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Dave,
These are Denso smart coils requiring 5v logic signal from the ECU to fire them. No output coil driver necessary as with "dumb" coils.
You most certainly can measure resistance on a smart coil and I followed multiple procedures for these coils and of the several I tested, they were out of spec.
I had initially purchased the Audi pencil coils for the car but went with Denso as they were smaller and fit the engine better and have been used by many folks on 911s, including TurboKraft which sells them as part of a kit. As a Toyota product it also seemed logical to think that they were reliable, ubiquitous and economical. I couldn't return three of the the Audi coils (I did return the other three) so I tossed them into a box.
The dwell time I had for these coils was 3.5ms, but I saw that the cranking dwell was 6- I checked my notes and it should have been 4 and I can't recall why it was set to 6, so that may have contributed to fatigue on the coils...
The system is wasted-COP. I considered going full sequential with spark but the cost for an ECU that was capable (and had the other features I wanted) was more than double the cost of the ECU I went with and for a single spark low compression engine I felt the benefits to sequential spark weren't necessarily worth the cost.
Now, perhaps with COP sequential really is necessary as it reduces the frequency of firing and load on the coils. and if I find that to be the case (all research and documentation conducted thus far runs contrary to that) then I'll pull the eCU and wiring harnesses and switch to one that is capable of sequential spark...
New connectors are arriving today and I've already remade the harnesses- I have this weekend cleared to work on the car and hopefully solve this supremely inconvenient problem.
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-Julian
1977 911 S: Backdate, EFI/ITB, AC project in the works:
http://forums.pelicanparts.com/porsche-911-technical-forum/1106768-when-well-enough-cant-left-alone-backdate-efi-itb-ac-more.html
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