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RPM signal

Posted: Tue Jan 16, 2007 8:33 pm
by jayw
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.

Posted: Tue Jan 16, 2007 8:36 pm
by tim leech
I dunno but i know its a common fault for them to read slowly, mine does!

Posted: Tue Jan 16, 2007 8:45 pm
by jayw
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

Posted: Tue Jan 16, 2007 8:55 pm
by Anonymous
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 !!!

Posted: Tue Jan 16, 2007 8:57 pm
by Vanny
BX has a distributor :( and as best i know the rev counter is driven by the ECU

Posted: Tue Jan 16, 2007 10:34 pm
by thanuttiscotsman
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

Posted: Tue Jan 16, 2007 11:03 pm
by ollie
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!

Posted: Tue Jan 16, 2007 11:47 pm
by Mike E (uk)
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

Posted: Tue Jan 16, 2007 11:59 pm
by kriskarrera
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.

Posted: Wed Jan 17, 2007 8:35 am
by Mandic
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

revs

Posted: Sun Jan 28, 2007 1:26 pm
by Toddman
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? :D

Cheers
Luke