24v glow plug help...

[SNLC]

So I have this Japanese 24v diesel 4x4. From the factory it came with an auto glow plug system. But the previous owner had unhooked it. I assume he did this because it wasn't working and the parts are big bucks to buy. Now that is all fine and dandy, I don't need the auto-glow plug system right now and that is not what I need help with.

The previosu owner put in 12v glow plugs which he wired through a 12v solenoid or relay. This is pulling power off one battery and has a wire to a push button on the dash. This worked ok when it was warm out but now it is getting colder, ie in Wyoming that is below freezing. But I don't like 12v stuff in my 24v system and I want nice hot glow plugs for the cold starts I have to deal with over the next 5 months.

I bought 24v glow plugs for my diesel motor, these are made for my motor not just some generic stuff. I then replace the 12v solenoid with a 24v one. But since it is only pulling power off one battery I am pretty sure I am still only supplying 12v to the solenoid and glow plugs.

How do I wire up the new solenoid so that I am supplying 24v to the glow plugs? I know it must be simple but the way I tried it the second power wire got hot and started smoking. So I unhooked it.

 

[brownbear]

Get your power off of the top battery in the series. SO you will see this in the main cables. Negative to frame/engine....posisitve to negative.. then then the positive to fuse block inside stuff... The last battery I described is the top battery. Get your power from the same place the fuse block and systems get power and you have 24v.

If you went to the positive terminal on the other battery that leads to the negative on the other you haVE 12Vs.

Also you can take a multimeter, set it on volts. Put the black probe to the engine, and the positive to the terminal you want to read, it will say what voltage is where.

 

[brownbear]

If I was going to a manual homemade glowplug set up....

I would buy a heavy duty relay, with enough rating for glowplugs... (80 amps?)

I would get a fuse box from an auto parts store. Mount it on the upper fender. Put in an appropriate fuse for the glowplugs. Run a heavy wire like 10 gauge from the battery to the fuse block. Then to the relay(solenoid). To the large main terminal. Then from the relay to the most back glowplug. Then join all the glowplugs from the top posts to each other. This puts them in parallel. Again use 10 gauage and appropriate ring terminals to the glowplug stud size. The glow plugs get ground thru the base to engine.

Now for relay control I would run a fused wire to the switch(push button only) then to the field coil of the relay. This wire must be fused before the switch. As sometimes coils short and a direct to ground can happen and cause a fire.
Some relays need a ground wire for the field coil, some ground to the base(either way) you need a clean bare metal ground.

Now when you push the button the field coil engergizes and the main contacts close giving battery power to the glow plugs, which ground thru the block.

Sounds easy. It is. Most difficult part is finding the fuse size. And not undersizing the wire.

 

[SNLC]

Ok I understand everything you said. I could wire it all up the way you have described which I just may do....it sounds like the best way to do it and makes sense. The way it is wired up now was done by the p/o and I just copied it when I put in the new parts.

I guess what is confusing me is that the 12v relay/glow plugs was wired off the positive terminal on the top battery. That is where the truck has 24v and that is where I have the new 24v stuff wired from. So why 12v stuff wired off the top battery? Maybe the p/o just didn't know what he was doing? The 12v stuff was working just fine I just don't like 12v parts in my 24v system. Plus it is my understanding the 24v is for cold climate. It is cold where I live and I am looking to have easier starting which is why I removed the 12v stuff and put 24v parts back in place.

It was getting dark last night. I will put a volt meter on it this morning and see what I get.

 

[SNLC]

Well it turns out I am getting 24v to the glow plugs and also to the relay. Unless my pos cheap gauge is wrong or I am to stupid to read it I think I am actually getting 30v to the relay/glow plugs. The gauge is telling me 30v in the relay, 30v out and 30v at each plug. This being wired up exactly the same as how it was wired with 12v stuff.

Now I bought a 24v relay from Napa, the expensive one that is internally regualted. This relay is giving me probs. It only seems to work when the truck is cold and I haven't started it yet. It works for the first glow but after that no power through it. Perhaps it got damaged when I was farking around with the wires? I am not sure but couldn't start the truck with it. So I put back the 12v relay which is working fine and allows me to start the truck. The 12v relay has the same power in and out and to the glow plugs. It works every time I push the button. Now I would be worried but this 12v relay has had the same power through it since beofre I bought the truck (nearly 4 years) and there is no problems. When I get a chance I am returning the 24v relay to Napa and see if I can't get a new one.

Seems a little odd a 12v relay is taking 30v and is still working just fine. This is also the root of my confusion here...