Glow plugs don't fire when warm

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fen
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Location: Boise Idaho

Glow plugs don't fire when warm

Postby fen » Sat Jul 07, 2018 1:42 am

I've got a little issue with my glow plug system. When the engine is cold, the glow plug system appears to work correctly.

If I drive around and warm up the engine, and doing something for a little while (an hour or two) and the engine cools down, but not all the way cold... the glow system doesn't seem to work and the truck won't start. Usually I have to hit the override by turning the key to start with the clutch out and cranking for a bit...

It looks like I have a busted cable under the hood on the circled part. Unfortunately it's busted right at the base making reattaching the cable quite difficult. I wonder if this is the culprit. Anyone know where I could find this part?

pup_engine.jpg
'81 diesel P'up dlx 5-speed 2wd short bed
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L Autotragic

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puttputtinpup
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Re: Glow plugs don't fire when warm

Postby puttputtinpup » Sat Jul 07, 2018 5:47 am

If the wire is broken off at the sensor, you can do what many of us have done. Take a dremel and clean away enough of the resin around where the wire came out of the sensor. Then solder a new wire onto the exposed prong. Then mix up some epoxy and build back up what you ground away. This may or may not fix the starting issue. You can only try

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fen
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Location: Boise Idaho

Re: Glow plugs don't fire when warm

Postby fen » Sat Jul 07, 2018 8:54 am

That's an idea to try! I'm guessing it's some kind of temperature sensor. It seems like the glow plugs don't want to fire when it's above 80-90 degrees out?
'81 diesel P'up dlx 5-speed 2wd short bed
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L Autotragic

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JoeIsuzu
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Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: Glow plugs don't fire when warm

Postby JoeIsuzu » Sat Jul 07, 2018 8:59 am

If that sensor is disconnected (broken wire), your glow plugs should fully cycle as if cold -- regardless of temperature.

Jack

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fen
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Location: Boise Idaho

Re: Glow plugs don't fire when warm

Postby fen » Sun Jul 08, 2018 12:52 am

Hmm maybe it's something else. I think there's another wire connected just below that one that has an iffy connection too so maybe that one is causing it
'81 diesel P'up dlx 5-speed 2wd short bed
'82 diesel Chevette (Isuzu 1.8L 4FB1) 4 door 5-speed
'99 Isuzu VehiCROSS 3.5L Autotragic

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puttputtinpup
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Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Glow plugs don't fire when warm

Postby puttputtinpup » Sun Jul 08, 2018 3:13 am

There's a connection with several wires in it up close to the firewall between the wiper motor and valve cover. Clean up that connection as best you can also.