[JLanzino]

Thats where the glowplug inhibit sensor goes on some models. On others it's at the back near the fireall on the pass side, just behind the intake runner

I have the Cold advance solenoid connector on the pass side at the back of the engine. I attached a image of whats on the pass side of the engine

 

[JLanzino]

This is the missing Glow Plug Sensor

 

[smackzed]

No above the cold advance plug. That should be at the bottom in the block or maybe it's the lower head...below the glow plugs anyway. This is just behind the intake runner hard to see unless you crawl up in there. 2 prong sensor just like that

 

[smackzed]

a glowplug sensor? never seen one of those. The glow inhibit and the coldadvance sensor are identical...on my '87 with '88 motor it was in the cross over or close to it somewhere. On my '90 with '92? motor it's in behind the intake runner

 

[JLanzino]

Ill take a picture in the morning of my other 6.2 with both sensor locations. Ill also have to look to see where the cold advance solenoid is on this truck just to be sure

 

[smackzed]

I ahven't seen a 6.2 yet with a cold advance in any other location but pass side lower head upper block. As a test to see if it's the glow inhibit...unplug the sensor. if glows don't come on with the key then it's glow inhibit. If they still come on then it isn't

 

[turbovanman]

Some have the other sensor, some don't.

 

[JLanzino]

How could I wire one in to help the GP's for the correct timing dependant on the temperature of the coolant

 

[smackzed]

How could I wire one in to help the GP's for the correct timing dependant on the temperature of the coolant

Hmm not sure what you're asking...One what? The glowplug controller should turn the glow plugs on for different times dependant on the temp of the engine normally.

Are you asking how to compensate for the slower heating plugs? If o there is a mod where you put a resistor in somewhere but not sure where. I believe happypunch did it and wrote a how to.

 

[battlecomedown]

I have a '91, and the only temperature sensor I have is in the coolant crossover. I made sure that I didn't have the separate coolant temperature sensor for the glow plugs. However, I do have a port on the rear passenger side head that's been blocked off, which makes me suspect it's an older motor.

From reading the Haynes Diesel manual, I was under the impression that the glowplug coolant sensor was for the older glowplug systems. According to the troubleshooting chart in the manual, the newer systems use the sensor in the coolant crossover pipe to activate the inhibit switch. Please correct me if I'm wrong.

 

[smackzed]

There are a few variants. I believe you're right and the sensor that JLanzino posted is for an earlier style glowplug controller but having no experience with them i couldn't really say. Some of the later trucks have the glow inhibit sensor in the crossover as yours does, others have the glow inhibit sensor in the rear of the head behind the last runner of the intake on the passenger side, opposite to where the glow controller mounts. Whether the glowplug controller uses the glow inhibit as a sensor for glow duration as well is very possible, some have thought that it used the mounting bolt and an inner sensor since it mounts in that water plug.

If anyone ever had a definitive answer to this I've never seen it

 

[seo]

I think that a lot of the circuitry in the cold-start of the 6.2 has to do with exhaust emissions at start, not starting ability. Because my automatic cold start didn't work, I just replaced it with a manual switch, and rely on my own sense for knowing how cold it is, and how long the engine has been sitting to guide me in whether to count to five or ten before lighting it off. On cold days I usually roll the engine over a couple of turns before initiating the glow plugs.
Once the engine is started, I keep the glow plugs on for the count of five, and then look at the exhaust. If it's real smoky, I turn the plugs on again for another five count. I'm not saying this is the "right way," but it works for me up here in Maine. That, and I do have a block heater for REALLY cold days.

 

[turbovanman]

The older systems, IE the bullet controller had a seperate temp sensor, then the next step has either a temp sensor or its built into the controller, then the ECM takes over in the next system, IIRC.

 

[smackzed]

I think that a lot of the circuitry in the cold-start of the 6.2 has to do with exhaust emissions at start, not starting ability. Because my automatic cold start didn't work, I just replaced it with a manual switch, and rely on my own sense for knowing how cold it is, and how long the engine has been sitting to guide me in whether to count to five or ten before lighting it off. On cold days I usually roll the engine over a couple of turns before initiating the glow plugs.
Once the engine is started, I keep the glow plugs on for the count of five, and then look at the exhaust. If it's real smoky, I turn the plugs on again for another five count. I'm not saying this is the "right way," but it works for me up here in Maine. That, and I do have a block heater for REALLY cold days.

The glowplugs get no info from the exhaust, anything to do with cold tempos and the exhaust are the EGR and EPR. The J code engines have the same controller but have nothing between the manifold and the tailpipe

 

[seo]

I was mainly saying that the glow plug system controller is probably set up to remain on for a certain duration after the engine has started, and there's maybe there's feedback from the coolant temp sensor deciding if glow is needed, and maybe how much duration after start. This automation is nice, as long as it works.
For myself, I like diesel engines that don't have a lot of wiring involved in the fuel system. My 3208 cat is completely non-computerized, doesn't have glow plugs, and I don't use the ether system, and the damn thing still starts very reliably.
I once had a German man admire my Mercedes 123 5 cyl 3 liter turbo diesel, and tell me to take care of it, because it was the last car Mercedes built that didn't have a computer in it.
I'm sorry to be a luddite, but computers belong on your lap, not in your car.

 

[smackzed]

Most of us here feel the same. we drive 25 yer old mechanically injected trucks for a reason