swoop, for me;
"people tend to look at you funny and start walking in the other direction to avoid you",,,
always...
lol

Final report from L1ftmech to L1ftmech on this issue.
New main injector arrived yesterday and engine is now running well.
On to other repairs!

hehe... i talk to myself all the time too... i tend to call it rehearsing what i'm going to say to whomever i'm thinking about at the time.

whats interesting though is when you start arguing with yourself during the discussion... people tend to look at you funny and start walking in the other direction to avoid you... lol

Actually Ed, I did that in fun, I wasn't certain that the thread was even being posted where others could see it without digging into the Komatsu section.
And I did want to share it.
The thing about the Discover card commercial was just because it was fresh on my mind.
The other day at work another mechanic made a remark that we have a mechanic on our staff that would have been a natural for the commercial because he already talks to himself all the time.

I see that you do know that on Internet forums, the only way to get "intelligent conversation" is to reply to your own self...
lol...
But hey, thanx for returning and letting us know what really fixed the problem.

No problem L1ftmech, you're welcome.

Thanks L1ftmech.

Well, this thread has turned out like the Discover card commercials where "we treat you like you would treat you".
Cause of problem identified.
Main injector coil apparently becomes open for just a millisecond or so sometime after the engine starts, causing the ECM to think that injection has stopped and therefore cut power to the interceptor valve. I suspected something like this but I wanted to confirm before arbitrarily swapping parts from the one other Komatsu truck we have here that can serve as a donor, and especially before ordering any new parts.
So I made an extension lead of AWG 18 wire that I inserted into relay terminal #30 (feed out to interceptor valve) of relay # 6 in the EPA relay box on the truck. This extension lead allowed me to "tap into the circuit" and observe the voltage on the circuit, seeing the voltage disappear at the same time the MIL lit up. That was the moment the ECM received the signal that injection had stopped (setting code P1241) and in turn the ECM cuts power to the interceptor valve.
Now I just had to figure out what was causing the ECM to think injection had halted.
To that end I swapped the injector driver module from our other Komatsu -14 over to the ailing truck and the problem persisted.
Next, I decided to swap the main injector. Bingo! With the injector from the other truck, the engine would run just fine and never turned on the MIL.
But just to make the test a double blind thing, I put the injector from the ailing truck in the donor truck and as soon as I started the engine and touched the accelerator, the MIL lit up.
Connecting the reader to the truck showed it also had registered code P1241.
I erased the code and put the donor truck back together with its original parts and put it back to work.
Have an injector coming.

Thanks in advance to the administrator for fixing this double post also (actually, it showed up as a double thread). I wondered if this thread was even showing up in the daily discussions as I have not seen it there myself and it has not gotten any responses so far.