So it turns out my IDM is bad and it's the usual culprits. Looks like some SOT-223 pre-drivers on the top and some 0805 SMT resistors on the back. Changing them is easy and probably readily available on Digi-Key, if I knew what devices they were. There are a few people on You-Tube doing similar repairs but nobody shows a parts list or schematic.

I'm starting to get grief from the wife on how much I'm sinking into this truck and still have far to go and trying to avoid another $300 thrown down the hole.

Anyone familiar with these parts, exactly what part number they are....or possibly a schematic?

Thanks

 

https://www.dieseltechchatt.com/ Quite a few folks have had good luck with these guys.

 

Yesterday I sent them an email about a list of parts, or possibly selling me a "kit", but no reply yet.
I doubt they will be interested

Thanks'

 

Unfortunately nobody is sharing what those components are but I took a chance on buying one for $80 on Facebook marketplace. My original unit was F7TF-128\B500-AB (IDM-110) and the replacement was XC3F-12B599-AC (IDM-220) from a 2003 F350. 1992-1996)
I have a 1997 250 HD and it's a little confusing because sometimes it's included in the Gen 9 category (1992-1996) and other times it's included in gen 10 (1997-2003).

Regardless the IDM works great and starts up in 1/2 the time as the older IDM. I did a little reverse engineering and it looks like the area below which is a common failure point is not the injector drivers but pre-drivers for the switched 110v power to the left and right banks. Seeing the damage and DTCs from the early buzz tests make sense now and there are clues you can check for to find out if these areas on the board are starting to fail.

If codes are thrown during the buzz test, you should isolate the 4 injector banks and plug in only 1 at a time. You should only hear 2 firm and distinct "clicks" from the 2 cylinders that are being activated throughout the entire 8 cylinder activation cycles.You should not hear any faint clicks as the buzz test is firing the other cylinders that are unplugged.If you hear more than 2 clicks, or 2 firm clicks and more faint clicks, the area shown below are damaged are are starting to fail.

This could cause cylinders to receive partial fuel when they're not at the compression cycle or any other strange things to happen. I have a suspicion the previous owner ran the tuner at the max setting for too long which stretches out the injector pulse causing overheating of these drivers till they cooked.

That's just my 2 cents and time to move on to other things now and this is getting fully restored.

 

Glad you got it figured out. Some say the newer IDM is an update on these old gals. Cleatus, who is on this forum, says that they are all the same. (11o v-120v) The IDM from any year 7.3 will work with any year 7.3 engine.

 

The "raw" PCB has a different rev number but they look identical as far as I could tell but who knows about the component values.
On a side note, the "new" IDM must have been sitting for years outside. The vent hole in the back was wide open and didn't have that little check valve or filter on it.

When I took the lid off, the entire board and inside the case was coated in white dust and chunks like barnacles on a boat. I dumped out a pile of that crap. I was sure it was shot, but I soaked the PCB in cleaner and it freaking looked like brand new. Whatever FORD used for that gummy coating on the board worked great and protected everything through the years.

Thanks, I'm pretty happy

 

All IDMs work
the 140 IDM will make the injector open sooner and give you a tiny bit more power if running on a lower volt IDM or your armature clearance is a bit too close from worn poppets
Some say easier starts and better cold idle

I need to try this mod out

 

Well, not JUST me, but I did stay 5 nights at a Holiday Inn Express about a month ago.

Scopes don't lie - From the 100A, IDM-100, IDM-110, to the IDM-120 they all put out the same voltage and are all interchangeable. However, the circuitry is much better in the newer (higher revision) ones and at this point the newest "100" is 30 years old. It's usually never a bad move to just find an IDM-120 (unless it's been underwater or has 500K miles) and shove it in your older pickup.