Strange wait light issue

[SgtHulka]

I have a 1992 Hmmwv with a 6.5 GEP.

The wait light was flashing 14 times, all of the time before starting the truck either cold or warm. The truck always started up just fine - never any issues with it starting or running.

I found one bad glow plug so I put 8 new ones in. I also ran a ground wire from the generator to the top of the control box bolts inside the engine compartment just to make sure I had a good ground. I also replaced the TSU with a brand new one from Kascar.

Now, the wait light still flashes 14 times when its cold and then the truck starts up and drives great as it always had.

The weird thing is after the truck gets up to temperature/hot and you shut the truck off and go to restart it, the wait light is a solid yellow light. It doesn't flash when the engine is fully warmed up. Crank it and it fires right back up!

Why does the wait light only flash when the truck is cold or not up to temp? Once shes warmed up, I always get a solid yellow wait light now. Weird...any ideas?

 

[Action]

The light should never blink. And should only be solid on a cold motor. It should not come on with a warm motor. Did you get thd correct TSU or GPC? It must be compatible with your PCB.

 

[SgtHulka]

I sure did get the correct temp sending unit from Kascar. I gave them all of the necessary info off of the box and they knew what one I needed.

 

[simp5782]

I mean simple thing is to verify the voltage out of the controller and see if its a pulse as well as the voltage going into the controller to see if it is a pulse as well.

 

[LouWon]

I replace my temp sending unit and had more problems than before, yellow light stayed , relays clicking, so I ended buying a matched set of the sending unit and controller, of course more $$$, since then no more starting or light issue.
You also stated that you ran a ground, you are best to buy the full ground kit and install it, if you think that you where having a ground issue, one wire from the generator will not help much.

 

[SgtHulka]

How do I verify the pulse voltage? Walk me through it if possible...

 

[Dock Rocker]

How do I verify the pulse voltage? Walk me through it if possible...

I would think plugging a multimeter into one of the unhooked glowplug wires and turning the start switch to on would verify this.

The best way to go about it is start the troubleshooting that is detailed in the –24 manual.

 

[tomelroy]

i have a 94 m998 that does the same thing...starts perfect warm or cold, but blinks about 14 times instead of a solid yellow when cold.

 

[tage]

Holy Charlie foxtrot.

Read the glow plug gospel from years ago.

Bad glow plugs, bad ground, bad box.

 

[Action]

i have a 94 m998 that does the same thing...starts perfect warm or cold, but blinks about 14 times instead of a solid yellow when cold.

Then, I guess it doesn't start perfect!