need help with revcounter driver

[andreina]

i install aftermarked engine ecu to turbo cars etc. my problem is getting the stock revcounter, toyota nissan to work properbly. when using multy coils. the ecu has a output for the revcounter but must be used with a electronic ignition module to convert it to a negative trigger and a ignition coil to operate properly,witch is not practical. if i put a 18w globe in the place of the ignition coil it only works on low rpm....can anyone please help. i need a circuit diagram i can built to drive the revcounter.........

 

[Mosaic]

Are u saying that the stock rev counter is driven from the inductive coil fly back pulse? Normally rev counters are driven by the ECU these days.

That would imply you are taking older model cars and upgrading to more modern power plants with the old dashboard displays.

With a multi coil ignition, wasted spark etc it's best to use the ecu feed. Drive the ecu feed thru a small step up transformer via a transistor switch. Feed the high voltage pulses to the old tacho.

 

[andreina]

hi Mosaic,im glad someone know what im talking about.what you saying is 100% what im doing.so the ecu feeds the transister switch which then changes the the ecu feed into a negative pulse into the primery side of the transformer which then will feed the tacho via the secondary side?sounds like it might work.you are genious.im gonna try it and give you feed back.thanks.