Wait light behaves normal but no amp draw and hard starting

[Kevin Donahue]

Issue is as title says. I have the newer smart start box (nartron) paired with the yellow band temp sensor.

Turn key, wait light on for 10-20 seconds, no amp draw shown on Guage, Humvee starts hard like it's got cold plugs... I also don't here clunking of relays anymore, but not sure if that's typical of this box.

Gonna go through connections tomorrow but what do you guys think?

Thanks and Merry Christmas!

 

[TOBASH]

It your box and glow plug sensor are mismatched this will happen

 

[NDT]

The new boxes have solid state devices to switch the glow plugs on and off, not a relay. I would ohm out the glow plugs to start with, maybe they are all burned up.

 

[Kevin Donahue]

The new boxes have solid state devices to switch the glow plugs on and off, not a relay. I would ohm out the glow plugs to start with, maybe they are all burned up.

I figured that may be the case with the new boxes. I just replaced all glow plugs thinking the same thing so that is probably not the issue. One thing I am thinking is maybe my batteries are just bad. Idk but seems logical the box would behave like normal but not have the power to warm the plugs fully if batteries were low/bad.

 

[Coug]

have a helper with you when you try to start it, have them read the voltage at the batteries when you turn the switch and when it's cranking.

You should see a voltage drop when the glow plugs come on, and another when you go to crank it. (poor man's load tester)

If it drops below 20 volts when cranking the batteries are definitely suspect.

(batteries should read at least 25V when you start this process, if below that put them on the charger overnight and try again)

 

[papakb]

Pins V and W on the STE/ICE connector are connections directly to the battery + and - so you can connect your meter there and read the battery voltage as you try to start the truck.

Even though you've jusy replaced the glow plugs go back in and read their resistance to see if they're still functional. They should read under 10 ohms if they're good.

 

[Thumper580]

I figured that may be the case with the new boxes. I just replaced all glow plugs thinking the same thing so that is probably not the issue. One thing I am thinking is maybe my batteries are just bad. Idk but seems logical the box would behave like normal but not have the power to warm the plugs fully if batteries were low/bad.

Kevin, on the right side of the engine there is a heat shield... Did you take it off to get the glow plugs out? And if so how did you get the shield off? I don't think the glow plug removal tool would fit with the shield in place.... Thanks. Sorry to hijack without an answer to your post...

 

[papakb]

Most of us don't even have those heat shields fitted because they don't do much other than get in the way.

 

[Thumper580]

Most of us don't even have those heat shields fitted because they don't do much other than get in the way.

I didn't put them on and would like to find out how the right side one comes off....

 

[Action]

I didn't put them on and would like to find out how the right side one comes off....

There are 4 holes in the shield. Use a long socket and remove 4 of the exhaust manifold bolts. There is a nice drawing of the process in one of the TMs.

 

[papakb]

With the very limited clearance along the right side of the engine and the wierd angle the hex bit needs to be at this is one miserable job and you can see why no one tries to do this with the engine in the truck!

 

[86humv]

Nartron and KDS

 

[Kevin Donahue]

I didn't get around to it today but I will probably ohm out the plugs tomorrow just because its easy and might as well. Did the voltmeter on the batts with the wait light on and saw a slight drop, maybe less than half a volt. IDK if that is normal or indicative that not all glow plugs are getting warmed. Feel like it should be more than that though. I am wondering if I can just pop each cap of the plugs one by one and check voltage by putting my positive lead into the plug cap/lead and my negative on the block somewhere?

 

[Kevin Donahue]

Nartron and KDS

This is interesting. Not sure why I ended up with the wrong temp control for KDS and not the Nartron all this time. I just ordered the correct one though from Hummer parts guy so we will see if that does anything. Thanks for the info!

 

[Kevin Donahue]

Update:

Ohm out all plugs, they are within spec about 4-6.5 ohms was what I was constantly getting.

Decided to get somewhat creative and ran a wire from the 24v negative battery post to the neg probe on my voltmeter. Then I struck the pos prob onto each glowplug lead and tested individually. All showed a bit over 24v while wait light was on and 5v after which I assume was an afterglow procedure. Correct me if I am wrong.

All that being said, it does not appear to be an electrical issue. I am thinking maybe fuel.

I will keep everyone posted!

 

[Kevin Donahue]

Another update: started checking over other suspect electrical components. Thought maybe the cold advance solenoid could be bad. Seems as if the switch is doing its job and supplying 24v when engine is cold according to my multimeter, also clear that the solenoid itself is getting power.

I don't really know how to verify the solenoid is doing anything but I guess the obvious way would be to unplug it and plug it back in with the truck idling. Probably will give that a shot tomorrow. I tried firing truck up with the solenoid unplugged already tonight and no noticeable difference what so ever so I think I may be on to something.

When I jumper the switch I do hear a faint "click" but it doesn't sound like its coming from the solenoid or anywhere near the injection pump. Sounds lower and driver side of the engine maybe.

What do I need to do if that solenoid is bad? Hopefully not have someone rebuild the IP lol....