PCB removal

[TwoStates]

Bad PCB and need help with removal

I drove my HMMWV to work today, but I noticed that the wait light flashed on and immediately off when I turned the key. I let it sit for about 10-15 seconds and then turned the key to start and it started up. When I started it during this occasion the pulsating of the volt meter did not result as usual.

My Are there any tricks to removing the PCB? The wiring attachment points that have the large nut which attaches to the PCB (both under the hood and in the cab) seem very tight. Is there a particular tool to loosen them or do I need to just try harder? Thanks.

 

[teteacher101]

Mine were pretty snug also, I gently used a pair of pliers an once I got it to move some I sprayed the connectors with penetrating lube an worked them back an forth.

 

[Action]

Those connectors can break.

 

[papakb]

Do a search for spanner wrench on eBay and you'll see the proper tool to remove those connectors without tearing them up. They're cheap and replacing the connectors isn't.

Kurt

 

[1 Patriot-of-many]

A big pair of slip joint pliers works fine

 

[TwoStates]

I got the PCB replaced with a smart box and a yellow banded TSU. Initially, everything worked after I hooked it up. the wait light came on and went off after about ten seconds. It started right up with no issues. The glow plugs were firing like they are supposed to. I let it sit for about ten minutes and then shut it off. About twenty minutes later I tried to start it up again and no wait light. Could I have done something wrong? Did I blow something up? Is there something I should have replaced besides just the TSU and the Smart Box?

 

[Action]

If the WAIT light does not come on, you just start it. no light means no wait! I think it is time to read the owner's manual on how to start it....It isn't an "I come on every time you start me" light.

BTW, did you disconnect the batteries while replacing the box?

 

[1 Patriot-of-many]

I got the PCB replaced with a smart box and a yellow banded TSU. Initially, everything worked after I hooked it up. the wait light came on and went off after about ten seconds. It started right up with no issues. The glow plugs were firing like they are supposed to. I let it sit for about ten minutes and then shut it off. About twenty minutes later I tried to start it up again and no wait light. Could I have done something wrong? Did I blow something up? Is there something I should have replaced besides just the TSU and the Smart Box?

20 minutes? The temp was probably up to 120 degrees.....

 

[TwoStates]

If the WAIT light does not come on, you just start it. no light means no wait! I think it is time to read the owner's manual on how to start it....It isn't an "I come on every time you start me" light.

BTW, did you disconnect the batteries while replacing the box?

Yes, I disconnected the batteries. The wait light always came on with the old PCB before it broke, that is why I was concerned. Maybe I'm not real familiar with the smart box.

 

[Action]

If you thought the old box was good, then why did you replace it?

 

[TwoStates]

If you thought the old box was good, then why did you replace it?

I never said that. The truck wouldn't start with the old box. This morning everything worked as I think it should. I got a wait light and it started up with no issues. I drove it to work and hopefully it will start at lunch.

 

[TwoStates]

It all worked like it is supposed to today! I am a happy guy! It is a great feeling when things work like they are supposed to!

 

[kfrosty]

I think you would be best served reading up on why diesel engines have glow plugs.

http://www.enginebuildermag.com/2012/01/diesel-engine-glow-plugs-not-just-for-starting-anymore/

(These are older engines.)

I have 5 hmmwv's, new S3 boxes, TSU's etc. One sometimes I get the wait light, sometimes it blinks. Then after it's warm as has been pointed out you may not see anything.

Also, here is a link to a TM I'm actually going through right now. I have a new truck to me with 1100 miles. It looks like it just came out of service and everything works but the wait light. It never comes on but the truck starts just fine. (It's still warm enough outside.)

http://www.steelsoldiers.com/upload/M998/TM-9-2320-280-20-1.pdf

If you're wait light comes on every time, even after the engine temp is above 120 degrees, then actually it's not functioning properly. However, it should still start.

 

[Action]

If it is warm enough outside for your cold engine to not need glowplug activation, it will likely be too hot for you to be outside.
The engine should start in like 1 second. If you have to crank it for 5-7 seconds to start it, something is wrong with your system.

 

[kc5mzd]

If it is warm enough outside for your cold engine to not need glowplug activation, it will likely be too hot for you to be outside.
The engine should start in like 1 second. If you have to crank it for 5-7 seconds to start it, something is wrong with your system.

I see you are from Cincinnati I noticed the glow plug issue was in Texas. Your hottest day of the year would be like a cold front blowing through Texas.

 

[Action]

I see you are from Cincinnati I noticed the glow plug issue was in Texas. Your hottest day of the year would be like a cold front blowing through Texas.

Nope, I haven't updated it yet. I now live in SW Florida, a couple hours from Miami. With the heat index over 100, I still get a wait light on a cold engine. I use a white label KDS Smart Start box.

 

[kc5mzd]

I was in central FL this summer and it certainly was very hot and humid. I hope to be bringing home a m998 here in central TX in a couple of weeks. Supposedly it starts and runs but overheats after 20 min or so. I am guessing it is probably a temp sensor or something... I have several older military trucks and my rule is if it is to cold to start without glow plugs then stay inside, I guess the m998 will need them even in the summer...