T273 Glow Plug Timer?

[TYMinColton]

Hi all,

Been awhile, but I'm back. I'm the proud owner of a TYM273 tractor (circa 2005). About 6 months back I developed some trouble with the glow plug system. When I turn the key to the left (position 3), the glow plug "coil" indicator fails to light, and more importantly I no longer hear the timer ticking. These little L3 engines are a pain in the neck to start without preheating the block. I was able to confirm that the 15A fuse for the glow plug system is intact, though I also noted that when I place a voltmeter across the fuse terminals I don't register any voltage, even if I turn the key to supposedly activate the glow plugs (symptom? problem?). I also confirmed that the slow blow 75A fuse is also fine. Based on these symptoms I suspect that either the glow plug timer has died, or perhaps the glow plug relay? I pulled the relay - this is the little do-dad in-line just in front of the battery. See attached pics if you've never seen the relay before (I'm a visual guy). Unfortunately, I don't know of any way to determine if it's the problem. I have contacted a dealer, and I'm waiting on replacement part pricing, but I'm wondering if this is just a timer issue. Has anyone encountered and/or fixed a similar problem? As many of you noted the wiring diagram in the service manual is pretty poor. I'm just not sure if the relay is in front of the timer, behind it, or both. I'm willing to tear into the dash, but I'm not sure what I'm looking for exactly.

Any help would be greatly appreciated!
Thanks!
Pete

 

[TYMinColton]

Quick followup:

I just got off the phone with a TYM dealer, and service provider in Idaho. He indicated that the "timer" sound is actually the fuel pump and that the glow plug timer is silent. He also indicated that the usual failure point for the glow plug system in these tractors is the relay. It's a pretty standard relay you can get a NAPA (part no. AR282). So, I'm going to pick one up over lunch and see if this doesn't address the problem.

More shortly.
P

 

[Bud Soda]

It is just a standard really you can get from a local electronic parts store or online. I had to take mine apart one time because I sprayed water in it and had to clean the contact points.

 

[TYMinColton]

Ugh. . apparently wasn't the relay. Replaced and still no lit coil on the dash cluster and the glow plugs are presumably off. I did checked every 10, 15, and 20 amp fuses in the box outside the firewall and they are all fine. I also didn't see anything obvious (crimping, corrosion) in the wiring leading from the relay back to the dash. Popped the steering wheel and dash cluster and confirmed that the two main 50A fuses are also fine. I did find a few dash bulbs that were out, but not the bulb related to the coil indicator. Checked the harness wiring, and did find some corrosion on a couple of wires connected to the PTO switch. I taped these up, but everything else looks fine to the naked eye. Next, I was able to confirm that I do get 12V from the ignition switch when I turn it to the glow plug preheat position 3. So, that doesn't appear to be the problem.

So, I decided to look more closely at the glow timer. There are 5 wires leading to/from the glow timer (see attached pic Time Pinout.jpg). From left to right and top to bottom, they are Grn; blank; Blk and BLk/Blu; Blk/Red; Red. What I was hoping to find was some combinations of wires that are only hot for 8 seconds after I turn the ignition to position 3. I did find a wire (green) that is hot (12V) when the ignition switch is in position 3, but it immediately returns to 0V when I release the ignition. Perhaps this is the input voltage? The Blk and Red pair not surprisingly are always registering 12V. So, either this is where the problem lies, or it's something on the glow plug side and the timer is simply not seeing a load.

The crappy thing is I don't have a good wiring diagram to better understand what goes to where and why. At this point I'm working my way towards the glow plugs, but also checking some other issues that have me worried (e.g. fuel pump not making a sound during preheat). So, far I have determined that the fuel pump is at least seeing 12V.

Thoughts? Suggestions?
Pete

 

[TYMinColton]

As a follow-up: Good news and bad.

First the fuel pump:
Good news: I get 12V at the fuel pump connector.
Bad news: If I direct wire from the + terminal of the batter to the fuel pump, back through a lightbulb tester, and ground the bulb lights, but pump does nothing. Dead short?

Now for the glow plugs:
Good news: If I direct wire from my battery through the glow plug strip my bulb lights.
Good/Bad news: When I removed the strip connecting the plugs, plug #2 was literally broken in half! :dance1:
Good/Bad news: When I direct contact with my light tester plug #2 is also bad, but plug #1 is fine! :dance1::dance1:

To summarize: (1) My fuel pump is either bad, which would be somewhat odd since I can still start the tractor (gravity?), very quiet, or I just don't understand how it works . (2) Two of the three glow plugs are toast. :thumbdown:

I still haven't determined why the timer doesn't seem to be activating, but perhaps it doesn't work if doesn't see the correct load on the glow plug side of the equation.

Thoughts? Comments?
Pete

 

[Btown]

Did u take off the harness and check to see if it will light up your test light. My guess is that it will. If u have a multimeter u can check the glow plugs. I think it should be on ohms and should read between .5-1.1. But all glow plugs should be about the same. If they are not. Then replace the bad ones. My bad ones all read 0.0. Good luck.

 

[TYMinColton]

I haven't had a chance to fully test the wiring harness, assuming this is what you are referring to. Though it's not some I can take off. What I can do is test for connectivity (open vs closed) from the timer to the relay and relay to the glow plugs.

I haven't checked the resistance of the two unbroken plugs but will do so. There was quite a bit of rust and corrosion on the plug terminals due to mouse pee. Probably led to failure.

Still digging but thanks for the advice
Pete

 

[TYMinColton]

Definitely need glow plugs. Was quoted $40 a piece. That seems pretty expensive. On another thread Jaln generously listed a bunch of cross-listed options. Anyone know if you can get any of these from a local Autoparts store?

CHAMPION CH144
EIKO GF-118
HKT PM79
kubota 15204-6551-1
MITSUBISHI 30666-57301
MITSUBISHI MM401621
NGK Y-110
NGK Y-114T

 

[PILOON]

Search glow plugs on EBay and you will get hits.

NKG should be available at auto parts as long as you have the correct numbers.

 

[TYMinColton]

She's dead Jim. . .


Removed the cover. . . well more accurately destroyed the cover. I took a picture of the components on an old school bread board and it's pretty obvious that the timer is dead. Measured several resistors that are now open, and at least one cap that's bad too. Even if I was able to replace the components, which I'm not since they're embedded in epoxy, it'd probably cost me more in parts than the replacement at $40. The crappy thing is the part is designed to be sealed, but yet there is a pretty large hole near the blade connector. Oregon moisture (or mouse pee) clearly got inside and corroded the parts.

Bummer. . .
P