This is mostly directed at JasonC, but any and all responses are welcome. My car is currently about 800 miles from where I am. They guy working on it is, at my request, trying to implement TPS-based boost (Less throttle = lower boost target. More throttle = higher boost target.) on a TEC ECU (TEC-GT if it matters.)
Here's what he's reporting: "I am trying to get the TPS-based boost working nicely. Initial problem was that the TPS read a minimum of .52V closed and 3.55V open. The way it works is to hook the TPS up to a GPI channel on the TEC (already done) and then use that channel to trim the boost duty cycle map. The way the trim works, however, is that anything from 0-2.5V will reduce our duty cycle by up to 50%, anything from 2.5-5V will increase it by up to 50%... so I need to get the TPS to read closer to 5V at WOT. The 99+ cars have a three wire non-adjustable TPS, so from the factory, where it is is where it is. I have explored a couple of different options. An adjustable 94-97 will not work because it is a four wire." and "One solution would be to physically rotate the TPS to where it will read higher voltage per throttle input, and drill and tap the throttle body for the new base setting. This is not a perfect scenario; once screw would solidly mount to the throttle body, the other would be used with a little fabricated bracket to make sure the TPS physically stays on the throttle body. However it would result in the numbers we are looking for with no electrical gizmo action (WOT reads 4.88V)" and "The GPO trim function is set up in the firmware, there is no way to change how it responds to the voltage... so anything below 2.5v will decrease duty cycle, and anything above increases. You can't change the negative/positive value set point, 2.5 is the magic number." The car is a '99. My question are these: 1) Does this sound right to you? 1a) The stock TPS doesn't read 0-5V? 1b) The TEC doesn't support "mapping" or even "offset and scale" an input voltage? 1c) None of the TEC's input/output map function coudld be used to accomplish this? 2) How did you implement TPS-boost on your car? 2a) Is the boost signal taken from before or after the throttle plate? (I would prefer to take it separate from from before the throttle plate in order to minimize backpressure and inefficiency at smaller throttle openings..) 2b) Any problems with reliability or resolution? Thanks in advance, M. _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
