This truck was sent to our shop because another shop had been unable to solve a starting and running problem.
Though communication between the 2 shops is scant at best, the complaint was that the engine was usually difficult to get started requiring a long crank period and when it did finally get running it did not want to accelerate.
Upon arrival at our shop the reported condition would occur about 90% of the times we tried to start the engine.
Using our Hitachi diagnostic reader (SST) I found 3 stored codes:
P2138, P2122, and P0650.
The P065 was simply that the MIL lamp was missing from its position in the monitor panel (perhaps left out intentionally?)
The other 2 codes suggested to me that the APPS (which appeared to be brand new!) might not have been properly adjusted and given the proper "learning" procedure.
Using the SST data display I adjusted the APPS to the correct voltage range, then I ran the idle fuel learning exercise with the SST.
Doing this apparently "solved" the starting and running issues on this truck because since doing this, the engine starts quickly and accelerates readily every time it is cranked.
My concern is that I have no previous experience about what problems failure to adjust a new APPS and administer the learning procedure will cause. Our shop has never replaced an APPS without adjusting and "teaching" it so we don't know for sure if we have actually addressed the root cause or not.
All I know about the "original problem" that caused the other shop to replace the APPS with a new one is that the truck suddenly would only idle and would not accelerate.
Just wondering if there are any Komatsu or Nissan K-21 techs reading this forum that might have experience to whether the APPS settings could have been the problem ever since the other shop replaced it.