Was going through a bucket of 1.8 L-jet parts and didn't recognize this one. Can someone tell me where I would see it, what is does, and how one might test it to make sure it works.

Went back to garage: It has full continuity cold, put it under a light bulb and reduced continuity to 0

Numbers: cant make out the part number, but these appear on it:
12V 40W / 2.75 / 13 degrees C, Bosh Germany / VW Audi ( logos)

First, I would study an L-Jet diagram and that should tell you what it might be.

Might be a thermo switch, but I do not recall off hand if L-Jet needs them like D-Jet does. As thermoswitches heat up it should close or open continuity depending on its design. If that is what it is, it might switch the cold start valve on/off dependent on temperature like D-Jet. I would test it by measuring the resistance on the two poles and heating it up and seeing what happens to the resistance or continuity.

I don't know what it is, but I can tell you where it is on an L jet bug, (L half of case, bakc of block, I know it is some sort of temp sensor)I will look in my Bentley when I get home, it has decent info on

It's the thermo-time switch for the cold start valve. The switch housing/bracket must be grounded. One teminal grounds the cold start valve below the specified temperture, the other powers a heater. The heater circuit and cold start valve get power while cranking, the heater open the injector ground after 5-8 seconds of cranking. In the diagram terminal 50 power comes in the top, ground is at the bottom, N17 is the cold start valve and F26 is the thermo-time switch.

The sensor was in a bucket of parts that came off an L-jet; where on my l-jet will I locate the part ?

It could have been in the bucket by mistake too...

on the L-jet system, its under the intake plenum,

b

OK- that's why I cant see it. Does the harness from the ECU plug into it ?

yep. its color coded, so since it looks like a brown plug, look for the brown ECU connector.

the cold start valve is blue plug and the AAR is black.

b

Then the sensor is controlling the opening of the cold start....Despite disconnecting the decel and ERG, I don't get a boost in rpms on cold mornings. Could this be a disconnected wire/ bad cold-sart valve, or defective harness.
Thanks for the info.

Thats because in CA, there are no COLD mornings.

well hold on a sec.


that sensor your holding controls the cold start valve, IE the fuel injector in the plenum that ONLY turns on when ambient temp is under 40F.

the AAR opens everytime, and on cold mornings, i do NOT see a change in RPMS, but rest assured the sensor and everything works....I know from experience that NOT having that valve working on a L-jet car sucks....

talk about rough during the cold!!!

b

We are expecting 39 tonight; I leave at 5:00am--oh boy!

Thanks again, I just learned a lot. Next weekend, I'll do some more probing and testing.Really appreciate hearing from another l-Jet owner

I love my L-jet system, rock solid reliability--i'm sure D-jet has the option to be just as reliable, but my system was trashed, and my engine was on its way out

b