ttmott

iTrader: (1)

What does the TPS Narrow Range pot functionally do with respect to the engine's operations.

More specifically - what does the ECM do with the Narrow Range variable?

Thanks

arghx

iTrader: (3)

on the older rotaries which had only a plunger-style narrow range TPS, the TPS was especially used to control solenoids in the ACV. I presume it is similar in the FD. Extrapolating between the series 3/4 and the series 6 cars, the Narrow range signals would for example tell the ECU whether the throttle has been suddenly closed. When the throttle has been closed suddenly, the anti-afterburn function of the ISC solenoid is engaged. There are also a bunch of other idle-related emissions functions in the ACV that the narrow range TPS is used for.

ttmott

iTrader: (1)

Thanks that really helps -

My FD stalled a couple of times when comming to a stop (AC on); I thought possibly the narrow range was out of adjustment or the IAC is not reacting correctly; never really knew what all the narrow range TPS did. Seems the anti-afterburn is working correctly, however (smooth transition to idle).

I screwed the throttle stop dashpot in another turn and it seems to have helped the situation.

arghx - what tech manual did the page come from? My 95 manual has nothing like it; F20 is the intro to the OBD.....

Thanks again!

arghx

iTrader: (3)

the illustration is from the service highlights document in the sticky. The service highlights documents are incredibly valuable for understanding many aspects of how the engine works. I have service highlights from the series 3, series 4, and series 6 (from the sticky) cars as well as the series 2 (2009) Rx-8's if you are interested.

The narrow range TPS has its origins in the Bosch L jetronic and Motronic fuel injection systems used on 80s Porsches. Those cars had idle and WOT switches, with no 'real' TPS. Many of the functions of a full-range TPS (acceleration enrichment for example) were incorporated into the logathrmic voltage output curve of the flapper-type airflow meters that were common at the time.

the dashpot makes a huge difference in the decel stalling problem if it is adjusted correctly. You just have to adjust it a little at a time.