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RPM not working after COP conversion

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I just converted the old distributor type ignition to COP using Toyota 1NZ coils in St205 3sgte Mr2 .

Now the problem is i am logging RPM but the RPM meter is not working.

tech @ link says we need to talk to a specialist dash electrician to sort this out.

Any suggestions ?

Is the tachometer controlled via the ecu or the factory igniter?

I would assume you have changed the igniter to a 4 channel to control the COP and now have eliminated the tacho control which is labelled EXT on the underside of the original igniter.

My suggestion would be to wire the tacho through the Link and use that instead. If the tacho used to run off the coil negative instead of the igniter then you may need to add a pull up resistor or a signal converter to get it to operate correctly.

I think in your case, you need to wire up a tacho relay/converter. Your tach in there singnals on coil negative, new outputs use a pulse.


Another alternative, is to get the Dakota tach box shown here http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=127/prd127.htm

I have used the above Dakota box with good results.

good luck!


Thanks for the fast reply.. Yes tacho was controlled by the factory ignitior.

Does models like Belta, Corolla or Axio have signal converters that might become handy in this case ?


Yes sir. I did the COP conversion because i was not getting the spark needed at Launch Control and under boost. This solved my problem and i felt significant improvement.

This is what i was able to achieve


You should be able to control it from the link if it was originally controlled via the igniter. I have done this a few times when converting to cop on Toyota motors. I believe the ext wire from the igniter is not connected to the coil negative and is actually switched via the Input to the igniter from the Ecu.

Wire one of your aux outputs to your tacho and after you set it up it should work.


Since i have not done this before. I am facing another issue.

1. When i set the distributor to 10 Degree before TDC the car hits limiter fine , launch control gets active , pops and bangs and the world is happy but car runs like crap as if it is running super retarded.

2. When i center align the distributor the car runs good and you can feel the power but NO HARD LIMITERS and LAUNCH CONTROL doesnt work, no POPS n BANGS.

I was facing this scenario when i didnt do the COP conversion.

NOTE : There were no miss fires.

Logged Ignition timing and the timing in the map is identical.

Do i need to change the Dwell times ?

Attaching the PCL and log files so that you can take a better look.

First 2 logs are when distributor is set at 10 deg BTDC

3rd log is when it is center alligned.

Attached Files
  • Log-2016-09-8-10-40-13-pm-timing-retard1.llg
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

  • Log-2016-09-8-10-48-35-pm-timing-retard-log-2.llg
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

  • Log-2016-09-8-11-46-36-pm-after-distributor-set-up-to-center.llg
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

  • st205cop.pclr
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.


When you say you'removing the distributor, are you resetting the base ignition timing in the ECU each time?

If you're moving the distributor but not resetting the base ignition timing then that will do exactly what you are saying.

If you're to retarded then it will feel flat and make a lot of pops and bangs out the exhaust due to the heat generated from retarded timing and also the launch control will be more aggressive and loud due to actually firing even further ATDC.

Then when you move it back again it will be more advanced so go better but less aggressive on the launch control due to timing not being as retarded.

The ignition table and angle in the log will match (providing there is not corrections from iat etc) even if the base ignition timing if out.

Hi Chris,

yes i was thinking along the same line. I am using firmware but i cant seem to find the table to lock base ignition timing table.

I have just checked it offline mode.

Can you please confirm that ?

Setting the base timing is under



Then click the little spanner and this will lock the timing to what ever you enter in there.


Locked the timing at distributor , locked it in the ECU at 10 btdc

checked after a while timing shows 15 -18

Process repeated but no success.

Reviving an old thread. Is it acceptable to use the coil in a relay as a replacement for the ignition coil to trigger a high drive tacho? I have taken the latching mechanism out of the relay. I am driving the relay via aux output. I have the dash tacho on the same connector on the relay and it works when I tested it.

Will this damage anything?


A lot of people do the same or similar to generate a tach signal for older dashes.

We usually reply within 12hrs (often sooner)

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