Bad detonation with 87 octane tune

BiPo2005 · Post by **BiPo2005** » Wed May 21, 2008 4:08 pm

I have 05 2500HD 6.0 Gas and the U7193. I had the 87 octane tune in and had really bad detonation at WOT. I put the factory tune back in and no problem. I have since logged my LTFT's. Bank 1 is 4.96 and bank 2 is 3.57. This is done at 2100RPM in fourth gear at 65 mph. Should I go -3 on the slope and reinstall the tune?

Post by **06MonteSS** » Wed May 21, 2008 4:10 pm

go -5%

BiPo2005 · Post by **BiPo2005** » Wed May 21, 2008 4:49 pm

ok I'll give it a try and let you know. Thanks monte

CANUCKPREDATOR · Post by **CANUCKPREDATOR** » Wed May 21, 2008 5:08 pm

also watch your brand of fuel you use. Shell=bad, BP,Exxon=good

Post by **06MonteSS** » Wed May 21, 2008 6:17 pm

yeah, mobil, exxon, sunoco, amoco, and bp are the recommended brands...

Shell is for the neighbors car...

BiPo2005 · Post by **BiPo2005** » Wed May 21, 2008 9:07 pm

Shell is what I use, maybe I'll try BP now along with the LFTF's set right and the tune reinstalled. Thanks for the response, I'll let you know after some more testing.

Post by **06MonteSS** » Wed May 21, 2008 9:21 pm

a-HA!! yet another Shell user sniffed out!! hahahaha...

a LOT of people used to use Shell man.. and they ALL had knock / KR issues... I used to as well...

get rid of that and it will go away...

neonhomer · Post by **neonhomer** » Wed May 21, 2008 9:48 pm

Funny - I burn Shell in my truck and dont have any problems with it. Of course I also add a few ounces of Lucas fuel system treatment with all my fillups...

However, I avoid independent stations like the plague. No telling what gas they get. (A lot of them are delivered by Florida Rock and Tank lines.... )

I have good luck with Sams/Murphy USA, BP, Circle K, Racetrack and Sunoco. I prefer Racetrack or Sunoco if I can find it cheap enough.

BiPo2005 · Post by **BiPo2005** » Mon Jun 02, 2008 3:53 pm

Heres my update: I switched to Sunoco 87 and still the Bad detonation on the 87 octane tune. I set the slope at -5 like monte had said. It starts detonating at 3000 rpms. It runs great but I'm a bit confused on this matter. I only have 31K on it. I think I might try 89 octane to see if it goes away.

Grumpy_Aero_Guy · Post by **Grumpy_Aero_Guy** » Tue Jun 03, 2008 8:25 am

1) Make sure your engine is, otherwise, operating as designed. Have you tried to pull any trouble codes? If you have any engine related codes, I'd get them taken care of first.

2) If you run 89, and it all goes away, that explains a lot. If you run 89 Oct w 87 tune, and it still pings, then I would guess that something's wrong in the eingine, and it's running hotter than normal for some reason.

3) I assume you don't have any other mods on the engine?

4) Are you in a hot climate, or at altitude (i.e. Denver, e.g.) ?

Post by **06MonteSS** » Tue Jun 03, 2008 8:51 am

you may want to buy some CRC MAF Cleaner and take your intake apart and spray down / clean your MAF... have seen that totally cure a pinging/knocking issue for a couple of other guys...

BiPo2005 · Post by **BiPo2005** » Tue Jun 03, 2008 4:22 pm

First off it runs great. I have no codes when the factory tune is in but when I have the 87 octane tune in it will develop a evap failure code after a week or so. Go back to factory tune and its gone. Check engine light came on just today. Evap control leak detected (0455)
(2)Haven't tried 89 yet, waiting till near empty to get a full tank of 89. It doesn't run hot. With the Diablo on real time data it shows the ECT at 193-195 degrees.
(3) Only mods are Cold air kit with 4inch hose supplying cold air from where the driving light would be. IAC is roughly 55-65 degrees. Next is going to be exhaust.
(4)Not a hot climate. I'm in Northeast Ohio. Been 60's and 70's lately.

Post by **06MonteSS** » Tue Jun 03, 2008 6:13 pm

have you left the stock tune back in for over a week or two to see if you get the EVAP code??

BiPo2005 · Post by **BiPo2005** » Tue Jun 03, 2008 6:45 pm

Yes, I even took it back to the dealer and they couldn't find anything wrong with it. They said if it did it again just stop in, but I don't want to be stoppin in with a performance tune in place to mess up my warranty.

BC_Leadfoot · Post by **BC_Leadfoot** » Tue Jun 03, 2008 10:33 pm

I have a 2001 Sierra with a 4.8 and the u7198. I had pretty much the exact same problems. When I first got the tuner and ran the 93 with 93 fuel I believe I had no preignition problems, though I didn't really pay much attention to my kr. Then after a couple months I decided to switch to the 87 to save money on gas and took my truck on a 200 mi trip. My check engine light started comming on. I would check the code and it would be evap vent control failure. I also noticed that I was getting alot of kr while watching my data log. I started retarding the timing and going more negative on the injector slope to add more fuel and still would have kr. I used to use Shell gas and was told that was the problem. I started using only recomended fuels but still have kr and check engine. I also have started hearing a tapping sound comming from the lower part of my engine. It is quieter with the stock tune. I brought it in to the dealer to check out. After spending an hour they told me they really could not determine the sound without tearing down the engine and to just run it until it gets worse. So for now I have been sticking to the stock tune. I am going to try cleaning my MAF sensor like suggested in this string. I am eager to find an answer.

Bad detonation with 87 octane tune

Bad detonation with 87 octane tune

RE: Bad detonation with 87 octane tune

Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT

RE: Bad detonation with 87 octane tune at WOT