OE-remanufactured AD-code HEUI injector — the standard injector for cylinders 1 through 7 on 1999.5–2003 Super Dutys. Alliant Power replaces the wear components and end-of-line tests every unit, so you get matched flow across the set without paying new-unit money. Cylinder 8 takes the AE long-lead; we stock that too.
| Part number | AP63903AD |
| Brand | Alliant Power (OE remanufactured) |
| Condition | Remanufactured — torn down, wear components replaced, end-of-line tested |
| Application | 1999.5–2003 Ford 7.3L Powerstroke — standard AD injector, cylinders 1–7 |
| Warranty | Alliant Power factory warranty on this unit. On anything we remanufacture in house: 1 year, 30 days on electrical components |
| Core charge | Refundable $100.00, refunded in full when we receive your rebuildable core |
Fits / Applications
- 1999.5–2003 Ford F-250/F-350/F-450/F-550 Super Duty 7.3L Powerstroke
- Excursion 7.3L — pairs with one AE long-lead in cylinder 8 on these trucks
- Navistar T444E applications calling for the AD code
Cross Reference: Part Numbers This Covers
AP63903AD · 5C3Z-9VE527-BRM · CM-8R-RM · F81Z-9E527-CRM · CMR-8-RM
Reman or New?
Both fit the same trucks. A remanufactured unit is rebuilt to the original specification and end-of-line tested, and it saves you real money per hole — which adds up fast when you are doing all eight. A new unit has zero hours on it and no rebuild history, which some owners prefer on a truck they plan to keep forever. We stock both and will tell you honestly which one makes sense for your situation. Prefer new? See the new AP63803AD version.
Why do I see this injector cheaper online?
Short answer: it is usually not the same part — and on a 7.3L you pay for that twice in labor. Read why ↓
Search any OE number and eBay, Amazon and a dozen storefronts will show it well under dealer cost, sold by outfits with no name, no address and no phone number. We lose business to those listings every week — and we see a lot of them come back through our shop. Here is what is actually different.
- The part number proves nothing on its own. Counterfeit injectors and pumps are stamped with the same OE numbers as the real thing, in housings cast to look identical. The number in the listing title tells you what the seller claims it is, not what came off an OE line.
- “Remanufactured” is not a regulated word. A genuine reman unit is stripped to bare components, has its wear parts replaced — nozzle, plunger and barrel, solenoid, seals — and is then run on a calibration bench until it meets the original flow and response spec. A cheap one is very often cleaned, resealed, painted and shipped. Both get called remanufactured.
- No full teardown, so no idea what is worn. A proper rebuild means the unit comes apart completely and every part gets inspected and measured against spec — not just the ones that are obviously bad. Skip the teardown and you are reusing worn internals inside a freshly painted housing. It will run on the truck. It will not last.
- No factory-spec bench load testing. A unit is not finished until it has been run under load on a test bench and made its numbers across the range, not just at one easy point. That bench time is most of what you are paying for. Sellers working on price cut it first, because nobody can see it in a photo.
- The warranty has to be honored by someone. Everything we remanufacture in house carries a one-year warranty, with 30 days on electrical components. Parts we supply as an authorized dealer carry the manufacturer’s own warranty. Either way you call us, a real shop in California, and we sort it out. A marketplace warranty usually means shipping the part overseas at your own cost and hoping for a reply.
- No core program. We credit your rebuildable core back in full. Discount sellers generally will not take one, so the gap narrows the moment you account for the core you are now stuck holding.
- The part is the cheap part of this job. On a 7.3L you are pulling valve covers and working under the oil rail. On a 6.7L the cab may have to come off. Doing that labor twice because one bargain injector failed costs far more than the difference you saved on all eight — and a failing injector can wash a cylinder or put debris through the fuel system on its way out.
We are an authorized dealer and a working fuel-injection shop — we have been rebuilding and testing this hardware in Woodland since 1993, and the people who answer the phone are the people who run the benches. Not sure this is the right part for your engine? Call us with your serial number before you order and we will confirm it. Send your rebuildable core back and the core charge is refunded. And if a price somewhere else looks too good, call 530-668-0818 and we will tell you straight whether it is a deal or a problem.
Why Buy From Valley Fuel Injection
We are a diesel fuel-injection and turbocharger shop in Woodland, CA — rebuilding pumps, injectors and turbos on our own benches since 1993, not a drop-ship storefront. When you call, you talk to the people who test these units. Not sure which version your engine takes? Call us with your engine serial number before you order and we will confirm it — that check is free and takes a couple of minutes.
Not sure the injectors are the problem? We flow-test and diagnose 7.3L injector complaints in-house — see our injector testing service before you buy eight of anything.
Ready to order online and ships free ground in the lower 48 states. A refundable $100.00 core deposit is added at checkout and refunded in full when we receive your rebuildable core. Questions on fitment? Call 530-668-0818.
Pricing covers the unit itself. Any applicable sales tax and the refundable core charge are additional; ground shipping in the lower 48 is free. Buying tax-exempt? Qualifying diesel repair shops, fleets, farms, and agricultural operations can purchase tax-free. Set up tax-exempt purchasing once and every qualifying order is tax-free going forward.







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