astra h 1.9 cdti - glow plug / temp sensor problem

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Tue 13 Sep 2016 23:01
astra h 1.9 cdti - glow plug / temp sensor problem - wayneerwin

hi, i have a problem with cold starting, glow plugs will not come on unless i unplug the temp sensor and i have changed every part including plugs, thermostat and temp sensor, glow plug time relay, outside air temp sensor. i am thinking it must be the wiring to the temp sensor from ecu which is shorting making it hink the temp is warmer than it is because when checked on diagnostics it shows a high reading when the engine is stone cold.

i seen this (below) on here from a guy who had a problem but never said if resolved.

A short in the coolant temperature sensor circuit would give a low resistance reading to the ECU-which would be interpreted as high temperature (voltage and resistance drop with increasing temperature).

i am hoping somone can through some light on this for me on how to test wiring from temp sensor to ecu etc.

Reply | Report as offensive | Link
Tue 13 Sep 2016 23:23
astra h 1.9 cdti - glow plug / temp sensor problem - elekie&a/c doctor

Glow plugs are not needed for cold starting on these unless the ambient temp is around 5 degrees or below.Your problem is elsewhere.

Reply | Report as offensive | Link
Wed 14 Sep 2016 09:35
astra h 1.9 cdti - glow plug / temp sensor problem - Railroad.
Modern common rail diesel engines are direct injection. Glow plugs are not needed, or used for preheating prior to cold starting unless the outside air temperature is around zero degrees. Their primary purpose is for emission and noise reduction when the engine is cold, and usually switch off in less than one minute after a cold start.
Reply | Report as offensive | Link
Wed 14 Sep 2016 14:07
astra h 1.9 cdti - glow plug / temp sensor problem - hardway

I would use a rotary resistor pulgged in place of the coolant temperature sensor.

Then monitor the "coolant" temperature on the scan tool to see if what the ECU is "seeing" corresponds with what I dialed into the rotary resistor.

Reply | Report as offensive | Link