Why no glow time?

[AlexP]

Jetta 01. Have had GLow plug blues. Replaced them/harness/relay. Juice at relay's large lug. VAG-COM says the glow interval is 0.00 seconds. No CEL light. Starts hard with lots of smoke. Can't be glowing. Seems like some relay must be misreporting. VAG-COM indicates 27C for air and fuel on 70F day. Seems resonable. Anyone know what to check? Thoughts?

Thanks Alex

 

[pepper10]

Glow plugs are not activating because it is not cold enough outside. I would check your timing. Sounds like it's a bit off.

 

[VelvetFoot]

You could simulate colder conditions by disconnecting the electrical lead from the coolant sensor. It should glow for 20 seconds or so.

 

[GoFaster]

Jetta 01. Have had GLow plug blues. Replaced them/harness/relay. Juice at relay's large lug. VAG-COM says the glow interval is 0.00 seconds. No CEL light. Starts hard with lots of smoke. Can't be glowing. Seems like some relay must be misreporting. VAG-COM indicates 27C for air and fuel on 70F day. Seems resonable. Anyone know what to check?

NOT the glow plug system. It is CORRECTLY not operating at that temperature. The engine should start without any glow plug assistance at that temperature. SOMETHING ELSE is wrong.

More likely, your injection timing is too far retarded. It's also possible that the cranking speed is too low (weak battery / bad starter motor).

 

[Yz2K130]

Where is the coolant temperature sensor located on a Jetta with the automatic transmission? I couldn't find it when I tried to test the relay.

 

[jim223]

I seem to be having the exact same problem...got the 16764 / P0380 code (Glow plug/heater circuit electrical fault (Q6)) Intermittant fault code ('01 Jetta too). I tried to check the system according to Glow Plug 101 v2 (plugs checked out OK) but I cannot find the coolant temp sensor nor the coolant glow plugs. Could someone please tell me where to find the sensor. Your help would be appreciated!

Jim

 

[Curious Chris]

Item 6 is the temperature sensor.

And the words that go with it are:

6 - Engine Coolant Temperature (ECT) Sensor -G62-
Color: blue
For engine control module
with Engine Coolant Temperature (ECT)Sensor -G2-
Before removing release pressure if necessary


Unplugging this will give you a nominal 20 second glow plug on time as the ECM thinks the car is really really cold.

 

[jim223]

Thanks a bunch Chris. That was perfect. For some reasonI just couldn't figure it out from the picture in the Glow Plug 101 post.

Jim