VanagonSuby Posted February 5, 2019 Share Posted February 5, 2019 I have a 1993 EJ22 in my VW van, and recently have been experiencing common TPS failure symptoms (low idle ~200 rpm when warm, bucking/jerking at around 2,000 rpm, when engine cold it will start then die a few seconds later, hunting idle). No check engine light. I tested the sensor this morning. Voltage is ok. But testing the resistance between pins 2 and 4, I get 9.8 K ohms when fully closed and 1.7 K ohms when WOT. The shop manual says this test should reveal 1 K ohms when fully closed and 4.3 K ohms fully open, with resistance increasing as throttle opens. Mine is the opposite, dropping as the throttle opens. The values, obviously, are out of spec. Safe to say the sensor is bad? Should I be doing something else? Link to comment Share on other sites More sharing options...
RumbleRumble Posted February 6, 2019 Share Posted February 6, 2019 Vacuum leak? IACV could be really dirty or just bad, but your sensor is reading incorrect. Link to comment Share on other sites More sharing options...
Tronic Posted February 7, 2019 Share Posted February 7, 2019 More likely an air flow metering problem ? that said the old TPS just plain wear out mechanically and the resistance can jump all over the place. I would be looking for dead spots like sudden open circuit in the TPS as it turns not absolute resistances. The resistance doesn't matter that much if its just picking off a Voltage on the wiper.i.e the circuit its connected to is not looking at the resistance, its looking at the Voltage, or portion of the Voltage if you have say 5V or 12V across the TPS. Not sure what technology Subaru had in 1993 in the air intake, my old 1990 Toyota has a big flapper vane connected to get another variable resistor. Did they then move to some hot air or optical set-ups like that ? Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.