I installed a custom tune with my SCT x4 programmer from 5 star tuning and now have detonation issues. The detonation is not there until WOT. Is it a tuning issue or a mechanical issue? I've tried 87 and 93 octane. My truck can run off ethanol but in not sure if that's the problem. I have a warranty so it's not a big deal if something goes wrong and it needs to be fixed, it's just annoying to have. If I need to give y'all more info just let me know. Any help is appreciated. I am running 275/70/18 BFG kos and will be moving to 295/70/18 nittos. Is the extra weight causing load detonation? Uphill is really when it's bad which is why I'm thinking its load related

 

If it wasnt doing this before the tune but now doing after the tune I would say talk to the guy who did your tune

 

Could be the fuel quality or too much timing if it ran fine before the tune.. Try running a canned tune on your programmer and see if your still detonating..

 

I would reach out to 5 Star and let them diagnose and solve the issue.

 

It ran the same on canned tunes. I am back in Lubbock where the elevation is higher and the octane is lower than Dallas, Tx. I think my truck runs better up here and the gas seems better so I filled up this morning with 86 octane. 5 star has already sent me a new tune and told me to send them a DataLog if the problem persists. I put about 350 miles on the revised tune they sent me so the engine has had time to adjust. I had no problem passing at 90-100 mph but the detonation is annoying

 

if you blow a hole in a piston because of a timing advance from a custom tune i doubt your warranty will be good .. just saying.. put it back to stock and see if it still does it.

 

You think the gas "seems" better so you filled up with 86 octane?
If your running 86 octane which is a bit odd for a listed rating, then I'd say you need to run 91 or better and try a different gas station..
Usually it's e85 87, 89, 91, and 93 listed for sale.

You probably can't run e85 with the 5 star tune that's for 89 to 93 octane.

If you had a problem with detonation before than I suggest you get a tune up, it's also possible your misfiring and not detonating.

 

^ I agree, put it back to stock and see if you still have the detonation. If not, call 5 star again.

 

It's 86, 88 and 90 in Lubbock. I ran stock all last year on this gas without issues. I can post a picture if you think I'm wrong? I've been filling up in the panhandle for a while and I'm pretty sure I know it's 86.

 

I had misfiring before which was fixed and it didn't make the clatter noise