anyone got an LM-1 with the RPM converter? I've got one for my XR2TT but the voltage pulse used for the RPM must not exceed 5v according to the manual. On mine the coil feed (i presume this is where you should take the pulse from to read the RPM) is 13v. How can I get around this? some sort of basic resistor circuit? Anyone else done it? I'm not too good with electrics/electronics. Or is there another point in the wiring that I can take it from that is below 5v?

Cheers in advance

 

no one?

 

give me 10 minutes and I will have a solution for you

 

SOLUTION 1

50/50 chance this will work.

If your car has an EDIS module, try connecting to PIN 3

EDIS is the ignition control module (BLACK and FLAT bolted to metal plate or body work)

This is the ignition control signal from the ecu that is at a 5 volt level.

(Double check you are on the right pin !!!!!!)

The pin numbers are marked on the edis connector on the module itself.
Should have 12 pins in total.

Depending on ecu software, this signal may be available on every spark
so acting like an rpm signal. On SOME cars this only gets updated when
the ignition advance changes.


SOLUTION 2 to follow...

 

SOLUTION 2

Build a pulse voltage limiter/regulator.

You will need the following components.

1) 1 x 4K7 resistor (0.25 watt) [order code 9463739 Have to buy many]

2) 1 x 5.1 volt zener diode (0.5 watt) [order code 3162412 have to buy 10 or more ]

Can get these online @ www.farnellinone.co.uk

Parts total should cost more than £1.50
Postage will cost MORE than parts and they have a minimum order price of £20

Could buy much cheaper elsewhere but I like online delivery they do



Resistor has no polarity. Label ends A and B.

Zener diode IS polarity sensitive.
The end with the black band/stripe is the POSITIVE, the other NEGATIVE.



1) Connect resistor end A to the coil negative. (Pulse input to our circuit)

2) Connect the NEGATIVE end of the zener diode to EARTH.

3) Connect resistor end B to zener diode POSITIVE and to the rev counter.


Thats it !!!


You do this at your own risk as if you make a mistake, its possible to
damage your new rev counter.

 

Hey Dan. Ive also got an RPM convertor, but have not rigged it up properly yet fro rpm. I've connected the MAP sensor to it, and that works fine.

Are u sure u cant use the ingition feed? Doesnt seem to make sense....

 

Just looked in the manual, says the voltage for aux inputs must not be more than 5v which is obvious. RPM is just a pulse.

 

Hi guys, sorry for leaving your replies un-appreciated - its one of those posts i do before a weekend, then by monday morning i've forgotten about it!!

anyway thanks for replies. I'll study them and probably be back soon with more questions!! lol. SECS, i dont think i have an EDIS module - the car is basically stock mk2 XR2 so still on simple dizzy with the little black amplifier module on top - unless this is what you mean?