And I thought I was insane! Took it apart just to see? Moved to the next level mate, well done (for the results too)!!!
As you say, you’re almost sure ignition and fueling is equal to all cylinders.
The only thing that’s left then is beyond us I’m afraid (unless you have a bench dyno, 2-3 engines, 4 AFRs and EGTs blah blah): specific real time air/mixture flow at 4 separate cylinders and actually the in between difference. There is always some due to design of manifolds, heads etc and this is why on most ecus there is the option to alter values individually (or pairs of cylinders) so they come ‘closer’.
I face the same problem, I like to think it does not matter that much if it gives me joy long enough, however I would like to solve it just for the heck of it.
Yes the mapper has suggested that unequal flow/head/manifold design could mean that cylinder 3 isn’t as obvious when ign/injectors are checked. It’s very odd but we know for sure that pistons, liners and head all visually look excellent.
We are going to measure cam lobes and piston height to determine if cam has worn already or perhaps a slightly bent con rod. Really not sure when standard rod’s start to fail. 32 psi off boost probably doesn’t help. lol
Press compressor together into its locked position on valve head and spring retainer, if you have it adjusted too right length you can now get out the valve collets with a magnet, then carefully release the compressor tool then the valve is free
What I do recommend is that you tape up the collet grooves in the valve or something, there is special plastic caps for fitting valves stem seals on with, as the grooves can damage the stem seals when pulled through
It was strange - I would have thought it would have played up all the time, but I guess the more boost you run, the larger the cylinder pressure, the greater the electrical discharge? Doesn’t make sense to me as you would think the electrical demand would be the same regardless.
