RPM signal

jayw · Post by **jayw** » Tue Jan 16, 2007 8:33 pm

Anyone know what signal feeds the Rev counter on our cars? I'm looking for something like a 5-12v square wave signal?

If it's relevent it's the ML4.1

Cheers.

tim leech · Post by **tim leech** » Tue Jan 16, 2007 8:36 pm

I dunno but i know its a common fault for them to read slowly, mine does!

jayw · Post by **jayw** » Tue Jan 16, 2007 8:45 pm

Need to know so i can see if i need an adapter for the progressive controller for my Nitrous.

The controller only works on the signal type above or i need the converter thingy

Anonymous · Post by **Anonymous** » Tue Jan 16, 2007 8:55 pm

i know the zx pulse comes from the ecu and is basically picked up from the crank sensor but you should be a ble to pick up a rev from your coil pack or does the bx stil use a distributer? if it does then i'm talking sh*t cos it would mean yours is totally different !!!

Post by **Vanny** » Tue Jan 16, 2007 8:57 pm

BX has a distributor

and as best i know the rev counter is driven by the ECU

thanuttiscotsman · Post by **thanuttiscotsman** » Tue Jan 16, 2007 10:34 pm

hi there,
it doesnt come form the ecu, the signal is direct from the ign coil. if you trace it from the ign coil back it will be the only one that heads to the bulkhead. the others are the ign module wire and the power supply to the coil. it is common for the rev counter wire to break or get corroded at the connector near to the bulkhead.

cheers rossco

ollie · Post by **ollie** » Tue Jan 16, 2007 11:03 pm

It does indeed, its not even directly connested to the ign amp, part of the fabulous "fit all model type" multi plugs by the gearbox mount!

Mike E (uk) · Post by **Mike E (uk)** » Tue Jan 16, 2007 11:47 pm

The LT end of the coil will have a square wave between about 0 and 12V,

This will feed the analogue rev counter, which is probably inaccurate.

Mike

kriskarrera · Post by **kriskarrera** » Tue Jan 16, 2007 11:59 pm

Vanny wrote:BX has a distributor and as best i know the rev counter is driven by the ECU

Eh? Has a cap yes but not a distributor for timing like the jetronic engines.

Mandic · Post by **Mandic** » Wed Jan 17, 2007 8:35 am

I forgot which exact wire is it, as it's a long time since I was installing e-manage on my ECU, but You can check Haynes, at the end of the manual there are wiring diagrams. Then You just check which # the wire is, go and unmount ECU and see which wire is it exactly.

Cheers

Ziga

Post by **Toddman** » Sun Jan 28, 2007 1:26 pm

AFAIK ir is indeed taken directly from the coil.

If you want to be picky the BX 16v does have a distributor but it is a breakerless one.
If you don't have a dizzy how can you have a dizzy cap?

Cheers
Luke

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