Originally Posted by Ben
The likely suspects are
-Ignition triggers wired in incorrect sequence
-fuel outputs wired in incorrect sequence (though ignition is more likely for the scenario you described)
-trigger angle 360° off
No I don't remember such a call. I don't think we've spoken in around 4 years Henry.
Hello again Ben,
To your three possiblities
3) This is how we fixed it. It was running with wasted spark and a 30 degree trigger angle. With Sequential, would not run at 30. Couldn't change trigger angle with stock trigger wheel - went custom trigger wheel and set angle to 390 and it ran.
If the "wiring backwards" referred to ignition outputs to coils connection, they were made thusly:
Spark A to Cylinder 1
Spark B to Cylinder 3
Spark C to Cylinder 4
Spark D to Cylinder 2
This was checked several times by myself and others. Really don't think I miswired the ignition or fuel outputs because if they were miswired, would advancing trigger timing fix the problem? Don't think so.
It was a Cam Phasing Problem, NOT an ignition sequence problem. Engine was firing 360 degrees out of phase. This was fixed by A) going to wasted spark and then B) changing trigger wheel and advancing trigger angle 360 degrees.
From the MS Extra forum, other folks have had a similar problems. No one else fixed it without going to a 24 tooth trigger wheel and bumping trigger angle 360 degrees After the patch, no one went back to see what the root cause was. Did all of these others make an assembly error? Not likely as Again, it was Phasing that was out, not sequence.
Another possibility is that not all MX5's came down the pike the same. Changes were made to the stock ecu's during the production runs. How many folksgo to the trouble of going sequential without also enhancing trigger timing resolution? Some, sure, but it reduces the numbers that would evaluate all the permuations.
At this point, I don't care much except for the fact that I'm building another MS3X and didn't want to go through this again. of course now, I know a quick fix which we were going to insall anyway, the 24/1 trigger wheel.
Yes, it was 4 years ago. Some things are memorable.