Electrical Problem

[Randyw]

I am new to the site and have to say its a great one. I have a 84 CUCV M1008 that I have had for about a year. The truck has been great and have not had any issues until recently. I know this has probably been talked about but I couldnt find anything on it.


So here it goes! Wednesday of last week we had our first real cold snap, about 32 degrees. I went out to get in the truck and it would not start. The truck just turned over with excess white smoke coming from the exhaust. I figured it might be the glow plugs so I ran down and picked up 8 new plugs. Once they were changed I still could not get the truck started. The glow plug wait light has never worked in the truck. So, I located the module card and noticed one of the diodes on it was loose and had pulled out one of its prongs. I pushed the diode back in and the wait light lit up. Hit the key switch and the truck fired right up. After driving the truck for a few minutes I noticed smoke coming from under the hood. I opened the hood to find smoke coming from the resistor in the back. After looking on this site I found a thread that talks about the resistor and said it was normal for the resistor to smoke due to dirt or bugs. After driving a little while longer it seemed to have stopped smoking. When I parked the truck for the night and then went out the following morning hit the key and nothing, no power at all. Checked the batteries and both were dead. After putting two more charged batteries in the truck it fired right up. took it for a spin and when I got back the truck sat for about an hour. Went to get in it and no power at all again. Checked the batteries again and both were wiped out. What can be causing this? My first thought would be the GP relay and it may be but I recently put a new one on because the old was chattering. Any help on this would be great. Thank you!

 

[Warthog]

Something is staying on. You will need to find out what that is. Very possible that the GP system is staying energized.

What GP relay did you install?

 

[Howlin Mad Murdock]

Welcome to SS Randy!

It sounds to me that your GP relay is stuck on. Others will have to correct me if I am wrong but when you put in a replacement relay, I believe that you are supposed to hook up the ground differently which if not done will leave it stuck on. Also, you most likely want to do the resistor pack bypass mod which you should be able to find and do extremely easily and in a short amount of time. Hopefully this will be able to help!

 

[Randyw]

Warthog, The relay I bought was a BWD S55 from Oreilly's. Murdock, I didnt hook the ground any different I installed the same way the old one was connected. I started reading up on the resistor by pass. I would like to keep it stock if possible. But if not I may just do it. Thanks guys!

 

[Warthog]

How are the wires hooked up to the relay? The is an error in the wiring diagrams.

 

[Randyw]

The large red wire coming from the resistor pack is connected to the top terminal. Orange wire is connected to the bottom large terminal. the top small terminal has the small blue wire connected to it and the bottom smaller terminal has the small red wire wire connected to it.

 

[JH1]

You might also have blown up the new glow plugs in the process of leaving them on inadvertently. They are only designed to be on for a few seconds to a minute. If you can't start it well now, you might check the resistance of them to ground, either individually or as a full set. Individually, they should be under 1 ohm or so. All 8 together would be 1/8 ohm or so.

I recommend not even using the automatic glow plug systems, and just install a momentary push button switch and a heavy relay (or also known as a contactor) to supply power to the glow plugs. Just push and hold the button for 10 seconds, and then start it. Remove finger. I trust my fingers more than fancy electronics, and I've been in fancy electronics for over 40 years.

 

[Randyw]

Thanks JH1! I think once I find out what the problem is I am gonna put the push button switch in.

 

[doghead]

1-3 ohms, read the TM.

 

[Hasdrubal]

Just push and hold the button for 10 seconds

I find that the AC60's require more burn time to get up to temperature for a quick start and smooth idle. Although my wait light, right now, goes out after 8 seconds, I hold it for an additional 8 seconds. Good rule of thumb; double the wait light time. Of course you still have to manually afterglow also. A quick look at my chart shows 8 seconds gives 1463 degrees, while 16 gives 1821 degrees.

 

[Randyw]

Ok Guys,

I ordered a new GP card that I got on Friday and I also purchased the BWD S603 GP relay. Installed both items and the truck fired right up. I noticed the relay cycleling the GP and everything seemed to work just fine. I let the truck sit overnight and went this morning to try it with the weather being in the 30s. The truck fired right up with no problems. So its seems the electrical problem is fixed. Thanks to all of you for the good info.

 

[Warthog]

Goon news. Glad we could help.

 

[2deuce]

What is the purpose of the after glow? For extreme cold? or is it a result of the card only and not needed?

 

[Warthog]

The after glow helps to continue to heat the cylinder so a complete burning of the fuel happens. Saves fuel and saves contaminating the oil.

while not totally needed it is very beneficial.

 

[Skinny]

Stabilizes combustion until the diesel is capable of igniting on its own by compression.