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I haven’t cracked it either, and this one has mechanics scratching their heads. The vacuum seems to be influencing the intake in a way that doesn’t add up. What I’d really like to confirm is whether my absolute throttle position is normal or actually too low.
The car shows negative fuel trims when no air leak is present at idle, but on the move the trims sit around zero. If I introduce a small controlled leak, the trims return to normal. That makes me think the engine is effectively choking for air during deceleration.
I’d really appreciate it if someone could share their logged absolute throttle position at idle on a fully warm engine so I have a reference point.
Thanks
decel fuel cutoff…injector pulse goes to zero it freewheels
this is how it’s supposed to work. something isn’t sealing
Hello everyone. They say third time’s the charm. I finally gave in and tore the engine down for the third time — this time removing all eight pistons completely. After measuring the bores and pistons properly, it turned out that cylinder 8’s sleeve was distorted at the very bottom, which explains why the issue never showed up in earlier inspections. The piston in cylinder 8 also had incorrect clearance.
I’ve now replaced all eight sleeves and piston number 8. Hopefully this will finally resolve the problem. Quite surprising, considering everyone insisted that smoke on deceleration is always caused by valve stem seals or guides.
I’ll keep you posted on the results. Fingers crossed.
Can anyone advise on part number of the 4 bolts holding the supercharger top hat on. I cant seem to find it on the catalog.
