1989 M998 6.2 Strange Stalling Issue

[isaacnasar]

Hey Guys,


I'm having a strange issue with my HMMWV. I did a search of the forum and couldn't find any posts with a similar issue. SS has been a huge resource for me in maintaining my MV's and I'm hoping some of you more knowledgeable guys can steer me in the right direction.

This seems to only be a problem when it's raining or very humid.

When it's dry, the truck starts well. No Smoke, no Stalling, no Surging. Glow Plugs Work and it has the Kascar Grounding Harness installed.

Sometimes when it's wet or it could just be humid out, it will start but only stay running while the starter is engaged. The second I back off the start position and put it back in run position it dies. When starting the Voltmeter is between yellow and green, the second I put it back in the run position it is as if everything dies. The Voltmeter shows nothing as if there is no current at all. If I leave the key in the run position, after about 30 seconds the box under the dash (Nartron Yellow Label) will make a thump/click type of sound, the Voltmeter will show in the green again, the WTS light will blink, and if I try to start it again the same thing will happen. The Engine runs until I back off the starter and the electric is cut off again.


Sometimes I can get it to start after 10 or 12 attempts, and others I just let it sit for a day and start it when it's dry.

Additionally, and this is very rare, but 1 in 50 times I start it the starter will spin but not engage. It will usually only happen once and on the 2nd attempt the starter will engage and the truck will start.



Any thoughts?

 

[isaacnasar]

I did quite a bit of research today and my conclusion is that the EESS is on it's way out - It's a yellow Label NARTRON 19207 ASSY 12469158-1

For the guys that have have been down this road before - is it wise to replace with the same model or upgrade to an S3 EESS. If I were to go with an S3 I would need a new Temp Sensor and just to be safe I would replace all glow plugs. At the moment 6 of 8 are working.

 

[ryanruck]

If you've got to replace it, I'd just go with the S3. Some nice features and improvements the "dumb" boxes don't come with.

My green label KDS hiccuped on me once (glow plugs didn't fire a couple times) and started working again but, I took the opportunity to upgrade to an S3 with no hesitation. Don't regret it a bit!

I've kept the green label as a KDS as a "just in case" spare.

After you replace it, maybe you can open it up and refurb your old box as an emergency spare...

 

[isaacnasar]

I removed the EESS and opened it. It is clean as a whistle. Not a speck of dust or any corrosion on any wires or the circuit board. Is there anything else that can be causing this?

 

[Action]

The box would not cause the starter to not engage the "flywheel".
What happens if you are driving it and a cloud appears and starts to rain?

 

[isaacnasar]

Once it's started and running it is fine, even in a heavy rain it won't stall it.

I figured the starter may be on it's way out but it seems to work 99% of the time so I haven't messed with it.