Tachometer troubles

[miniminor63]

Hi

I have an elliot tachometer for a 4 cylinder engine (which mine is). I have previously used it with a coil and with megajolt. On the megajolt I used it directly connected to the ford edis module.

I have installed a pullup resistor on the vems and have connected the tacho to the output I soldered that to, (typically channel 0 right?) still the tacho goes straight to max as I crank the engine. What could this be?

Divider is set to 0, could that be the issue?

[rob@vems.co.uk]

I've always used divider set to 16 with good results.

[miniminor63]

that worked! thanks!

[Tony C]

sorry to bring this post up again,
but need some advice,
the rev counter seems to be working ok, (rover sd1 v8 lucas one)
but now we can open the car up on the throttle and give her a LOT more revs the tach seems to read higher than the vems tac as the rpm increases,
any ideas how to change this??
the divider is set to 18 as that gives the correct rpm at idle etc.

also is there any way that the vems can do a test signal for the tacho?
may make setting up tachos easier in the future without having to run the engine, i tried the soundwave file on the trigger input, but the tach jumps around as rpm increases and cant get a true 100% reading
reason i ask on my old mallory cdi ignition there was a tacho test feature, which when turned on gave a reading at 3k which you checked to see if the tacho read the same so you know it was calibrated to the cdi box,

[mattias]

TonyC : Only the latest firmwares have accurate tacho output, use 1.1.74 for the new improved functionality.

[Tony C]

wish i had left alone,
upgrading to this firmware has given me all sorts of head aches :-(

[Sprocket]

Tony, with respect, you need to spend just as much time and attention to the set up, configuration and tuning of the ECU as you do with the engine itself. I spent two weeks on my first attempt to get the Mini running with Vems, and likely another two eeks messing around with the tune, not to mention the 2.5 hours on the dyno.

It sounds like there may still be a few gremlins in you set up, even though you are up and running on 1.1.44. Believe me, 1.1.44 is far better than 1.0.73 in many respects, but 1.1.74 is far better than 1.1.44. You need to spend the time working through the problems.

If you really need a running car and don't have the time to mess with it, don't mess with it, even though it desperately needs upgrading.

I would personaly use a tacho that works direct from the coil, where possible. I know Rover used this method.

Just trying to help, as I feel your frustration, and it reminds me of my beginings