This should not be red! Busbar attachment glowing!

[modustollens]

The secondary glow plug relay on my machine was fried and given where I am a new one I have not. Plus the wires are old and frayed and I suspect shorting out somewhere too. So, I wired up some manual switches. I have had great success, as I reported here:

http://www.nissanpatrol.com.au/forums/showthread.php?15888-Manual-Glow-plug-switch-success-work-report!

But since I had a new engine installed I have not been having so much luck. I put a manual switch on my first relay too for it was not delivering power at start-up. I made another manual relay for the second glow relay just like the first one I made (the first one I made I moved to the glow relay one, and it seems to be working fine). But unlike my earlier success this new one for the secondary glow is not working out:

Click for picture (it is blurry but it will show what I am talking about)
http://www.imagerocket.net/photos/sm_1381899983_IMG_20131012_122509.jpg (http://www.imagerocket.net/view.php?pic=1381899983_IMG_20131012_122509.jpg)

Where the wire attaches to the bus bar, the nut is becoming red hot. In fact, all the plastic has melted off! I replaced the wires to the relay with larger ones; cleaned all the melted plastic. But, still no luck: this morning again it was glowing red hot. The relay I bought is rated for 80 amps. And it is not getting hot. Maybe the ground on my relay in insufficient? Or is the relay ground only for the switching of the relay?

I did not have this problem with the other two manual relays I wired, and they are wired the same as this current, overheating one. The first time I wired a relay to the secondary glow busbar it would never get that hot - and since I lack skills I am not sure what I can try next. I think there is either too much current or too much resistance; I beefed up the wires to the relay but that, obviously, did not work.

Any suggestions? Is there some test I can perform on the busbar itself - maybe it is cracked? I have yet to take it off and inspect it; though this is on my list; but it was snowing this morning and last Friday too so I'll have to wait for a warmer day. The back window was falling out of the door; so, when the weather was fine yesterday I resealed that - my results were messy buy effective and I don't think it will fall out anymore. That was a more urgent job than the secondary glow relay; but with the temperature getting lower every day and snow already falling I want the glowing and heating circuits to be working, though not getting so hot that it starts a fire.

MT

[happygu]

Looks like resistance in the connection.....

make sure that everything is really clean and shiny ... no dirt and no corrosion.

Mic

[happygu]

And make sure that the conection is tight too...

[modustollens]

I did clean everything up; buffed it with sandpaper until it shined. I'll tighten it up and check again - perhaps is it something simple that I overlooked.

Thanks

MT

[Yendor]

It very hard to tell from your photo. Does your new engine have 2 busbars like your first engine? or does it only have one busbar?

Did you use your old glow plugs? or the ones that were in the new engine?........if you used the ones in your new engine did you test them?

I'm not sure how you have wired up relay 2. Relay 2 is a change over relay.

When glow plugs 1st stage is active, relay 1 switches power and relay 2 switches earth.

When glow plugs 2nd stage is active, relay 1 is off and relay 2 switches power.

With the manual override you don't really need the 2nd stage. Once the vehicle has started you can just pulse the 1st stage on and off as required.

[modustollens]

I am not sure what you mean by 'change over relay.' But the relay for the first and second are wired in the same way (according to the scheme I posted earlier).

I think they used the old busbar; but of that I am not certain; and I think the plugs came with the engine and I doubt they tested them. I will take the busbar off when the weather is fair soon and test everything there. Perhaps there is an insulator or something missing?

The second relay is sending power to the plugs for my meter measures it. And when he switch is on the engine runs much smoother in the morning when cold. The engine heats up pretty quick - after 5 min the glow plug warning light stays off.

I have been doing as you suggested - i just manually press the 1st relay button (which must be held down to stay on - it turns off when no pressure is on the switch); or I cycle the second relay toggle. So, it is not a major, pressing issue yet.

Perhaps there is a short in the wire going to the busbar?

This is odd for this is the third time I have wired the relay - and I have always done it the same way - and I never had this problem before.

Anyway, I am going to take the busbars off and inspect and clean them and test the plugs; maybe that is where the issue is?

Thanks,

MT

[Yendor]

A change over relay has two sets of contacts. When the relay is in the rest position pins 3 & 4 are connected. When the relay is turned on pins 3 & 5 are connected (refer attachment). If you wired the second relay up the same as the first relay what did you do with the extra wire? Relay 1 has 4 wires, relay 2 has five.

Does your engine only have one busbar now?

If it still has two busbars and you don't have the fifth wire connected at relay 2. You will only have the first 3 glow plugs heating up when you manually push relay one button.

Back to your other problem, yes it could be a problem with the insulators or a faulty glow plug causing that connection to heat up.