Some of the things wrong with my existing/previous TPS’s were:
- They wore out very quickly; being just variable resistors, constant movement around the idle and cruise portion of the track caused premature wear. This caused problems with MS.
- They constantly needed re-calibrating in MegaSquirt. Repeatability was poor. After a day or even less I had to re-calibrate.
I have been looking for a while for non-contact TPS’s, utilising Hall Effect technology, but TPS’s that I did find were very expensive and/or not available locally here in Australia. Another issue is if I continue to use the SU carb as my throttle body (very likely) I have to use the same style as my current TPS.
All I knew about my current TPS was that it is standard fitment on many GM vehicles including the local GMH 3.8L VS, VT, VX, VY, WH, WK, V6 Holden Commodore’s and some Daewoo’s. I stumbled upon Wells Vehicle Electronics web site and discovered that they had the same part TPS112 and also they made brief mention that they also made non-contact versions! A brief online chat with a sales rep gleamed that all new TPS112’s were of the non-contact variety!
All the retailers that I could find in the US either didn’t know if their stock was the newer no-contact technology or they didn’t ship to Australia. Did a quick search on EBay, and presto found a local supplier Eagle Auto Parts that listed a Wells TP112 for AU $92.00. I guessed at that price it must be one of the new parts, as a standard no name brand goes for around AU $27.00, or at least I hoped!
Anyway, it arrived today, and a quick check with a multimeter confirmed that it was not a simple resistive TPS. I then connected it up to a 5V power supply and monitored the output with a CRO. Perfect, nice and smooth!
Below is a picture along with the pin outs and MS Wire colours.