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TPS... zener diode, cross-over
- Subject: TPS... zener diode, cross-over
- From: Ben Barkow <dr.ben@xxxxxxxxx>
- Date: Sun, 30 Jan 2005 17:19:36 -0500
Since I am a digest reader, I'm sorry if my replies inadvertently neglect to
address some nominally earlier posts or if I depart from good thread format.
I understand Tom's point that the O2 sensor (AKA old-tyme narrow band
go/no-go device) takes control of the mixture to the extent that the ECU
changes strategies or maps, at least until there TPS activity resumes. But
since TPS tilting is advocated by many, it must do some good on some
machines towards making the system richer and hence more drivable. Even with
the O2 sensor mode in action closed loopwise, something must be directing
the injectors because the O2 sensor isn't up to the job (and the ECU O2
polling is far too slow) - can't be the barometer (only kidding) and, if I
were king, the TPS remains the most likely choice.
BTW, going back to modifying the TPS for better ax+b fuel tracking, a zener
diode (that's the "b") or some kind of regulated voltage standard might be
better than a passive resistor to model the intended relationship.
If somebody wanted to do some testing without damaging the stock bike too
much, can you buy male and female connectors for the TPS circuit?
Needless to emphasize, more heroic interventions from Techlusion or the chip
magicians go more to the root of the problem. And especially better to be
more heroic if you plan to replace the air filters since the stock ECU must,
I would guess (???), have only the barest ability to compensate for such
Interesting to learn from Andrew that a cross-over was included on some
(later?) bikes, as seems sensible to me - this is new for BMW but the bike
division are slow learners (of course, I can only speak for the last 38
years as a Beemer person). Also, depends on nationality this stuff about
carbon canisters, cat converters, muffler bearing grease fitting, etc.
For sure, the cross-over isn't active when synching with dual vacuum gauges
(my personal favorite tool for synching). I think grief often occurs if
folks neglect to pinch their cross-over tubes while working on the TBs.
And thanks for your solicitudiness inquiry, Andrew: yes, my test ports are
sealed when the dual vacuum gauges are off!
Well, gotta go over the bike store to pick-up my Uni foam filter universal
Ben... very cool this week
Ben Barkow, Toronto... 39 seasons on Beemers, 44 as a biker
1999 R1100S, 2004- Leo Vince exh, JetHot coatings, Ben's windscreen