Recalibrate tach

[jink0619]

Tach is off on my s54swappes m3, it's off by 600 or so, car idles around 1200k, I'm running a 2.93diff and 17"wheels. Does anyone know how to recalibrate the tach to be accurate with the s54?

[jink0619]

I'm running a ZF320 Trans and 2.93 diff and this is in 5th gear

[nando]

you need the coding plug from an E28 M5. I think there's a euro car that's more common that you can use as well. the problem is you're using a regular 6 cylinder coding plug on an M3 tach, the regular 6 cylinder tach only goes to 7000rpm. or maybe you even still have the S14 coding plug in there..

[jink0619]

Thanks for the response Nando, I do still have the s14 coding plug in and tach revs to 8k but in my case it's alil more. I probably will have circuit board rebuilt cause coolant gauge is acting up also.

[nando]

Yeah, you definitely need a different coding plug.

[Northern]

Coolant gauge could just be a loose/dirty ground nut on the gauge. That's cheaper and faster to check for than sending the cluster out.