tach does not read correct

[stew jones]

i have a very odd system in a 72 jaguar v12 e type. it has jenvy injection crank trigger ign and inj. i use a motec m600 management system with duel toyota 6cyl way spark coil packs. every thing is great with the unit performance wise. i have gotten the tach to work but it reads about 1100 over actual rpm. fyi the tach has been sent out and converted to the toyota way spark. any idea what would cause this and or how to fix it? thank you in advance.

[Martin]

You can change the calibration of the Tacho output on your M600


Adjust>TAcho output(whichever one you are using)>Parameters>Calibration


The help on the right of it explains it all. Hope you get it right


Cheers

[stew jones]

thanks for the advise....however in the help menu it said '' no further help on this item''....any other ideas? cal value is set at 0.0 and start x10 is set at 0. i have tryed setting the cal with the car running and when pressing enter to set it the car instantly shuts down.

[Martin]

I didnt mean the F1 help, the extra info on the right hand side of where you enter the selection.


Strange that it shuts down? Did you RESET the ECU? If you change the calibration you can get it right.

Remember, this can only fix it if the error is constant with a certain factor. i.e. At 2000, it reads 2200, at 4000 4400, then you can fix it with calibration.

[stew jones]

i was usin the one on the right. and thats the message i got. the tach read 2100 at a actual idle of 1000 on the manager. since its to high i tryed to enter a value o -0.5 to see if that would drop it...but it kicked it out stating it was out of range and set it back to 0.0 do you think is is an issue with the duel toyota ign? since the tach reads about twice the actual rpm

[MarkMc]

Do you know how many pulses per rev the tacho should have? Or exactly what has been modified? The tacho output does exaclty what is says so you need to match this with the actual tacho.

If you have 0.0 set for a V12 it will give you 6 pulses per revolution (one per spark) of the crank, if the tacho is too high (double) with this setting you need to set 3.0 which is only three pulses per rev. There is more or less two modes depending on the number you put.

How do you have the ECU set up? is it set as a six cylinder two stroke or as 612 (number of cylinders)? Either way it will still be six sparks per crank rev.

If the engine is stopping I am assuming you are pressing "R" for reset when you make your changes? This resets the ECU which means for a brief instant it is not running the engine, depending on the actual engine some engines can't "free wheel" for long and stop, some engines are ok and you just get a slight cough and away it goes again, this is normal.