Autometer tach question

[crusty_shadow]

I finally got my engine up and running this week- fired up and ran on the first shot no less. everything is going pretty well but I do have an issue that I cant seem to figure out on my own.
I am running a 2.2 Chrysler with MS3 and the MS3X card, 36-1 wheel LS2 truck coils in full sequential mode- no wasted spark, coil near plug.
I have an autometer 5" tach and im using the MS3X tacho out to drive the tach. it does work but its not showing the same RPM as what is displayed in TS. when driving the tack at full speed it is about 300 rpm more than what TS is showing, and when I run the tach at half speed it is about 300 rpm less than what TS is showing. I do have the tach in 4cyl mode- brown and orange jumpers on the tach are cut.
has anyone else run into this problem and been able to come up with solution?

[crusty_shadow]

added my .msq

so no one has anything? I searched all over this forum and all the issues ive seen were autometer tachs that didn't work at all. I have signal and the tach does work but the rpms are not correct.

any suggestions?

[jsmcortina]

Sounds like a problem with the tacho itself ?

James

[crusty_shadow]

im not sure, I don't have another vehicle that I can hook the tach up to to verify operation. in the instructions it has a small chart under the calibration section that says "typical engine pulses per revolution- 4cyl- 2 pulse, 6 cyl - 3 pulse, 8 cyl-4 pulse". im wondering if I set the tach for 8 cyl, then drive it at half speed from the MS that I would get the correct rpm reading. i'll have to try this tomorrow and I may see if one of my neighbors will let me hook the tach up to their car that has a conventional distributor and single ignition coil to see that it works correctly.

[Matt Cramer]

Is there any sort of adjustment / calibration pot on the tach somewhere?