Tacho issue - shows 2,200 rpm on idle

[Zibsnis]

Hi everyone,
Would appreciate your help on the following - had a faulty tacho on e9, bought another unit on ebay, installed but for some reason on idle speed tacho shows about 2,200 rpm despite it shall be less than 1,000 ... Tacho should be correct one with the same oem #, supposed for 6zyl4tact engine that is the one I got (stock 3.0 swapped with 3.5 m30b35). Getrag was also swapped from 3-speed auto trans to 5-speed Getrag 265 with overdive.
What could be wrong here and have I missed smth?
Thanks in advance! Uldis

 

[Thomas76]

Looks like it's double, suggesting it's either counting twice or receiving double from ignition.
Something unique about your engine swap?

 

[Dick Steinkamp]

Looks like it's double, suggesting it's either counting twice or receiving double from ignition.
Something unique about your engine swap?

M70 swap?

 

[Zibsnis]

Good point, wil

Looks like it's double, suggesting it's either counting twice or receiving double from ignition.
Something unique about your engine swap

Good point, will check this with the shop. We have repalced stock ECU with Vems as well and might happen some wiring sending data went wrong.

 

[Wes]

Same fault on both gauges, or different issues?

 

[Zibsnis]

Same fault on both gauges, or different issues?

Different. The old one did not show any signs of life at all.

 

[Arde]

Different. The old one did not show any signs of life at all.

Oh, so the average between the old and the new is correct ...