Toyota COPs and AEM EMS
 

So I have a 1990 ignition system on my car, and would like to convert it to the Toyota coil on plugs (I have a full set). What settings do I need to change on the AEM EMS to accommodate the new ignition?

Thanks!

Below is the setup for '99~'05.

For <99, the ignition phasing teeth 1 to 4 need to be re-arranged.

http://forum.miata.net/vb/attachment...1&d=1255885917

Try this for 90~92 and non CA 93 ign phasing with COPs.
Don't forget to do ignition fine adjust to get the correct timing (which adjusts "Ignition Sync" teeth). Set it to all 10°. Adjust Pickup Delay Comp so that the timing at 4000-5000 RPM is the same as at idle.


Be sure to go to Options->Coil and turn on coils 1~4 and turn off 5~10.

I suppose I just wire it as it was posted in the COP thread for doing the conversion with a stock ecu(someone did a diagram on page 6 or 7).

By the way, thanks for the replies.

Jason; I don't think I set any of these when I converted to Toyota COPS. Would a 96 be any different than a 99?

Thanks

Are you going to run the COPs in sequential or batch fire like the OEM ECU? I think the wiring diagrams in the COP thread are for batch fire setups, at least they were the last time I read thru that thread, other than maybe tweaking the dwell curve. I posted my sequential AEM EMS settings for my '92 car when running the toyota COPS here I'd say less than a year ago. I'm pretty ---- with wiring but still swapped a few wires and ran my ignition backwards for a few hours. Fortunately nothing got damaged to my knowledge (maybe I do have some bend rods!), but definitely made a lot of very bad bad bad noises and blew off my boost gauge lines a few times backfiring out the intake.

Here's the post with a screenshot of my sequential settings. The ignition teeth still seem off 180 cam deg's but it runs like that so whatever.

https://www.miataturbo.net/forum/t28029/

Yes. To convert a 96 to COPs the only changes are to correct the dwell curves (see above), and make the ignition sequential.

What I neglected to show here is the RPM vs dwell % screen.
This should be flat at 100%.

The AEM has a funny 2x factor in calculating dwell.

e.g. "coil factor" = 21 would make you think it means 2.1 ms. That would be correct.

However if the RPM and Batt volts factors multiplied produce 100%, the resulting dwell will be 4.2 ms. In order to get 2.1 ms, they should multiply to 50%.

So in my first post above, if RPM factor is at 100%, at 14.4V Batt factor is 50% ... the result will be 2.1 ms.