LT40 glow plug relay

[terrifictimbersllc]

Noticed on the last few jobs that my Kubota diesel (2001 LT-40 super) wasn't starting until the 5th or 6th try.  White vapors coming out of exhaust pretty quick.   Afraid after it gets cold here soon that I might run the battery down, so decided to have a look at it.   Called WM and quickly got to the problem, the glow plug relay was bad.  12V at the red wire underneath when the key was turned on, but no voltage to the glow plug strip.  Same deal taking the relay out and testing it, no continuity across the big copper spades when 12V applied to the appropriate other smaller spades.

Got a new one coming (Lombardini brand), the old one Bosch.   $143 including shipping. 

Made up a jumper wire with alligator clips and applied voltage from the starter motor red wires to the glow plug strip for 10 seconds.   Started on the first try.    8) 8) 8)  Guess $143 is for the convenience of not having to start it this way.   Got 2 jobs Fri and Sat at 92 miles and 59 miles one way so wanted to make sure I could get started.  In the last few times it must have just been starting on compression alone after things warmed up a bit.

[paul case]

when those glow plug relays would go out on old ford diesel pickups it was easier and much cheaper to put a push button in for the glow plugs. many operated like that for decades.  pc

[barbender]

A lot of heavy equipment uses a manual push button for the glow plugs, I don't know if there is a relay involved or not.

[bandmiller2]

TT wile your at it check that the nuts on the glow plug strip are tight,constant heating and cooling tends to loosen them leading to poor conductivity.Frank C.

[MartyParsons]

You can remove the cover on the relay. Sometimes you can solder the terminals and repair. I say sometimes! The relay vibrates and the terminals get loose in side. I have also seen a capisitor come loose inside then you need to discard.
Marty

[terrifictimbersllc]

Thanks, strip is tight.  Got the new one today and put it in, started on first try.   Will dig the old one out of the trash and see if I can open it.  thanks.

[alanh]

Dennis, Keep that mill in tune ,if I keep expanding this deck like I have been I`m gonna need more locust milled up here in Haddam.....I figure it will fall into place around December like last year so it`ll be nice and chilly!
Alan

[terrifictimbersllc]

Alan it was singing today in walnut and cherry!!!  Started at two places on the first try what a difference.

Looking for your deck in these pictures but didn't see it:   http://www.ctrivercandles.com/

Anyway look forward to your call and maybe can save on shipping by picking up some candles too.  8) 8)

[alanh]

Dennis:
No pictures of the finished deck because it's not finished but I have these:

[LeeB]

Same deal taking the relay out and testing it, no continuity across the big copper spades when 12V applied to the appropriate other smaller spades.

Way old thread, but just wondering if you still have those testing procedures for the glow plug relay?

[barbender]

Lee, this doesn't apply directly to your relay, but I had to replace my glow plugs on my Lombardini. Just one was actually bad, but it made for really hard starting. I found they cross referenced to ones used in some VW diesels. I got one from a guy in Michigan off Ebay after I had already ordered a complete set of Monark brand that came from Germany. If you need glow plugs I can dig up the number.As far as that relay goes, I haven't had to work on mine yet. It should just have a hot coming in, then going out to the relay. Then a signal wire from the ignition. The signal should only have voltage when the key is on, the hot in should be hot all the time, and the wire coming out going to the relay should be hot with the key on as well.

[LeeB]

I've got 4 new glow plugs that came with the mill when I bought it 14 years ago. Not sure if I want to spend the money for a new relay or not. Might just wire up a work around switch. Been using a jumper for the time being. Glow plugs are good, just not getting juice to them from normal channels. I'm pretty sure it's the relay but haven't yet checked the ignition switch and other circuits. Weather kinda sux right now to be out in it chasing wires. 

[terrifictimbersllc]

Same deal taking the relay out and testing it, no continuity across the big copper spades when 12V applied to the appropriate other smaller spades.

Way old thread, but just wondering if you still have those testing procedures for the glow plug relay?

Sorry Lee best I've got is what in first post above. Don't have the mill anymore to go look at anything.  Remember wasn't too hard to figure out though once deciphering the wires and jumpers there under the relay. Suggest fixing it right it's good when everything works.

[LeeB]

Went out in the cold this afternoon and did some troubleshooting. Found the relay to be good. It would appear the fellow I bought the mill from put the glow system back to pre-upgrade conditions by adding a timer of some sort that shuts the glow plug power off after about 15 seconds or less, thus not allowing manual control. I just have to cycle the plugs several times to get it to start. No idea why I never had any troubles before. 

[barbender]

My mill has a decal on it for glow plug manual "on" times that I find to be pretty accurate. Goes by temp, and on the low end I think it is 60 seconds. I click my key on, check my oil, tension the band, pick my nose, and then drag my feet over to turn it to start😊

[LeeB]

My mill has the same decal and I always pretty much followed that protocol. A while back I noticed it was getting harder to start the mill and finally decided it was the glow system. If I jumped the plugs straight to hot off the starter hot the mill started no problems, so I have been doing that. It worked well but not the ideal way to deal with the issue so I finally decided to get it back to proper functions. I still need to get more into the wiring because I don't think it's as should be along with what looks like a diode added in the loop. I did check all the cb's today and cleaned the relay receptacle with electraclean, so not sure if maybe wasn't getting good contact before. I don't get a glow plug light when I turn on key. That may just be the bulb or the the wiring may be wrong there too. Still more troubleshooting to do but I did get it to start today without the jumper by cycling the key several times. I checked voltage coming from the relay to the plugs and as I said before, it would switch off after about 15 seconds or less. I'm pretty sure I remember reading a post by Marty or Sparks that older models had this setup and had been revised to a manual operation, hence the sticker showing the glow times. My manuals don't show anything about a timed relay.

[barbender]

Lee, I just had to replace my key switch as the back began to spin in the housing. Out of alignment with the clicks, even though I could crank the mill I realized the light for the glow plugs wasn't coming on. These Lombardini engines are more glow plug dependent than any other diesel I've been around.

[LeeB]

These Lombardini engines are more glow plug dependent than any other diesel I've been around.

True that. They pretty much won't start without 'em,  even in the summer. I do have a new key switch. I may try changing it out but that still doesn't solve the timer issue.

[ladylake]

A lot of heavy equipment uses a manual push button for the glow plugs, I don't know if there is a relay involved or not.

Each glow plug draws around 10 amps, no relay needed with a good switch.  Steve