DanG144
Top Post Dawg
I had seen the question asked several times, but not definitively answered.
So I tried to find out. I force the CGPs on one day, and let the car idle for 20 minutes. Then the next day (almost identical temperature profile overnight) I forced them off and did it again. I recorded the temperature data with VCDS, then graphed it in a spreadsheet.
It showed about a 30% faster warmup with the CGPs forced on.
It was very noticeable.
This also caused the engine to have a higher temperature through the slow speed country drive to work, and when I did turn on the cabin heater fan, it was noticeably warmer.
Fuel consumption showed an increase from .4 lph to .6 lph.
Alternator load showed roughly a 37% increase.
The engine actually showed a speed variation at idle (maybe 20 rpm) until the ECU re-learned the new idle parameters.
I liked the faster warmup, so I left my CGPs forced on for the winter.
I did not approve of the way I forced them on for the experiment (simply grounded the control relay's output's), so I am working for an improved method, such that the CGPs will be on any time the engine is running, but turn off when the engine dies. I will either do this with a vacuum switch or a relay that works with the lift pump circuit.
This thread is a good informational thread.
http://forums.tdiclub.com/showthread.php?t=7107&highlight=coolant+glow+plug
But the method suggested here did not work on my PD.
http://pics.tdiclub.com/data/500/coolant_glow_plugs.PNG
So I tried to find out. I force the CGPs on one day, and let the car idle for 20 minutes. Then the next day (almost identical temperature profile overnight) I forced them off and did it again. I recorded the temperature data with VCDS, then graphed it in a spreadsheet.
It showed about a 30% faster warmup with the CGPs forced on.
It was very noticeable.
This also caused the engine to have a higher temperature through the slow speed country drive to work, and when I did turn on the cabin heater fan, it was noticeably warmer.
Fuel consumption showed an increase from .4 lph to .6 lph.
Alternator load showed roughly a 37% increase.
The engine actually showed a speed variation at idle (maybe 20 rpm) until the ECU re-learned the new idle parameters.
I liked the faster warmup, so I left my CGPs forced on for the winter.
I did not approve of the way I forced them on for the experiment (simply grounded the control relay's output's), so I am working for an improved method, such that the CGPs will be on any time the engine is running, but turn off when the engine dies. I will either do this with a vacuum switch or a relay that works with the lift pump circuit.
This thread is a good informational thread.
http://forums.tdiclub.com/showthread.php?t=7107&highlight=coolant+glow+plug
But the method suggested here did not work on my PD.
http://pics.tdiclub.com/data/500/coolant_glow_plugs.PNG
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