How long does your GP relay post-glow or after-glow?

TylerDurden · Post by **TylerDurden** » Mon Oct 22, 2012 12:33 pm

I mean after the engine has started.

I plugged a spare GP relay into my Dasher and added an LED to monitor glow-time... as described somewhere, my glow system stays energized about 180sec. ( Even with temp sensor wire grounded, initial glow <5sec.)

Relay: BOSCH 0 281 003 099

Anyone else have similar results?

CarlosA · Post by **CarlosA** » Mon Oct 22, 2012 11:33 pm

I`m going to test mine out tomorrow when its like 40 degrees out. I have also been wondering about this as my previous car was on a toggle switch and this one starts easier and idles smoother probably because of the "post glow".

TylerDurden · Post by **TylerDurden** » Thu Oct 25, 2012 6:36 pm

I put a 50A strip fuse in the holder, to replace the wire bridge the PO had installed. A couple of tests revealed enough resistance in the connections to melt the fuse holder, but not blow the fuse.

I cleaned the connections, washers and fuse tabs to a sheen and tested again... a 3min post-glow gets the fuse terminals up to about 200F.

The post-glow does not get any shorter after the engine is up to temperature, so maybe the relay has to be replaced. I enjoy the smooth start and warmup, but the 3min glow every time I restart is not inspiring confidence.

air-cooled or diesel · Thu Oct 25, 2012 8:06 pm

i know there is some 'post glow' to make sure motor runs during cold start, a few second sounds right not minutes.

the man 53 · Post by **the man 53** » Fri Oct 26, 2012 7:08 am

From what I have read the long style GP had little to no after glow with that relay. The fast glow ones had a short time of afterglow from what I have read. The later ones stayed on up to 2 minutes. I don't have any info to link but I remember many discussions about this and I think this was the end result.

TylerDurden · Post by **TylerDurden** » Fri Oct 26, 2012 10:31 am

Yeah, I scoured the webz on the subject and it seems the longer post-glow is common on the TDIs, which may use PWM to drop the voltage during post-glow.

So far, it seems the GPs are handling the extended cycle, but the effect on their lifespan (and the entire circuit) is an open question.

Dakotakid · Post by **Dakotakid** » Fri Oct 26, 2012 2:07 pm

I think vince Waldonmeister discussed this many years ago.
Try searching through his ramblings.

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