just installed celica c.o.p's and now no tach
 

i just finished installing celica cops in my BP+T MS1 v3.0 festiva and now my tach doesnt work. i wired it as per Lazzer408's diagram. its not a waste spark tach so i made a module as per a ms1 in a 323 gtx :

Attachment 188830

ive tried wiring it to the ms output to the coils the tach output terminals and the (1+4) wire and the (2+3) wire and neither way worked.


any thoughts?

you need a zener diode in that diagram to make it work, like this:

http://www.msextra.com/doc/ms1extra/...ev_Hivolts.GIF

1N5355B or a 1N5555B will work and are available at radioshack.

i bet you just need to give the tach output wire a 1K pullup from 12v.

that works too

How about making me a snazzy COP hold down clamp.

sure... ill charge way more money than its worth though... took me like 4 hours to make that damn thing...

ill try the the 1k ohm resister and see if it works. does it matter how many watts it is?

thanks for the replies

1/4watt works

the 1k ohm pull up didnt work... ill pick up a diode tomorrow and see if that fixes it

make sure its a ziener and make sure you put it with the stripe facing the over diodes like in the picture:



http://www.msextra.com/doc/ms1extra/...ev_Hivolts.GIF

could it have burned up my tach circuits running it without that extra diode?

no, unless they look damaged id try the ziener before 2nd guessing anything else

k...i didnt disconnect the tach circuits at first and i dont think they hurt the coils but it did cause a spark break up issue above 10psi... removed the wires and it revved smoothly to 14psi.

should i remove the 100k ohm resistors from around my diodes?

edit: what spark plugs should i use?

the diode thing didnt work at all... i tried both with and without the pull up and neither one makes the tach move at all. here is my crude little tester i made. i soldiered all the connections together and to the corresponding wires on the car.

Attachment 188787

that looks nothing like the zeiner diode i used..

and with the zeiner you do not need the pull up resistor

do you hve cops on your 323? caue it worked fine on my miata coil packs hooked up to the coil driver wires coming out of the igniter

I had KLg4 coils on my 323 on the KL and used the same diagram as post earlier by me.

the ziener diode i used from RS was this:

http://www.radioshack.com/product/in...uctId=2049725#

does the one in that link replace the 1n4004 or the 1n5355B?

the 1n5355B is a ziener..

on your diagram it appears you attached the 1n4004s to the tach input? should be the spark outputs from the MS.

oh... i put them on the tach output terminals of the coils