Those sensors, even the dealer-sourced new ones, are good for a few
years in my experience.  They are unreliable enought to be worth keeping
a spare in the glove box.

neil n <musomuso@GMAIL.COM> writes:

> Hi all.
>
> On my Vanagon w/Jetta 2.0, I was having intermittent warm start
> problems that would cause engine to take 5+ cranking sessions to
> start. When started, it was sometimes rough, but would always feel
> "flooded" when trying to start it. Recently, it would also "hunt" at
> idle when restarted in hotter ambient temps. Being a DIY conversion,
> was concerned problem might be due to an intermittent wiring flaw or
> ?. Seems not.
>
> The suspect temp sensor bench tested out of spec mid range. This
> coincided with what I saw at coolant temp gauge when hard to start
> warm. In hindsight, this made total sense. The sensor was very likely
> telling the ECU to make the mix too fuel rich (Thanks Scott for the
> tip on that)
>
> Currently a used VW branded temp sensor is installed. No warm start
> problems so far, and no more error codes found in the OBD.
>
> Posting this as the ECU portion of sensor is basically the same as the
> ones used in the WBX engines. Also posting as I tested a new FLAPS
> "Standard" made in China sensor. Bought this as VW wanted $54 Cnd.,
> had to order it, and to my mind couldn't guarantee it would be OEM.
> Besides. Figured I'd test something I'd likely stand a better chance
> of finding out in the middle of nowhere.
>
> Results below. Seems the new sensor is close to out of spec mid-upper
> range. This might be due to my test methods though.
>
> Neil.
>
>
>      No Name             VW                           FLAPS "Standard" brand
>
> 21C  2900  Ohms       2300 Ohms             2500
> 27     2440                  1920                          2000
> 32     1940                  1550                          1600
> 38     1656                  1300                          1200
> 43     1360                  1070                            970
> 49     1130                    890                            780
> 54       932                    750                            620
> 60       780                    640                            510
> 66       666                    530                            420
> 71       555                    450                            350
> 77       470                    380                            290
> 82       400                    325                            247
> 88       337                    278                            222
> 93       286                    240                            215
> 100     217                    194                            204
>
> --
> Neil Nicholson '81 VanaJetta 2.0 "Jaco"
>
> http://tubaneil.googlepages.com/
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
>

--
1991 Vanagon GL