Lotus Elan

Rev counter tachometer tach problems

PostPost by: dlbarnes1 » Fri Oct 09, 2009 4:45 pm

For the electronic ignition power, I connected to the input side of the fuse that is energized when the ignition is on (white wire). Wire size is 18 ga. I did not incorporate an inline fuse. Seems to me this circuit is in the same category as the ignition power to the coil.
Dave 72 Sprint DHC
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PostPost by: collins_dan » Fri Oct 09, 2009 7:03 pm

Thanks, I know exactly the wire you are referring to. I'll report back on the effect of the change.

Dan
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PostPost by: stuartgb100 » Sun Oct 11, 2009 12:13 pm

Whilst trying to fix my fuel starvation problem, I decided to take a break and
look at another issue - a mildy bouncing tach.

The recent addition of the Aldon module has exacerbated this problem.

I followed Rohan's advice earlier in this post and spent a half day in
rewiring the Aldon and the electronic rev limiter (giving them their own
dedicated supply).

It solved the problem, and the tacho is now almost perfect.

Thanks Rohan.

Regards,
Stuart.
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PostPost by: leifanten » Tue Oct 13, 2009 8:39 pm

Guys,
I found this useful article on the Allison/Crane optical ignition system that I have. It describes a way of fixing the rev counter that seems very simple. Has anyone tried it (It is on page 16 of the pdf)

http://69.20.53.62/pdf/90002000a.pdf

best
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PostPost by: dlbarnes1 » Wed Oct 14, 2009 9:59 pm

The description of modifying the tach is an interesting approach, although it seems simpler to me, on our Elans, to install a separate power supply wire to the electronic trigger.
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PostPost by: rgh0 » Thu Oct 15, 2009 10:37 am

I presume reducing the number of turnes from 2 to 1 is about reducing the sensitivity so the tach does not sense the smaller current pulses ( compared to the ignition coil current pulse) due to the electronics power supply being connected to the coil positive as shown in the wiring diagram.

As observed a simpler and better solution to just wire the electronics power supply to a different source

cheers
Rohan
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