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Old 04-30-2012, 04:51 AM   #47 (permalink)
nickdigger
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Quote:
Originally Posted by nickdigger View Post
Did anyone ever successfully find where to tap the MPGuino into a TDI? I.e., anyone besides yetimus & others who were lucky enough to have a Fuel Consumption signal from their ECU. My 98 A3 TDI doesn't have that signal (harness is missing that wire), and i assume only some Passats actually had it.
Quick answer for you, nick:

Add a wire to your T68 ecu harness connector, at pin #9. I recommend you de-pin one from a junk yard harness, and add it to yours. (Note: depinning VW harnesses is a b-word). Now run it through a rubber plug in the firewall, near the fuse block. You'll need to remove the 100k resistor from your mpguino, because the signal is low-voltage and does not need to be pulled down. Keep the zener, though.

Next, get your VSS signal from the blue/white (or white/blue) wire at W/1 on the fuse/junction block. It's a 12v-0v signal, so keep the corresponding 100k resistor on the 'guino.

Set your InjTrg to 1 (Rising). As for other settings, i haven't calibrated mine yet. My ballpark guess is around 13000 VSS/mile, and 170,000,000 usec/gal, with maybe a 100 usec InjDelay. But i wont know until after i've burned a few tanks.

Good luck.

P.S. kick yourself for not following through with this 2 years ago.
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