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E99 7.3L Injector question

7725 Views 5 Replies 3 Participants Last post by  losfinch
I have what I believe to be an E99 7.3.(VIN tag photo attached)Block serial number 667242. Bought it about a year ago 293k miles on it and after finally repairing some "oil in coolant" problems I am mentally ready to take on getting it running smooth. I just finished compression testing it this weekend and all 8 cylinders are at or very near 360psi so I feel comfortable moving forward without a complete rebuild(couldn't afford that anyway). I noticed that 7 injectors looked original (very dark brown tops) with "AB" on them and one newer, Cylinder #4,(cream colored top)"AD". I thought the E99 had "AB" injectors?
I do not want to add any tuners or special programs. So here's the million dollar question: Can I replace them all with "AD" without any special tunes?
Can I can ship them off for rebuilding even though one is different.
Will a rebuild shop accept 7 AB's and 1 AD for 8 of the same types as cores if I buy already manufactured injectors?
Who is the best shop to use for rebuilds? AND lastly will shops do 4 at a time? I'm on a limited budget.


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Looks like at some point after leaving the dealer someone replaced the early 99 AB injector with one of the "cackle cure" AD injectors that I think Ford was replacing for people to help try some of the cackle noise coming from the fuel starved back driver's injector. Mine is 3/98 build and still has all 8 AB injectors in it. I'm the second owner and apparently the previous owner didn't take it in for the replacement (which I'm more than ok with).

Lots of good shops/vendors out there to talk to about your injector needs, especially if your looking to keep things pretty close to stock with no special tuning. KT, Dp Tuners, Full Force, Swamps, etc. You can even get new Alliant ones for a pretty decent prices. Lots of options and different opinions but since you are wanting to pretty much stick to stock without any new tunes and such your choices will narrow down a lot quicker.
Can AB and AD exist together? Can I go all AD without a special tune?
The AD was the standard injector for '99.5 7.3L's. In 2000, Ford started putting an AE injector in #8 for the cackle fix (that didn't really work). That being said, the code on the injector solenoid doesn't really mean the injector matches that code. An injector rebuilder may have stuck an AD solenoid on an AD injector body.
If you had 7 AB's and one AD, you'd get a cylinder contribution fault when running a cylinder contribution test. IIRC, the AB's had a capacity of 99cc's and the AD's 115cc's.
You could run AD's in your truck without any programming changes. You'd get a bit more power out of it. AB and AD injectors are both split shot. If you went with single shot injectors, that most rebuilders sell as higher performance units, you'd need a program.
Thanks for the information. It looks like I can go with all AD's since they are split shots like the AB's. Now I just need to save some money and see if any injector sellers/re-builders will accept AB's as cores for AD's. Thanks again
Good info there KLHansen :)
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