Tach cuts out at 3000rpm - MJLJ ver3

sandersk · Post by **sandersk** » Mon Oct 10, 2005 8:22 pm

I'm running straight from the Tach output on new MJLJ Ver 3, works ok up to around 3000rpm then tach just cuts out.
Thought I'd seen something similar on this forum before but can't find it. Does anyone have any suggestions for simple circuit to fix this?

P.S. the voltage output from MJ Tach pin is approx 2v less than the reading with dizzy setup - do I simply need something to boost this?

Thanks,
Keith

Josh_b · Post by **Josh_b** » Mon Oct 10, 2005 10:50 pm

the tach cutting out above 3000 was caused by the voltage being to high when using the diode adapter circuit, what volts does it show at 3000?

sandersk · Post by **sandersk** » Tue Oct 11, 2005 11:57 am

The readings are as follows (taken with digital voltmeter on 20v dc scale)

Tickover - 12.8v
1500rpm - 12.4v
2000rpm - 12.25v
2500rpm - 12.2v
2700rpm - 12.18v (this is the point when tach cuts out)

I haven't taken detailed readings from old dizzy setup but was similar pattern but starting at around 14.2/14.5v on tickover.

Keith S.