Weird Start Problem - Battery smoke?

[Tanabi]

Hey there;

I've got a 1989 M998 HMMWV with a strange starting issue that has cropped up recently.

When I turn the ignition (I have the keyed ignition upgrade) to the mid position, WAIT light comes on, everything seems okay. I crank it, and it makes sad noise like there's not enough voltage going to the starter, and usually it just dies and loses electric.

So, I go to the battery box, and fuss with the cables a bit -- wiggling what's on the post -- go back, this time I blow past WAIT and just crank it. Starter sounds strong, it cranks good, and it starts in the glowplugs-didn't-actually-cycle kind of way (it's hot enough out that I don't need the glow plug to start, but that first cold start takes more cranking than usual).

This has happened maybe twice before, between instances of the truck starting normally otherwise. Well, today, it happened... and I jumped out, went over, opened the battery box and there was smoke in there. Nothing seemed hot and I couldn't tell what had happened in there. I wiggled the cables again, and once more blew past WAIT and it started as noted above.

The battery posts are dead clean, the first time this happened I cleaned everything up good (honestly they weren't at all gross to begin with -- I used dialetric grease when I installed these batteries over a year ago). One thing I've noticed is that my battery meter is just a little below the 'happy line' but still in well the green most of the time when I'm driving. Is that a sign that the batteries aren't getting charged? is this a weak battery thing, or a your-glowplug-controller is dying thing, or a your-battery-cables suck thing?

Let me know your thoughts, and thanks!

 

[98G]

I suspect bad ground...

Got a grounding harness installed?

 

[Tanabi]

Got a grounding harness installed?

Sure do. I have the KASCAR harness installed.

 

[Tanabi]

Got a grounding harness installed?

Also, in case it is relevant, I have upgraded to the 200 AMP alternator. This was about a year ago.

 

[papakb]

One of the problems with voltmeters instead of ammeters in the charging system is that if you have poor connections anywhere in the charging system a voltmeter will display good voltages but you won't have the current flow you need to rejuvenate the batteries. An ammeter on the other hand shows the actual current either being drawn from the battery or going into the battery to charge it. Voltmeters simplify things because they only need one wire connected to the battery while ammeters either have all the system current running thru them or need a shunt system to handle it. The old Dodge 880s had everything running thru the dash gauge and were known to melt instrument panels or wires from time to time.

Take a good look at where the cables enter the battery terminals and see if you have corrosion there and like 98G said a bad ground can cause problems too. Crawl under the truck and look at the connections on the starter since that's the first place the power goes after it leaves the battery box. People tend to ignore the battery box mounted shunt but the connections there need to be clean and tight too since all the system current flows thru it. While it's only purpose is to provide a signal to the STE.ICE testers t still needs to be maintained. I've also seen the inter-battery jumper cause problems.

 

[frank8003]

How many grounds are in a HMMWV like you have?
It is DC current that makes it all work as you know.
Remove clean EVERY ground everywhere, that is my apprenticeship information from men long passed now.
I am never going to be able to even drive a HWWMV but all the information you need is within SS website.
When the heading says smoke and battery I get concerned.

https://cse.google.com/cse?cx=partn...steelsoldiers.com/search.php?searchid=6796707

 

[Tanabi]

Thanks guys -- I will start going through all the groundings and see if that helps. I guess I was overconfident in my grounding harness and didn't even consider that it could be a ground problem.

 

[NDT]

Next time it “loses electric” leave the switch on and open the battery box and start taking measurements. Smoke came from an intermittent connection that is in there not elsewhere. Look for crusty dust between the cable strands and cable terminals.

 

[Retiredwarhorses]

Get rid of the cheap keyed ignition switch, it’s the number 1 problem I see in the shop, these cheap POS are not rated for 24v. Put your old one in, get a 2 position switch and tap off the run switch, you will now turn the key the energize the run lead only, leave the key in the on position for as long as you drive it, remove it, and the OEM 3 position start switch is dead.
kascar sells this switch....I use nothing else for keyed switch and have never had a problem.

 

[Tanabi]

Get rid of the cheap keyed ignition switch, it’s the number 1 problem I see in the shop, these cheap POS are not rated for 24v. Put your old one in, get a 2 position switch and tap off the run switch, you will now turn the key the energize the run lead only, leave the key in the on position for as long as you drive it, remove it, and the OEM 3 position start switch is dead.
kascar sells this switch....I use nothing else for keyed switch and have never had a problem.

Is this the switch you are talking about? The description on the Kascar site is ... very lacking

https://real4wd.com/store/Switch,-Keyed-Ignition.-For-Humvee

I've had some oddities with my ignition switch before (very rare) so I could believe this is a problem. I'll also be going through my battery box and cleaning everything per the other fellow's suggestion.

 

[frank8003]

golly, it is always a ground problem
Like, Niagara falls on one side, and no where to go on the other side...................

