Injectors...AA, AB, etc...diff?

[Tail_Gunner]

are the AB and AD injectors interchangable without computer issues?

The PCM will be fine. The HPOP capacity may be an issue. The output of the HPOP was increased when they went from AB's to AD's. The AD's require more HPOP volume to run at all out. The early 99 HPOP is refered to as a 15* unit. The 99.5 and later is a higher capacity HPOP and is refered to as a 17*.

could I switch from AD's to AC's without any issues as well?

It'll run, but it'll idle like crap.
Without starting a war about tuners or getting into a long discussion about all the grief I recently went through concerning single shot tuning for single shots in a Superduty, I'll just say I recommend Power Hungry Performance in this situation.

 

[Tail_Gunner]

it'll run but you won't get the performance gain without computer programming at a minimum and your stock HPOP needs to be in good shape.

The HPOP should be able to handle the single shots.

There are generally two reasons for going to singles:
1)Increased performance compared to split shots of comparable size.
2)Split shots require more HPOP volume than single shots do.

If you take two injectors, a split shot and a single shot, both of identicle total delivery capacity. The single shot will require less HPOP to run right. You can talk to Jody, Bean, Bob @Dieselsite or Bill @ PowerHungry and they'll all tell you the same thing.

That's the beauty of AC's. A bunch of more "go" power for no more "oil"
power. The trade off is, you gotta get tuning to get them to run right.

 

[BJS]

TG you are correct and without looking up the fuel delivery specs with a weak pump you may see CEL even from a 17° HPOP in weak condition at WOT even though it was working fine for smaller split injector.