M1028 Charging / Starting Problems

[Corvette1974]

Hello.

I just got my M1028, and yesterday when I picked it up it was fine. Started right up, multiple times, and was also driven a lot. Today, when I went to start it, I cycled the plugs, and tried to crank, but it cranked really slowly and didnt start. A few things- The voltmeter yesterday was reading exactly on the line between green and yellow. Today it was in the red and yellow. Is the green/yellow line the correct charging voltage? What could hae killed the batteries or not charged them?

One thing also it I noticed all interior lights work except when you key the ignition to "on", the gen 1 and the oil lights go on, but not the gen 2 light. Does this mean that bulb is out, and IIRC I read somewhere that when a bulb is out that alt wont charge....is that true?

Also, what's the easiest way to charge the batteries, just take them out and charge seperately?

Will

 

[lavarok]

Does this 1028 have the stock CUCV setup or a M1010 charging system?

 

[Corvette1974]

Does this 1028 have the stock CUCV setup or a M1010 charging system?

Stock cucv 24 volt dual alternator system.

Will

 

[Corvette1974]

I took the batteries out and one was pretty well charged (Front battery- took like 3 hours to fully charge on my charger), while the rear battery took almost a full 24 hours to charge and drew more amps charging than the other. The batteries are all new and the exact same model. 810 CCA rating. If one battery was more charged than the other, would that indicate that one alt isnt working? Would the rear battery be charged by alt 2, which is also the alt with the light out? I took the light out and cleaned the corrosion off of the bulb and connector and it should work now, but I'm waiting for paint to dry before I install the batteries.

Let me know if you have any ideas.

Will

 

[Warthog]

GEN2 (passenger) charges the rear battery. If the bulb doesn't come on then the alternator isn't charging.

The GEN2 circuit is more complicated than the GEN1. More stuff to look at.

Start by checking/replace the 24v fuse and then check the voltage on the exciter plug.

24v at all times on the red wire, 24v on the brown with the key on, 0v with the key off.

Many times the exciter plug is nasty dirty and needs to be cleaned or replaced.

 

[Barrman]

Follow the advice in the post above.

The needle on the volt meter should be near the little hash mark in the middle of the green section when running. If yours is on the line between yellow and green, but more in the yellow than green area, you don't have both alternators working. As pointed out above and from your post about the batteries. It looks like your passenger side alternator isn't working.

 

[Corvette1974]

Follow the advice in the post above.

The needle on the volt meter should be near the little hash mark in the middle of the green section when running. If yours is on the line between yellow and green, but more in the yellow than green area, you don't have both alternators working. As pointed out above and from your post about the batteries. It looks like your passenger side alternator isn't working.

GEN2 (passenger) charges the rear battery. If the bulb doesn't come on then the alternator isn't charging.

The GEN2 circuit is more complicated than the GEN1. More stuff to look at.

Start by checking/replace the 24v fuse and then check the voltage on the exciter plug.

24v at all times on the red wire, 24v on the brown with the key on, 0v with the key off.

Many times the exciter plug is nasty dirty and needs to be cleaned or replaced.

OK So I made some progress. I got both lights to work in the dash, the connector was just corroded. Heres how it is now- Key to on, both lights on. Start truck, both lights still on, but once I rev it the Gen1 goes out. Gen 2 is still lit but slightly dim (that could be because of increased resistance due to partially corroded connector still). There are squeaks coming from both alternators, and a belt squeak when revved. Both alternators look original based on the patina and the truck has 34,000 miles on it, so just due to age it's probably time.

What do you guys think? Just rebuild both using this - 2x Alternator Rebuild/Repair Kit Combo - CUCV Electric ?


Will

 

[Corvette1974]

Im ordering the rebuild kits, a new starter relay, and a new GP relay from CUCVElectric.

Will

 

[Warthog]

Do you have a voltmeter? Check the voltage of both batteries. With the truck running and not running.

That will tell you where the problem is.

 

[Corvette1974]

Do you have a voltmeter? Check the voltage of both batteries. With the truck running and not running.

That will tell you where the problem is.

The batteries when running or not running pretty much had the same voltage, maybe a little more when running. The guage also was reading under the middle hash mark, more toward or on the yellow line. I think the gen 2 is not working at all, while the gen 1 is working somewhat lol. Either way, those three things I ordered all need to be done regardless (both alts are squeaking like demons - bad/dry bearings). Based on the trucks life and mileage, I believe both alts are original Mil spec units and are original to the truck. They have to correct "original" patina, too.

I'll make a thread on my truck sometime after the problem is fixed to show the truck off to the forum.

Will

 

[Cletus09]

I am having the same problem...! I bought my m1009 recently and everything worked just fine, except the gen1 light would come on until I ran the engine faster. Then it would go off. And my gen 2 light was not working at all. The truck started fine multiple times after bought it, then all of a sudden, I went out to start it and it just turned over real slow and wouldn't start. I was able to jump start it, i drove it shut it off and immediately tried to start it again... ditto, would turn over at all, but i could hear the starter solenoid clunk. I'm getting 12.5 volts from the front battery and 11.2 from the rear battery. I don't understand it! Also when i got down under the vehicle, the starter was warm, even after a long drive and after being turned off for an hour or two after the drive. I don't even know where to start... I'd appreciate it if you would post whether or not rebuilding your alts worked...

 

[Barrman]

Sounds like your passenger alternator is not working. Your rear battery should get charged and load tested just to make sure it isn't bad. The -20 manual has a step by step section on how to test it. Plus there are many, many threads here about this problem.



Totally separate from that is what sounds like a dying starter motor. Maybe the under volt start caused it, but if it is hot after any start, it is going away. Mine gave me 3 slow starts before it failed to start the engine. You might have already used your warning starts.

 

[WARWAG]

Ditto.

 

[Trailhead 4x4]

I just got a 1028, and of course within a few days of buying it, started having charging problems. My front battery was not charging (lights very dim, wipers hardly able to move) and after searching and reading almost every post I could find about charging system problems, and going cross eyed over the wiring diagram for a while, I finally resorted to an experiment that worked. I attached a temporary ground strap from the engine to the body, and another to the frame, and everything was working again. The next day I removed the temporary grounds, and unhooked and cleaned all of the battery terminals, and every ground connection I could find. Charging system is back up and performing as it should. So when you read on this forum to CLEAN YOUR GROUNDS, it's good advice.

 

[trooper632]

My 1028's needle has always been on the yellow/green line and Ive had it about a year. starts everytime no charging issuses