Glow plug issue I presume?

[flan]

My PD's glow plug light came on for about 3 sec this am and shut off so I went to start and it ran but pumped out blue smoke and stumbled for about 10 sec. It was 30deg out. Glow plug issue I presume? No cel on. First winter with this car.

 

[Powder Hound]

Time for a new coolant temp sensor.

 

[vw monster]

glow plugs don't turn on till 0 so I think I would check timing or bad injector .

 

[freakwithracket]

0c is 32f. The glow plugs start working right around 40f from what I recall.

 

[flan]

I have read the gp's start to function around 50 degrees. As far as the coolant temp sensor suggestion is there a way to test it? The gage on my dash appears to work fine, after about 5-10 min of driving the gage sits right at 190 where it should.

 

[BobnOH]

I have read the gp's start to function around 50 degrees. As far as the coolant temp sensor suggestion is there a way to test it? The gage on my dash appears to work fine, after about 5-10 min of driving the gage sits right at 190 where it should.

yes, when it's cold unplug the coolant sensor and see if the plugs stay on much longer. A better test might be to check it with VCDS.

 

[Vince Waldon]

The gage on my dash appears to work fine, after about 5-10 min of driving the gage sits right at 190 where it should.

So that you're not misled as you troubleshoot... the coolant temperature sensor is actually two sensors... one for the glowplugs and one for the dash gauge.

And, for some reason, failures seem much more common on the glowplug side.

 

[freakwithracket]

Yeah, you need to check the sensor with VCDS. The Coolant sensor is actually two sensors in one. One side of the sensor feeds the ECU, and the other side feeds the gauge on the dash. Because of that, the gauge on the dash could be spot on, but the temperature reading that the ECU and by extension the GP relay gets could be totally wrong.

 

[Alchemist]

A lot of the 04 engines were subject to a recall to replace the fragile ceramic glow plugs with more robust steel plugs. The steel plugs were 5 volt as opposed to the original 7 volt ceramic. There was a reflash of the ECU to adjust the voltage, but that often resulted in hard or no start when cold.

VW eventually came up with a newer version of software to make the engine start when cold, and at the same time replaced the 5 volt steel plugs with 7 volt steel/ceramic ones.

It may be helpful for you to contact a dealer and find out which, if any, of the glow plug revisions have been installed on your car.

Another possibility is the PO replaced the glow plugs with the 11 volt plugs as used in ALH engines.

The temperature sensor has two sections, one for the gauge and one for the ECU. To test the ECU portion, you will need to have VCDS and compare the coolant, fuel and intake air temperatures after the car has been sitting overnight. If one is much different from the others it is suspect.

If there was a bad plug, you would have a CEL, so that is not a problem.

 

[flan]

Awesome I'll unplug it in the morning and see if the light stays on longer and the smoke is gone it should be cool enough around these parts tonight. If that doesn't work I'll start digging into the recall end of it.

Thanks for the replys

 

[flan]

Ok so I got curious and just went out to check this thing and here's what I learned:

1-I have the green sensor (replacement?)
2-The clip for the wire harness plug is gone, plug pulled right out.
3-With sensor plugged in 1 sec of glow plug light, with it unplugged 5 sec of glow plug light.

 

[flan]

I just wanted to check with the more knowledgeable folks if its a good idea to go ahead and order a new coolant temp sender after the results I had found
Thanks