7.3 mystery problems. Can anyone help diagnose???

[OwnerOfTheBigBlueMoneyPit]

I'm FLAT BROKE, and tired of throwing money into this piece of crap of a van, but I need to work, so I need the van!!! If I can get the van going, and business picks up I can trade this thing in for an Isuzu Cab Forward, but for now my only option is to fix what i have.
Can ANYONE shed any light?
1996 E-350 7.3 Diesel
Runs like a brand new van then for no apparent reason, at any time variable (might happen every 5 seconds or every 5 days) it will drop RPMs, and speed reduces. It might just decrease enough that I can resume for a while with no serious results, but not climb a big hill, and then again it might decline so much that I have to pull over and stop.
Once it happens iy sounds like it's running on less cylinders, and the speed varies. When you rev it up it has a serious hesitation. When it's idling even slower it sounds (of course) much worse.
Nothing seems to help. I've tried gradually increasing speed, stomping the gas, shutting it off for a couple seconds, and flooring it and holding it there. (Yeah, not a smart thing to do, but I was mad and you know how that goes.)
If I'm going fast (65, 75, etc) I might can keep it going till it resumes power. If I'm in the city, I'm probably going to have to find a place to pull over. Once stopped the best solution I have found is to just let it idle in park till the RPMs resume back to normal. Then it will run normally, and then again, maybe not.
Rain seems to worsen it. Actually, rain stops it. If it rains for a couple days, I can't start it at all. If it's moist out it's problematic, If it's dry outside it does much better.

Here is what I've tried:

• Fuel injection cleaner in gas (diesel)

• Slick diesel in tank

• water grabber in tank

• fuel filter replaced (yes I filled it with fuel, till it overflowed... to wash away and surface water)

• replaced most of fuses under hood and cleaned the fuse panel beside the engine. It was really nasty. All the smaller fuses were corroded so bad that there was NO PLASTIC LEFT!!! The larger fuses a few had to be pulled in many pieces. they just disentegrated as I touched them. I replaced all i could get out (and till my new mega-box of fuses was empty).

• I tested all the fuses except for a couple on the bottom I couldn't get my little light up tester on.
• Batteries are almost new. I doubt seriously they have anything to do with it, but I haven't checked them thoroughly, however I did charge both of them up with the charger.
• Checked all 3 grounds to the batteries, and they look fine.
• Cleaned engine (really oily)

• Codes came up as computer (IDM) but everyone is telling me it's probably not the computer. And at $1000 for the IDM, plus installation, i'm hoping they are right!!!)

So I have sank so much money into this thing over the last 2 years that I'm at that point where a van payment don't look so bad anymore. I've only had it 2 years, and it has dollared me to death. I'm not sure how long I will stay in this profession, so I don't want to buy a new vehicle just yet.

I don't think it's worth $1000 for a computer for this van. Don't get me wrong, shes a beautiful vehicle, but as my old preacher used to say "Beauty is only skin deep, but sin is through and through!" and as a former beach vehicle, she's eat up with cancer! Any other things I can try???

I can't even FIND the dang computer!!! I can't find a picture of what it looks like either, so I don't know what I'm looking for!

[speeddemon31176]

I hate to tell you this but the code is right. You just described text book indicators of a failing IDM. You can get them for around 200.00 online. I would check out some of the sponsors on here and you will find you can get one that has been modded and will provide crisper throttle response and from what i hear a slight improvement all around. I am guessing the price you got was from the dealer right?!

Oh I don't know where you are from but if you really want to get rid of the van let me know. I will trade you my E-350 14' cube van. it is a 95 with a 351W. It only has 42,000 on it. It does need a paint job though(former Con Ed van). has shelves and all. Ok enough sales pitch.lol

[OwnerOfTheBigBlueMoneyPit]

Thanks! The only way I'd consider a trade is for a cab forward with a flush utility bed with topper. (Similar to the new rescue squad vehicles, only with cab forward design) Its a plumbing van. The cab forwards with utility beds bring top dollar. I kinda gave up on that one. I need lots of access from outside. I'll check the sponsors and see what they have. Can you give me any hints as to what to look for? One one popular website I saw a link to here I couldn't even find computer or IDM listed! I'm wondering if it's called something else.(?)

[speeddemon31176]

Northern Auto Parts: - Reman Ford 7.3L Power Stroke Injector Driver (IDM)

That is just one online place I have found in a matter of a few seconds searching.

[STurbo90]

the pcm and idm are two different units.

the vans were more prone to water damaged idms.

if the fuse box is corroded, even if replacing the fuses, the terminals and wires may still be suspect, the idm is high current, and if the power supply is bad it will defitnately cause issues.

[DaveBey]

What's the DTC stored in memory?

TSB 03-21-15

It sounds like there may be more to it than a faulty IDM. If the fuses were corroded that bad, there may be corrosion elsewhere.

Cheers from Claremore, OK!
Dave

[OwnerOfTheBigBlueMoneyPit]

Originally Posted by DaveBey

What's the DTC stored in memory?

TSB 03-21-15

It sounds like there may be more to it than a faulty IDM. If the fuses were corroded that bad, there may be corrosion elsewhere.

Cheers from Claremore, OK!
Dave

I fear there is. I'm seriously wondering if this thing was a flood vehicle. At best it's a beach vehicle. Its rotted all out. I'm wondering if the fuse block under the hood is supposed to be exposed in the first place. Shouldn't this thing have a plastic cover covering those fuses???

[speeddemon31176]

Yes there should definitely be a cover over the fuse block. You may be right about it being a flood vehicle. A quick way to find out would be to pull the kick panels and look for signs of water lines. I am gonna bet you that your IDM is bad or the pins are so corroded you are losing power/signal between the IDM and the harness. It is the same exact IDM that is used in the trucks. You could get a used one from the junkyard and try it. I would suggest also removing the IDM and cleaning the pins and take a piece of wire and electronics cleaner and thoroughly cleaning the female connections in the harness.