glow plugs coming back on

[84cucv1ton]

after the truck is warm the wait light always comes back on. never did that before. i can shut it done go back in 10 min and the wait light comes back on. any idea thanks

 

[doghead]

Maybe a bad temperature sensor for the glow plug controller. I believe the TM has a test procedure.

 

[84cucv1ton]

didnt think of that thanks

 

[84cucv1ton]

to think of it. what happens when the glow plugs are on and you start it? so far i have heard 3 people say nothing at all. just wondering, still need to test mytemperature sensor

 

[cucv1833]

I was reading the sticky-Glow Plug Module Technical Description and decided to do a search I have the same problem but thats because my TEMP SENSOR is disconnected due to having a temp gauge installed in that location. will this create problems in the long run. the truck starts fine. the plugs cycle even when the engine is warm so should i let it cycle through or crank normally once warm Thanks

 

[antennaclimber]

If the temp sensor is high in resistance (open when its disconnected) during the start up sequence, the GP module will leave the wait light on for the maximum amount of time. As the sensor warms up the resistance lowers and the wait light will not stay on as long.

It would be best to have a resistor value of 6.2K ohms across the temperature sensor input to simulate an approximate temperature of 50 deg F. Or simply leave a sensor connected and it will give the GP module the value of the ambient air temp. This would be better than no resistance at all.

If your wait light is coming on after the engine is started, then I would suspect a bad GP module or possibly the GP module is not seeing the ignition sense from the vehicle.

Interesting problem, I will see if I can recreate it on my GP module tester in the lab.
Karl

 

[cucv1833]

Karl, thanks alot i understand now. i think i got the temp sensor in my glove box i will hook it up like you said for abient temp. the wait lights cycle like there suppose to and dont come on after the engine is running. they just come on for the full 15 sec. when the enginge is warm due to the resistance problem

Thanks again

 

[Warthog]

Is this the Glowplug system tempature sensor or the coolant light temp sensor?

By your description you disconnected the coolant light temp sensor and it has nothing to do with the GP system.

 

[cucv1833]

Is this the Glowplug system tempature sensor or the coolant light temp sensor?

By your description you disconnected the coolant light temp sensor and it has nothing to do with the GP system.

on my truck i have both engine oil pressure and water temp gauges installed on the driverside rear of the engine block and 2 sensors disconnected.

the TM-34P looks like the water temp sending unit is on passenger side rear which is untouched.

during start up i only get the Gen 1/2 warning lights to come on. no 4WD or temp i have done the istrument cluster clean up already.

please advise if i missed something

Thanks