M1028 Question

[Sam06]

I have a 1984 M1028 CUCV that has been converted to a "Manual" glow plug switch. The truck is hard to start and I suspect the GP's are either bad or going there. I plan on testing them today with a ohm meter and replacing them with wellman 070's. I have 3 questions:

1. With the manual GP switch, how long should I keep them on before starting. Is there a too long on time?

2. The Generator light on the left side stays on until the accelerator pedal is pushed then it goes out. I have checked the belt and it is tight.

3. The battery closest to the cab runs down after a week or so. I am not sure if its due to the Battery cables which are not the best or if this could be connected to the Gen light.

Thanks in advance for any help and answers, I am a new CUCV owner but I have driven them before when I was in the Army(25 years). I had one at FT Polk JRTC and its was bomb proof and hands down the most capable off road truck I have ever driven that is the reason I bought this one.

 

[dependable]

AC 60s have proven to be a more reliable plug than the Wellmans. Best if you replace in sets.

1. If glow plugs are working, 10 seconds usually is enough, a little longer if it is very cold out. If you run glow plugs too long, they can burn out, although the AC 60s are somewhat better in this respect.

2. Sometimes it takes a little more RPMs to 'excite' the alternator, there is not necessarily anything wrong with it.

3. Charge and load test batteries, it is best to replace series connected batteries in matched sets.

Most of above info, and much more is included in the electrical system 'stickys' in the CUCV forum on this site. Makes for good reading for any new CUCV owner.

 

[Sam06]

AC 60s have proven to be a more reliable plug than the Wellmans. Best if you replace in sets.

1. If glow plugs are working, 10 seconds usually is enough, a little longer if it is very cold out. If you run glow plugs too long, they can burn out, although the AC 60s are somewhat better in this respect.

2. Sometimes it takes a little more RPMs to 'excite' the alternator, there is not necessarily anything wrong with it.

3. Charge and load test batteries, it is best to replace series connected batteries in matched sets.

Most of above info, and much more is included in the electrical system 'stickys' in the CUCV forum on this site. Makes for good reading for any new CUCV owner.

Thanks for the info. I have been looking around here some and have answered a few of the questions I have. I just checked the GP's and 6 are bad. I ordered the wellmans before I read this but I am sure they will be fine. I just hope they are not swollen and cause problems getting them out.

 

[MarcusOReallyus]

3. The battery closest to the cab runs down after a week or so. I am not sure if its due to the Battery cables which are not the best or if this could be connected to the Gen light.

Bad cables aren't going to drain a charged battery, but should be replaced for other reasons. It's hard on your batteries and on your starter to have to fight bad cables.

Battery discharge means that something is drawing ccurrent when it should not. That can be one of the alternators. Test it by charging both batteries and then disconnecting the alts. Check voltage. Let it sit a few days and check the voltage again.

There are also some diodes on this beast that can cause a battery drain. See the electrical sticky.

 

[Sam06]

Stopped the order on the Wellmans and went with the AC Delco 60G Glow Plug. From reading here and other places with the Manual GP switch I need to have the self limiting ability of the AC 60G's.

 

[MarcusOReallyus]

Great! Now to find that battery drain. The horn circuit can do this, as can a bad alternator.

There is a thread on "why is my headlight fuse melting", which is well worth reading all the way through, which explains why the horn can drain the battery. There's a wealth of info on our electrical system in that thread. Following the logic on that thread is will be very helpful to you.

 

[Warthog]

I have seen many times that a bad trio-diode in the alternator will drain a battery

 

[Skinny]

A regulator can do the same. I remember reading a trick using a screwdriver to see if the alternator is still fielding after the engine is shut down.