Like the young guy on Saturday night
200 amps and nowhere to go

 

[Retiredwarhorses]

Is this the switch you are talking about? The description on the Kascar site is ... very lacking

https://real4wd.com/store/Switch,-Keyed-Ignition.-For-Humvee

I've had some oddities with my ignition switch before (very rare) so I could believe this is a problem. I'll also be going through my battery box and cleaning everything per the other fellow's suggestion.

That’s it, easier to call them, ask for Mike or Ron.

 

[Milcommoguy]

" I used dialetric grease when I installed these batteries over a year ago"

Where's the "DIELECTRIC" grease going? Dielectric is another word for INSULATOR. If smothered between the posts and contact surfaces of the cabling, this is going to be a problematic.

Bone dry connections are best, proper torque, then some kind of dielectric coating to keep air and moisture out. Maybe hard to completely seal so keep and eye on connections during PM's.

And ditch the keyed switch. Can be done with quality Cole Hersee products. > http://colehersee.com.au/product/marine-3-position-ignition-switch/ <

Always something to check, CAMO

 

[G3isMe]

Get rid of the cheap keyed ignition switch, it’s the number 1 problem I see in the shop, these cheap POS are not rated for 24v. Put your old one in, get a 2 position switch and tap off the run switch, you will now turn the key the energize the run lead only, leave the key in the on position for as long as you drive it, remove it, and the OEM 3 position start switch is dead.
kascar sells this switch....I use nothing else for keyed switch and have never had a problem.

I was actually going to start a thread asking this very question. Thank you for this post as it answered all of my questions regarding this setup. I was originally thinking of using a hidden in plain sight toggle switch but the keyed switch is a much better option.

 

[Tanabi]

That’s it, easier to call them, ask for Mike or Ron.

Thank you, sir! I have ordered it and I will try it out.

 

[Tanabi]

" I used dialetric grease when I installed these batteries over a year ago"
Where's the "DIELECTRIC" grease going? Dielectric is another word for INSULATOR. If smothered between the posts and contact surfaces of the cabling, this is going to be a problematic.
Bone dry connections are best, proper torque, then some kind of dielectric coating to keep air and moisture out. Maybe hard to completely seal so keep and eye on connections during PM's.

And ditch the keyed switch. Can be done with quality Cole Hersee products. > http://colehersee.com.au/product/marine-3-position-ignition-switch/ <
Always something to check, CAMO

I had it on the outside, yeah, just to keep the moisture out. The first time I had this start problem, I cleaned every little bit of the dielectric stuff off *just in case* I had it wrong, and that didn't fix it. I'll be unbolting everything in the battery compartment and giving it a thorough scrub as soon as the heat lets up a little.

 

[Tanabi]

So! For anyone curious, here was the problem.



On the negative terminal that connects to the truck, the cable was just loose enough on the bolt that it didn't have a good connection and was arcing. When I would go into the battery compartment and wiggle the cables around, it fixed the bad connection, which is why the truck would start when I did this. However, as the truck would run, the connection would wobble loose again.

I didn't notice this damage because this is the underside of the terminal; the top side actually looked perfectly normal, and the connection wasn't so loose that it was visually obvious. But, each time it arcs, it would make that puff of smoke, so that's where my smoke was coming from. It actually arc'd so much that it cut through the eyelet of the cable, and I was able to pull the cable off the melted terminal with very little effort.

I went ahead and cleaned all the ground connections up in there while I was doing this, and I replaced the battery cable and terminal. Totally a newbie mistake, I should have looked at the underside of the terminal when this first started Fortunately nothing caught fire, burnt down, etc. in all this.

 

[Retiredwarhorses]

So! For anyone curious, here was the problem.

View attachment 772303

On the negative terminal that connects to the truck, the cable was just loose enough on the bolt that it didn't have a good connection and was arcing. When I would go into the battery compartment and wiggle the cables around, it fixed the bad connection, which is why the truck would start when I did this. However, as the truck would run, the connection would wobble loose again.

I didn't notice this damage because this is the underside of the terminal; the top side actually looked perfectly normal, and the connection wasn't so loose that it was visually obvious. But, each time it arcs, it would make that puff of smoke, so that's where my smoke was coming from. It actually arc'd so much that it cut through the eyelet of the cable, and I was able to pull the cable off the melted terminal with very little effort.

I went ahead and cleaned all the ground connections up in there while I was doing this, and I replaced the battery cable and terminal. Totally a newbie mistake, I should have looked at the underside of the terminal when this first started Fortunately nothing caught fire, burnt down, etc. in all this.

When checking any battery connection, user needs to grab and attempt to loosen by hand any battery connection, if it moves in anyway, it too loose. I generally replace all 4 of the battery terminals on all the trucks I get in and clean everything up, as well as secure the batteries with the battery retainer.

 

[Mogman]

I would be very concerned if you can "wiggle" the battery connections, these MUST be clean and TIGHT!