Auto motive coil on plug

[noam]

We are trying to run our motec m4 with a HONDA Civic 2002 coil on plug (3 pins), 4 coils for 4 plugs.
With the ignition diagnostic mode – firing test, they fire perfectly (so it seems)
I am about to try and start the engine for the first time. The Crip is set (checked with a timing light) I am not sure how to determine dwell time.
Any one else using automotive coils on plug and can share his experience? Any tips? What am I missing?

p.s
I am trying the e mail MoTec support but havent heard back yet.

Noam

[noam]

We are trying to run our motec m4 with a HONDA Civic 2002 coil on plug (3 pins), 4 coils for 4 plugs.
With the ignition diagnostic mode – firing test, they fire perfectly (so it seems)
I am about to try and start the engine for the first time. The Crip is set (checked with a timing light) I am not sure how to determine dwell time.
Any one else using automotive coils on plug and can share his experience? Any tips? What am I missing?

p.s
I am trying the e mail MoTec support but havent heard back yet.

Noam

[Fulcrum]

How did you check the CRiP Value with a timing light without starting the engine ?
Regarding, Dwell time of the coils (Your coils are inductive, I am assuming that) you will need a current clamp hooked to a oscilloscope and a variable voltage supply . From the test utility vary the dwell time of the coil (Start with 1.0ms to be safe). You will have to find the knee point on the Current (v/s time) waveform . The Dwell time will be the time from the Start of the Waveform to the Knee Point on the waveform which looks like this.

http://www.flickr.com/photos/4...9167/in/photostream/ (http://www.flickr.com/photos/48312245@N00/5758929167/in/photostream/)

You will need to check the dwell time at various voltages 8,10,12,14V .
MoTeC Guys are very helpful, they will surely help you. They can even do the calibrations for you .

[noam]

For the crip value I cranked the engine without plugs so it can reach steady RPM with the starter motor (and a healthy battery). I hooked coil #1 to the plug outside of the engine and grounded the plug. I hooked the timing light to the coil and got a reading for firing cyl #1.
I am not sure I can test the coil like that, keep in mind it’s an automotive coil on plug with the module built in it so I can't actually hookup the coil itself, or I haven’t understand what you explained?

[Nicky]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Fulcrum:
How did you check the CRiP Value with a timing light without starting the engine ? </div></BLOCKQUOTE>

You do not need to start the engine to find the crip angle. The number degrees you rotate the crank from the Cyl1 being in intake to the cam trigger lining up with the sensor is the crip. You could get an accuracy of upto 0.5deg if done right. The rest you take care of by adding or decreasing on the ign table(be very careful while adding advance) while hooking the engine upto a dyno.

The general thumb rule is that if you have 4 separate coils with separate drivers(as in your case), start of with:
10V 12V 14.8V
2.4ms 2ms 1.8ms

If your battery falls below 10V while cranking, consider replacing it. These coils are built very robust and will still deliver a strong spark with higher dwells, but with reduced life and increased operating temperatures.

As Fulcrum said, you need to hit the knee point optimally, but incase you don't want to go that specific, I suggest the above table. It works well. You can add more axis points later to accommodate different battery types(Lion, lead acid etc). Make sure you have the right gaping.

Also, we tweak the table slightly when we change from the plugs we use for first starting the engine to the iridium ones. We do this to avoid fouling the iridium plugs with erratic fuel mixtures at cold start-up.

Hope this was helpful.