Thread: 5.0 SC supercharger knocking causing misfire in cyl 5/6 ?? HELP

Hi all,

One of my 2016 5.0 SC's had a full timing chain, tensioners, guides replaced for some preventative maintenance, once it was put back together, we started getting mis-fire on cyl 5 and 6, so the first 2 cylendars closest to the radiator on the passenger side.

Mechanic swapped spark plugs, coil packs from cyl 1 and 2 over to 5 and 6 - error code still shows misfire on 5 and 6. We unplugged injectors on 5/6 and it said circuit break, plus misfire, so we swapped 2 new injectors into cyl 5 and 6, still the same issue, even tried 2 old ones pre-rebuild and still the same issue - so its not blocked injectors.

We took the fan belts off after noticing the knocking noise so as to disable the supercharger, started and it ran like a dream. re-started a few times, no more misfiring.
We put the belts back on, supercharger, etc, started it and getting knocking noises then misfires.

Now, for reference we have replaced the SC coupler as well inside the snout. There is no more movement (by force of hand) in the SC pulley where as there was prior to coupler being replaced.

Could a faulty supercharger's knocking .. throw off the knock sensors under the SC screwed into the block, and cause the ECU to cancel firing cyl 5 and 6 ?

These engines have 4 knock sensors, 1 for each pair of cyl, i.e. cyl 1/2, 3/4, 5/6 and 7/8 each have their own knock sensor.

Thoughts ? it's driving us mad.. luckily i have another 5.0 SC which runs a treat ! this other ones becoming a bit of a project by the looks of it..

Sounds like a very odd problem and I can't help you past the troubleshooting you have already done, but have you tried the Jaguar knowledge base? This U.S. based Jaguar forum has a few people who are very knowledgeable with this engine in the XF and F-type.
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