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Engine rattle under hard acceleration

3574 Views 7 Replies 7 Participants Last post by  Geoff sanvido
2008 6.7, auto trans, DPF,Cat EGR deleted.XRT Pro tuner set on tow mode
4inch turbo back flopro exhaust
Under hard acceleration engine makes a rattling sound. Mechanic says its engine knock. Gave me a cetane booster additive which helped a little. Can I adjust valve timing with my tuner to alleviate this rattle? What setting would be recommended?

thanks for any advice!
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Sounds like maybe too much timing, can you back the timing off a little and see if the rattle diminishes?
Sounds like you are experiencing Injector rattle. You shouldn't be unless you are 80-100 Hp over stock. I used to have that with my BULLYDOG Tuner before I went to EFI LIVE. Maybe you should consider EFI LIVE. Just my $.02
You don't need cetane enhancers for knock. Add some two stroke oil and see if that helps. It slows down the burn rate so pressure does not build as fast intially. JMHO of course.
The best plan is back down on timing/power. The next thing that comes is head gasket replace. Be advised.
I have the same problem, Smarty Jr (Tow tune and above). Worse when cold, better with Cetane boost.
Thanks to all for the advice, I will back off on the power and see what happens!
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