starved for fuel. Ford's band-aid fix was to add a long lead injector, which fires a larger pilot shot, to try and fix the problem. A correct solution would have been to not dead end the fuel rail right there. So us regular folks modify our trucks to add a regulated return fuel system, which removes the dead end at the fuel rail, and eliminates the need for the long lead injector.

 

To add to Curtis' post, not ALL of the trucks have the LL. You can hear it if you ever heard one without it vs. one with it. Sounds like someone tapping on the block with a ball pein hammer every time it fires! I would've replaced mine a long time ago if I didn't already have plans to drop in bigger injectors (singles or hybrids -- haven't fully decided yet). You can also put in the DFA Cross-Connect-Kit (what I have) for substantially less than the full RR systems out there. It fixes the dead-head problem just as well. And you can upgrade the CCK to a RR later if you want to. I have the RR parts ready to go in, but I'm waiting on my fuel pressure gauge to go on first (also on the way). I want to see where I'm at now.

If you just want to quiet it down, do the in-tank mods, HPX (high-pressure oil cross-connect), install the RR or CCK, and run syn oil. Then you'll likely hear that pesky LL #8 if you have it. Then you can put a regular injector in there and have a fairly quiet 7.3.

 

Thanks for taking time to reply. Very informative. Searching the site for more information on these items will keep me busy for a few days.

 

so if i get some ss does it have the long lead you guys are talking about?

 

The father of the HEUI injectors sits just a few offices down from me at work. I had a 5 minute chat with him and here is what he explained to me. (Mind you, it has been many years since he worked on the project AND I'm giving you this information second hand so correct me if I'm wrong.) All the injectors in a set are the same. A bar code is placed on each injector that allows Ford to set the "E" trim (electronic) in the engine ECM. This accounts for manufacturing tolerances and balances fuel flow across the set of injectors. Then there is an additional "P" trim (position) that is programmed to account for the position in the fuel system.

Is P trim the "long lead" that you are talking about? If you add a fuel rail balance kit then you will still have the P trim programmed. How do you change the P trim after you've made these modifications?

Also, if you change injectors at home how do you get the proper E trim programmed for each of the new injectors?

 

OK, So, AA injectors are single shot right?

A friend of mine wants to go back to them 'cause his old (Cant remember yr) truck got MUCH better fuel mileage. I am still pretty new the SD scene, but with just over 100K on the truck, I probably should be thinking about injectors and start saving. Unfortunaltey for me, mileage is a bigger concern than power (375 mile round trip to work) I of course want big power and mileage, but hey, dont we all?

 

There are tunes made for fuel economy that add power. I have the DP tuner 80hp econ program on my tuner. It ususally stays there or 120 race.

 

This might have already been said, but the engineer I talked to said that single shots do get better mileage because you can inject fuel quicker and have more possibilities with timing. It would require a custom tune to take advantage. There will more more combustion noise.

 

Joe is certainly right about how noisey it is if there is not an AE LL injector in #8. My Early 99 came with 8 AB codes. #8 quieted way down after intalling the CCK.

 

There is no programming for the LL injector. It's just a physical difference in the injector itself that causes the longer pilot shot.

Most injectors can be tuned to get the same mileage as stock injectors. If your friend is losing mileage like that, more than likely it's in the tuning.... or his right foot.