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Tach Help Needed on BMW LSA Swap
Guys I need some help with a tach situation on my BMW 540 with an Gen IV 58x LSA supercharged engine swap running a GMPP E67 computer. The car originally had a V8 motor, but its a BMW and crap gets weird with programming. I can reprogram my instrument cluster to receive analog signal for the Tach, water temp, Oil Pressure etc.. Most of the BMW forums where folks have done am LS swap say to program the cluster to 4 Cylinder and to look for 2 pulses per revolution as that is what the ECU is sending. Problem is, in my M5 Cluster I don't have the option to program the tach to look for 2_PPR. I can program the cluster/Tach to look for 3_PPR or 4_PPR, 4 Cyl, 6 Cyl, 8 Cyl, 12 Cyl
I was looking at an older HPT post about the tach output settings. Ive attached screenshots of the tach output in my HPtuners screen as well as a screen for my PASoft coding software for the BMW. I tried making a couple changes to HPT and upload the file to the ECU but I have noticed no change in tach operation in my cluster. At idle my Tach shows about 600 rpm, when the idle is actually 900 in HPT. It progressively gets further and further off the higher the RPM's go. I currently have my cluster programmed to 4 Cyl and 3_PPR. Wondering if I change it to 6 Cyl and 4_PPR in my cluster and then make a change to the tach output in HPT if I can make any difference in the physical cluster tach operation.
I'm learning HPTuners as I work thru this project and don't understand the capabilities of the Tach Output screen and what I can change to make the BMW cluster see 3 or 4 PPR, since the GM ECU is sending 2 PPR, or if this is even possible.
Below is the thread I was referencing
https://forum.hptuners.com/showthrea...der-tachometer
The car hasn't been to the dyno tuner yet, as I'm still trying to get things finalized in the dash. I want the tach as close as possible. The car runs and drives like a banshee with a safe tune for the setup. Here is the car
https://youtu.be/05Xslfvn5zQ
