DDEC2 problems...missing and falling over iteself for 15 seconds.

Hey, looks like a load of info on this site so I appreciate any help I can get.

So I have a 93 kenworth t800 with a 12.7 ddec2 60 series detroit. Ole girl has been a great truck and engine...until last Wednesday.

I had just replaces some brake shoes and other repairs on my tag axle. When I got done I fired the truck up to make sure there was no air leaks or anything.

Turned the key and it started but was missing and falling over its self for about 15 seconds then it leveled out and came to a nice high idle. I just thought maybe it was just a fluke or something.

I started it again later, and it was running very rough again and kept missing and bucking and acting crazy.

So long story short its totally non drivable now. I have lost thousands of dollars in missed hauls, and I'm desperate for any info because it seems like the ddec2 has absolutely zero info online.

I have checked the fuel system, checked for bad grounds. And checked the batteries. Weird thing is when you turn the key to the on position the check engine light and stop engine light come on for just a few seconds then go off (like they should if I'm not mistaken) but once it goes to its warm up high idle stage, it will run for a minute or so, then randomly the 2 lights will flicker and it misses and acts crazy. Almost as if you turned the key off then instantly back on and the high idle cycle starts all over. Because if left running for 10 minutes or so it will never exit the high idle mode.


I just joined today, so I'm new to this whole forum thing. So if there is any suggestions in editing, or forum etiquette that I am unaware of please let me know, thanks and I welcome any suggestions to get this money pit back on the road.

 

Well here's the problem, it's a 93 truck, with an 01 cab, checked it all with the dmv before I bought the truck, I guess something happened to the cab and they replaced it. With that they did a crap job of hooking everything back up, so the data link has 1 wire running to it. Last few trucks I have had I used the cruise control to check codes, but this one has the same problem, cruise control hasn't worked since I bought it. So it doesn't let me pull flash codes that way. I read somewhere today that you use the engine override switch to pull codes not sure if that's true, but if it is, then same problem, nothing is wired to the switch

 

However I also thing it's a power/ground problem to the ecm. Because its like the ecm is losing power constantly. But j don't know which wire is the power/ground

 

Ok, I'm going to go work on it tomorrow morning, I'll check out all the ideas and see what I can find, thanks!

 

On those 2 fuses in the battery box. One tested good. The other one, I pulled the fuse out and i have 12v on one leg. And 9.8v on the other, shouldn't that be 0v? Otherwise that defeats the purpose of a fuse wouldn't it?