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Old 05-15-2008, 05:06 PM   #1
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Default EMU solution to COP/Dwell issue?

I am getting ready to do my COP conversion. I have the 1.6 ECU and EMU. According to some folks the dwell on the stock 1.6 ECU is somewhere around 5 ms. The Toyota COPS like 2.6. Rather than building the dwell reduction circuit, how would it be to convert to Direct Ignition rather than wasted spark?

The dwell would still be the same, but since the coils are only charging half as often the heat should be reduced. So not only would we save the coils, we could extend plug life.

Anyone have thoughts or opinions they would care to share on this idea?
Anyone converted to Direct Ignition? or sequential injection? ( how's that for hijacking my own thread?)

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Old 05-15-2008, 11:50 PM   #2
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Can the EMU do that with without an absolute #1 TDC reference? Even if you were to connect the CMP signal, that's one pulse per crank rev. Though perhaps EMU is smart enough to interpret the fact that the two CMP pulses are of unequal length. I can't find any documentation on that aspect of the unit.

It would be an interesting experiment. Step 1 would probably be getting the CAS connected. I never had mine hooked up, and apparently some folks early on had trouble doing so.
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Old 05-16-2008, 02:20 PM   #3
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The other problem is that the EMU won't run the COPs, period.
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Old 05-17-2008, 12:09 AM   #4
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It's interesting that you say that.

My own experience backs it up, actually. Last year when I had the EMU I tried to do a COP conversion. Nothing but fail. I never could figure out the reason they didn't work. Last week, I decided to try again. This time, with the MS, they worked like a charm.

But why? Is it possible that the trigger drive current requirement is so much higher on the COPs? The voltage requirement is certainly no different- both systems were running 5v trigger.

Seriously, any thoughts?
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Old 05-17-2008, 06:47 PM   #5
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I hate it when you guys are right.

I wired things up, but didn't close the loom. It appears they won't fire. I am going to test it on a stock 1.6 next weekend to validate my wiring. I guess they go in a box if they work and hope someone figures it out.

Thanks for the input.
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Old 05-17-2008, 07:00 PM   #6
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Chris, if you could make a few observations on the system, we might be able to find a solution.

My suspicion is that either the EMU does not have enough chutzpah on its outputs to drive the COPs trigger inputs or that the EMU does not like the fact that with the COPs in place, the tach line (black/white) is inverted relative to its polarity with the stock igniter.

Can you do a realtime current / voltage trace on the trigger lines? (You'll need an oscilloscope)
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Old 05-17-2008, 07:46 PM   #7
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Quote:
Originally Posted by Joe Perez View Post
Chris, if you could make a few observations on the system, we might be able to find a solution.

My suspicion is that either the EMU does not have enough chutzpah on its outputs to drive the COPs trigger inputs or that the EMU does not like the fact that with the COPs in place, the tach line (black/white) is inverted relative to its polarity with the stock igniter.

Can you do a realtime current / voltage trace on the trigger lines? (You'll need an oscilloscope)
Other than you and my brother in law in Michigan (EE) I am not sure I even know someone who can operate an oscilloscope, let alone has one, but I will ask around.
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Old 05-18-2008, 07:09 AM   #8
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i did get them to run on a 01. maybe the older ecu are having problems. the only problem i am having is durring cold start. when i crank the car it fires when i let the key go, not when it is cranking. but when the car warms up it works like stock. not sure what causes this. i am currently in europe and will test it when i come back and report but it woud be nice if we can make a circuit board to add to the harness or something. i am not electronically gifted.
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Old 05-18-2008, 10:30 AM   #9
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Quote:
Originally Posted by Chris Swearingen View Post
Other than you and my brother in law in Michigan (EE) I am not sure I even know someone who can operate an oscilloscope, let alone has one, but I will ask around.
Basically, I'd want to see channel 1 connected to either then brown or brown/yellow wire at the igniter harness and channel 2 likewise connected to the black / white wire. Can be on the COP side.

Channel 1 vertical at 1 volt/division, horizontal at ~1 ms/div, trigger on channel 1 rising edge at about 0.5 volt. Probe ground attached to a convenient engine ground.

Channel 2 vertical at ~5 volts/div. Ditto ground.

I need to see what that signal looks like during cranking with the COPs installed.
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