Glow Plug Relay Question
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Junior User
Joined: Jul 2016
Posts: 55
Likes: 0
From: Bigfork, Montana
My problems mirror yours awhtx. When I put in new glow plugs I noticed each connector was brassy yellowish green from age and thought of taking the harness off and re-doing them with new connectors. Maybe I should do that anyway. All of them seemed to make a nice tight fit though.
I still have no voltage on the glow plug side of the relay (when I reconnected the white wire) after testing.
I still have no voltage on the glow plug side of the relay (when I reconnected the white wire) after testing.
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
Yours is silent.
awhtx's was clicking and clicking, the typical signs of bad glow plugs, Z resistor connections and harness.
I'm curious why awhtx's drop test passed and didn't pick up the bad connection there, it should of.
awhtx,
Does your old controller work?
-Enjoy
fh : )_~
Tuned
Joined: Feb 2006
Posts: 487
Likes: 3
From: Lampasas,TX
I didn't test the old controller as I was just happy to have working GPs. I'm sure the old controller will work though because the old & new did exactly the same thing: click-click-click-click. I'll test it soon to verify.
When I did the "drop" test I connected the large alligator clip to the GP below the connector and above the nut. I was connected to the GP, not the connector.
When I did the "drop" test I connected the large alligator clip to the GP below the connector and above the nut. I was connected to the GP, not the connector.
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Junior User
Joined: Jul 2016
Posts: 55
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From: Bigfork, Montana
Okay both batts are charged and read 13v+ according to my analog multi-meter. After connecting the batts I checked again..both still read 13v+. I then measured the voltage on the incoming voltage at the lug on the glow plug relay and it read 13v. At this point no other terminal or lug on the relay shows any voltage. I then removed the white wire from the relay terminal and taped the end. I put a jumper wire on the terminal. I then connected the pos lead on my meter to the large power lug on the relay and the neg meter lead to a glow plug connector. When grounding the jumper wire voltage reads below 5 and the needle drops slowly. Each plug showed the same voltage. Each time I grounded the jumper wire the relay clicks one time.
I still show power to the large power lug, small red wire terminal and the white wire terminal with the key on...no voltage on the glow plug lug on the relay.
I still show power to the large power lug, small red wire terminal and the white wire terminal with the key on...no voltage on the glow plug lug on the relay.
Thread Starter
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Junior User
Joined: Jul 2016
Posts: 55
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From: Bigfork, Montana
I just found a wire (looks to be black) that's not connected anywhere. It comes out out of what looks like factory wire loom that has 2 wires (both dark blue) that run to the 2 connections above the fuel filter. See pic.
I can't find it on any diagram or schematic I have. Maybe I don't know what it is I'm looking for or at.
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Junior User
Joined: Jul 2016
Posts: 55
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From: Bigfork, Montana
I left the white wire on the controller off and taped, using a jumper wire from the relay terminal to ground for 10 seconds or so, the engine started right up.
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Tuned
Joined: Feb 2006
Posts: 487
Likes: 3
From: Lampasas,TX
I just found a wire (looks to be black) that's not connected anywhere. It comes out out of what looks like factory wire loom that has 2 wires (both dark blue) that run to the 2 connections above the fuel filter. See pic.
I can't find it on any diagram or schematic I have. Maybe I don't know what it is I'm looking for or at.
I can't find it on any diagram or schematic I have. Maybe I don't know what it is I'm looking for or at.
Tuned
Joined: Feb 2006
Posts: 487
Likes: 3
From: Lampasas,TX
Okay both batts are charged and read 13v+ according to my analog multi-meter. After connecting the batts I checked again..both still read 13v+. I then measured the voltage on the incoming voltage at the lug on the glow plug relay and it read 13v. At this point no other terminal or lug on the relay shows any voltage. I then removed the white wire from the relay terminal and taped the end. I put a jumper wire on the terminal. I then connected the pos lead on my meter to the large power lug on the relay and the neg meter lead to a glow plug connector. When grounding the jumper wire voltage reads below 5 and the needle drops slowly. Each plug showed the same voltage. Each time I grounded the jumper wire the relay clicks one time.
I still show power to the large power lug, small red wire terminal and the white wire terminal with the key on...no voltage on the glow plug lug on the relay.
I still show power to the large power lug, small red wire terminal and the white wire terminal with the key on...no voltage on the glow plug lug on the relay.
Now turn the key ON and you should have 13V at the small Red/Green wire on the small relay stud opposite from the small stud the white wire connects to. That provides power to the relay coil and to the controller which should now check voltages and decide to turn the glow plugs ON by grounding the relay coil through the small white wire but it can't because you have it disconnected. Hooking a jumper wire from the small stud to ground bypasses the logic of the controller and forces a ground connection, the relay should close and the glow plugs should receive power. If you connect your voltmeter red lead to the large relay stud where the Z bar connects and the black lead to a good ground, then at the instant you ground the relay you should see the voltage on the meter drop to 5-4-3 volts and then continue to drop until it shows about 2.3 volts after 10 seconds. Do not hold the relay to ground for more than 10 seconds.
Thread Starter
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Junior User
Joined: Jul 2016
Posts: 55
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From: Bigfork, Montana
I believe your right about the water in fuel sensor. Yes the post the 90 degree connector fits on is there at the bottom of the filter. There is no connector so I need to get one. I checked voltage on that wire and it shows just under 10v. I taped the end of the wire for now.
Thanks so much!
Thanks so much!
Methanoholic
Joined: Mar 2009
Posts: 6,442
Likes: 8
From: Maine (NorCal Native)
Where was the other lead of your meter attached?
-Enjoy
fh : )_~
Tuned
Joined: Feb 2006
Posts: 487
Likes: 3
From: Lampasas,TX
"Then ...
Remove the white wire from the small relay terminal.
Set your VOM for 12v+
Connect the Positive (Red) lead of your VOM to the Positive Battery Post, Not the terminals or any other place, to the Battery Post.
Connect the Negative (Black) lead of your VOM to a Glow Plug Terminal without unplugging the Glow Plug, just slip it up enough to hook up. (It MUST NOT touch the wire connector, only the glow plug terminal or it will not test that connection)
Connect one end of a jumper wire to the small terminal on the relay where the white wire was, Hold the other end safe from ground ...
Turn key on (add ignition power to relay, small terminal opposite of where the white wire was, ie Red Ignition wire).
Now, touch the Jumper wire to ground for no more than 10 seconds ... Take note of the voltage."