High idle cold and glow plug disable temps? (93)

[WarWagon]

Looks like you have to floor it before starting to enable high idle...

I would like to know if the glow plug inhibit switch and the high idle are the same or separate sensors? What temps do they kick off at?

I have a reading a couple notches over the lowest setting on the temp gauge and get glow plugs from time to time. Not consistent and I am extremely concerned about glows when the engine is too hot. (Blew 8 plugs in half on a 6.2 when that happened due to the glow temp switch being bad.)

 

[bk95td]

On my 92 the glows come on at start always. engine temp doesn't seem to matter. I looked at the scematics once and didnt see where there was any connection to a temp sensor for glows on a non-egr engine. My 91 6.2 had a sensor on the back of the passenger side head by #8 injector[coolant port]. That sensor isn't there on my 92 and 93 6.5s. The glows blowing apart on your 6.2 were more likely the old style non regulating 8 or 9gs. I would like to know what controls glow time and after glow on the 92-93s so I can modify it to glow longer without having overide switch.I don't believe it's the pcm because the manual trans trucks didn't have a pcm.

 

[bison]

As far as i know the temp switch (closed when cold)on the pass rear of head kicks the IP's internal cold start high idle solenoid in and out.
The high idle solenoid on the trottle lever applies only after the trottle is bumped up,i'm not sure what operates that sol,could be the CTS?
thats on my 98 6.2 anyway.

 

[bk95td]

On the 92-93 6.5s the only temp control for the high idle and cold advance is the coolant temp SWITCH[not sensor] in the coolant crossover. No other temp switch on the rear of passenger side head. At least on the "F" engines.
The coolant temp SWITCH closes[on] at temps below 70f or somewhere near that.

 

[midniteplowboyy]

All glow functions/sensors are built into the relay itself on the 92-93's. The relay senses engine temp itself. Has signal wires from ignition run and starter, thats it, IIRC.

Throttle does need to be depressed a little with key on to allow high idle to set. Starting instructions should be on the drivers sunvisor.

IIRC, the temp switch should be closed below 100ºF, as mentioned its in the coolant crossover(same place as the newer CTS are) on the 92-93's. Very common item to go bad, they dont last like they used to, AC/Delco ones only last me a couple years now.

AC/Delco Switch P/N 10154649

 

[WarWagon]

Good info as 99% of the time my high idle doesn't work. I have seen it work once since I bought it...

One more thing to throw a part at...

Knowing there is a separate sensor explains why one works and the other doesn't.

 

[kimagine]

Would this have anything to do with the coolant level sensor wiring as well?
Since the tranny rebuild and the tcm replacement, aside from getting the code 68, my high idle will not work when the pedal is depressed in 20 degree temps after not being started and not plugged in as well as the low coolant light coming on while it's plenty full.
I know, I have lot's of issues...):h

 

[bison]

Would this have anything to do with the coolant level sensor wiring as well?
Since the tranny rebuild and the tcm replacement, aside from getting the code 68, my high idle will not work when the pedal is depressed in 20 degree temps after not being started and not plugged in as well as the low coolant light coming on while it's plenty full.
I know, I have lot's of issues...):h

The low coolant light could be a bad sensor.Same for high idle sol.

Did you Ohm the 2 VS sensors? I had one that went haywire when the tranny warmed up

 

[bk95td]

Just reread the original post. my 91k2500 LD w/egr 6.2 would do the same thing as far as the glows coming on while driving and cold advance. It had the sensor on the rear of the passenger side. If I wiggled the connection on that switch it would turn off. Seemed to do it after crossing railroad tracks. When i pulled the engine the switch on the rear of the passenger side head was crispy. It broke to pieces when i unplugged it. If yours has that switch I'd look at replacing it. I've had the one on the coolant crossover go bad and it never caused the glows to come on while running.

 

[WarWagon]

The 1993 cold advance is now working along with the high idle. The switch in the crossover was bad.

The old 6.2 experience makes me nervous. I'll check for the other sensor, but I doubt it applies on the 6.5. And yes that sensor going out was the reason for blowing up the 6.2 plugs - too hot and the injection pulses blew em in half. This was proceeded by a glow plug controller failure rattling when kicking off due to a failed solder joint on the board. This burned out the original plugs. The aftermarket plugs with a new controller were supposed to be immune to burning out but got too hot... Nothing like feeling the plugs get crushed up going down the road with the engine jerking the whole suburban!

 

[WarWagon]

Would this have anything to do with the coolant level sensor wiring as well?
Since the tranny rebuild and the tcm replacement, aside from getting the code 68, my high idle will not work when the pedal is depressed in 20 degree temps after not being started and not plugged in as well as the low coolant light coming on while it's plenty full.
I know, I have lot's of issues...):h

Low coolant sensor is a metal blade in the radiator. It senses a current path through the coolant to ground. Usually they get crud in them and don't tell you when the coolant gets low for a few min. Long enough to crack heads when you blow the block heater out or split a hose. :mad2:

So your low coolant problem is a bad connection. Specifically a 'open' like a cut in half wire or corrosion on a connector. Maybe the sensor blade is eaten away in the radiator. Could also be a frame/body ground issue.

I bet mine has more issues...

 

[bk95td]

Nothing like feeling the plugs get crushed up going down the road with the engine jerking the whole suburban!
OUCH!!