Speedometer Issue

[318isbmw]

I just purchased an 86 325e that had been swapped with an s50 by the previous owner.

The speedo is off by quite a bit (about 15mph). I know that with the swap you've gotta mess with the speedo sensor on an early car. He had swapped the gauge cluster for a 325i cluster. Any chance that this is causing the issue, or suggestions on where I should start?

Also, it looks like the tach is off by ~250 rpm's as well. At idle, which on the motor you can tell by the sound it's not under load the gauge shows 1000 rpm's, so it seems both are off, but the speedo is much more significant. I'll also throw in there that I've got experience with swapped cars, my old daily driver was m50 swapped, so that's my reason for the confidence about the idle.

Also I'll note it's on 195/65/14's so it's not just a tire size difference.

[caesar101]

I know my rpms read low by 200 because the needle was not installed correctly. Is it sitting against the stop? You really need something to read the RPM output from the DME so you have a good number to compare to.

[318isbmw]

Thanks for the heads up, that gets me thinking about the speedometer as well since the previous owner had colored the needles. I just checked and yes it is against the stop.