M923A2 starting issue

[NJDEUCE]

My M923a2 has a gremlin I have not been able to figure out. When I go to start it cold, usually it will chatter the starter a couple quick times and then fully crank and start right up. Once it warms up a little bit and I shut the engine down and I attempt to restart the truck it will just chatter the starter but not turn over. My suspicion is that it is the PCB box from doing some research. Sometimes when I smack the box with a hammer it will start up fine but other times it doesn’t matter how much I whack it. So I’m not sure if that is definitely my issue. My other suspicion is the batteries, but I have had this issue with fully charged batteries. I’m reluctant to spend the $250-$400 they are asking for PCB boxes just to take a shot in the dark that it is in fact my issue. I did remove the box and open it and did not find any corrosion. I was hoping to rebuild it, but it is the newer style box (with copper bridge) and I have not found much info on the process.

I guess my biggest question is what should I do to narrow down my issue. Thank you for any advice.

 

[Mullaney]

My M923a2 has a gremlin I have not been able to figure out. When I go to start it cold, usually it will chatter the starter a couple quick times and then fully crank and start right up. Once it warms up a little bit and I shut the engine down and I attempt to restart the truck it will just chatter the starter but not turn over. My suspicion is that it is the PCB box from doing some research. Sometimes when I smack the box with a hammer it will start up fine but other times it doesn’t matter how much I whack it. So I’m not sure if that is definitely my issue. My other suspicion is the batteries, but I have had this issue with fully charged batteries. I’m reluctant to spend the $250-$400 they are asking for PCB boxes just to take a shot in the dark that it is in fact my issue. I did remove the box and open it and did not find any corrosion. I was hoping to rebuild it, but it is the newer style box (with copper bridge) and I have not found much info on the process.

I guess my biggest question is what should I do to narrow down my issue. Thank you for any advice.

.
Crack open the cover for the PCB. If it looks white and powdery inside, you found the problem. Rather than buying one, you might use the search function here and rebuild what you have. Another possibility is to search on YouTube for instructions on rebuilding it yourself.

It might be that just replacing the solenoids is what you need... Especially if hitting the box makes it work again.

 

[simp5782]

The newer style box is a pain to rebuild. You can gut it and make your own. Or call Memphis equipment and see if they will sell you a core old style box.

Zip tie your fuel solenoid back or remove it. Jump the starter with a screw driver. if it's the PCB it will run fine with no Power at all

 

[NJDEUCE]

Thanks for the quick replies guys! Yea I did crack open the box and it looked just fine to my eye. There’s definitely a whole lot of extra junk in there that the other boxes I’ve seen being rebuilt by you Wes on YouTube don’t have. I’ll probably end up trying to find a good take out box.

 

[NJDEUCE]

Just for future reference for anyone searching the problem was the PCB. I gutted my newer style box like Simp5782 advised and rebuilt like the older version with new solenoids. Worked like a treat. My truck never started up this well. Thanks again Simp5782 for the the advise and YouTube videos that made it possible for me to figure my way through.