View single post by Rick in Miami
 Posted: 09-18-2018 12:53 pm
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Rick in Miami

 

Joined: 02-17-2015
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 Don – I would try taking the taking the JH tachometer out of the equation by bypassing it. Power to the coil goes through it and the RVI just does not play well with electronic ignitions. If that eliminates your miss then you will probably need to convert your RVI (impulse) tach to (or replace with) an RVC tach (current).

When I converted to a Pertronix II my tach would hardly work at all. I tried several wiring alternatives to supply switched 12v to directly the coil while also keeping the RVI tach connected but the best results I could achieve was accuracy up to 3000 RPM. After 3000 it was worthless. I replaced with the RVC and now all is good.

Some background info may be found here https://www.tscusa.org/tech/4_RVI_to_RVC_Tach_Conversion_PhilipMillward_StagNews_2016_Q3_Summer.pdf

I would also recommend making sure the idle circuit on your Dellortos is clean and jetted correctly for your engine upgrades. Are they properly balanced? Are your progression holes properly closed at idle? Are the floats set to the correct height? Mixture screws evenly adjusted?

Some more background info is available here
https://www.mazdabg.com/ftp-uploads/Mazda/RX7/info/carb_book.pdf

Hope this helps.

Rick