This excavator is new to me its a 2011. The glow plug do come on but not long enough. It's on for maybe 1-2 seconds at 25 30 degrees ambient temperature. So I was wanting to check and or replace the sensor. I can't seem to find the location of it for sure. I believe I found two temp sensors on the 85d. One would be on the engine near coolant thermostat. The other is at cab blower input area. Is it one of these or is there a third one?
Link to page from Deere online parts catalog . https://partscatalog.deere.com/jdrc/sidebyside/equipment/69891/referrer/search/pgId/779605 .
I did find a third one right under the one on the engine ... just unplugging it caused glow plugs to max out on 10 seconds?
thanks dave I saw that ... evidently that is a new version my 2011 has two with in 0ne inch of each other .. it was just hard to see .. besides the temp gage acted proper ... now I wonder if they are same part number hmm
The temp sensor for the temp guage is # 4676171 . The particular parts page is not clear on the location. The temp sensor for the glow plugs is # 8970633010 and the location is shown in the original pic I sent. The other temperature related item at the thermostat housing (also shown in pic) is # 8971256001 and it’s a temperature Switch to indicate engine overheating.
Interesting Dave ... I see now item 44 says its a plug but on mine there is a sensor in that port just below item 38 which is also sensor ... by reason of isolation (unplugging sensor in port 44 leaving item 38 plugged in) I get the temperature gauge working and the glow plug time longer like 10 seconds ... with 44 plugged in the glow plug time is too short 1-2 seconds .. I think or hope leaving it unplugged is OK i like it better .. I am thinking the sensor in port 44 tells brain its warm enough to start and glow plugs shut down. Its bad is likely .. but is it 8970633010? my guess is the 2011 is different from present diagrams.
As you can see the temp guage sensor location is not clear. I would think it is located in the thermostat housing as you described. I’m sure the glow plug sensor part number is correct just the location is at the #44 plug .
Thanks Dave ... no its not clear ...have you fixed the glow plug (time on issue) I am experiencing? ... I will buy one and try it , more than likely it uses same sensor.
The parts page shows no serial # breaks involved for the glow plug temp sensor so there should no issues with the part # 8970633010 . No, I have not come across the glow plug (time on) problem you’re having .
You could measure the ohms of the temperature sensor to see what it reads. Unfortunately, the lowest spec in the manual is 77*F which should be 6840 - 8360 ohms. Colder temps will drive the ohms up.
hmmm thats why when I disconnect the wire the ohms would max out thus increasing the time the glow plug lights up ... do you think any harm would be done to let glow plugs max out on time all the time? ... and does starting it before the glow plugs finnish does that end the cycle ...
I believe the glow plug timer might keep cycling without a signal telling it is over 50*C. Check your PM's.