Tachometer Pulses per Revolution (200tdi)

[chadler]

Grateful is anyone knows about the output pulses from a 200tdi A127-45 alternator that can help me.

I've installed a Madman EMS3 engine monitor, which can function as a tachometer. I have connected it to the W terminal on the alternator and it is reading but needs calibrating- there are calibration settings in the menu of the EMS3 but I need to know how many pulses per revolution to set in order to get the correct read out on the rev counter... Any ideas?

Here's the manual for the device: https://www.madmandevelopments.com/wp-content/uploads/2021/03/EMS3-v1_04.pdf

 

Thanks in advance knowledgeable people

[Bowie69]

It's tricky, because it depends on pulley size (alternator runs faster than the crank normally) so pulses per rev is not really easily done.

Suggest you follow the instructions that says to use a handheld tach to determine the engine speed and then set it up accordingly.

Or, with it idling, set it to ~ 700rpm on the gauge, or if you are feeling adventurous and want more resolution then you can stick the engine on the rev limiter (4K, IIRC?) and then see what it reads and readjust.

[Maverik]

2 hours ago, chadler said:

Grateful is anyone knows about the output pulses from a 200tdi A127-45 alternator that can help me.

I've installed a Madman EMS3 engine monitor, which can function as a tachometer. I have connected it to the W terminal on the alternator and it is reading but needs calibrating- there are calibration settings in the menu of the EMS3 but I need to know how many pulses per revolution to set in order to get the correct read out on the rev counter... Any ideas?

Here's the manual for the device: https://www.madmandevelopments.com/wp-content/uploads/2021/03/EMS3-v1_04.pdf

 

Thanks in advance knowledgeable people

When I set up my rev Tacho I bought a cheap later rev measure from ebay, used it a number of times now and its a great bot of kit.

Handheld Digital Laser Rev Counter DT2234C Meter Non Contact Optical Tachometer | eBay

[Bowie69]

TBH, I have the same, very useful for all sorts.

[chadler]

Thanks both. I've set the pulses/rev to where it displays 700 at idle and have ordered one of those handheld tachos; will fine tune the pulses until it matches exactly when it arrives

[Arjan]

Thanks - not seen these IR Tacho's before.

[western]

750 to 850 is idle rpm for a 200tdi.

[chadler]

23 hours ago, western said:

750 to 850 is idle rpm for a 200tdi.

The genuine discovery WSM I have quotes 720 +/- 20 rpm as the 200tdi idle speed?

[western]

Defender manual info below

 

[chadler]

Thanks again all. Just to round this thread off:

I purchased the handheld tacho as suggested. Very simple operation: just attach some of the supplied reflective tape to the crank pulley and shine the laser pointer at it. Initial idle speed was approx 700 which according to Western's photo above is too low for a Defender 200tdi (never knew there was a difference between Disco and Defender).

Idle speed adjusted up using the thumb-wheel on the throttle cable as it enters the fuel injection pump to 790rpm and the EMS-3 needs to be calibrated at 14.7 pulses per revolution to read correctly.

Edited April 24, 2023 by chadler