Issues with tuning my 6.2

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RAPID

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Feb 18, 2019
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Hey Everyone!
I recently did a few small upagrades to my 07 6.2 Denali. Just a CAI, Gibson shorty headers, high flow cats and free flow muffler. Shortly after I ordered the Diablosport Intune I3 tuner and uploaded the canned tune. With 93 octane fuel I immediatly noticed engine detonation at high RPM under full throttle. I tried a different tank of fuel and it still did it. I had a local shop hook up their scan tool and they said it was clearly engine knock. So I messaged my tuner (Diablew) and had him look at my data log and he said I either had air leaks or a fuel problem. I spent hours verifying the AFM was clean, replaced all intake hoses, installed 4 new oxygen sensors, new plugs and wires, replaced my intake manifold gaskets, cleaned the TB and inside the air intake while it was off, verified there we no leaks in the intake/exhaust with a smoke test and watching live data, and ran 3 bottles of Lucas fuel injection cleaner through the engine. I still have spark knock and nothing has changed. If I run the stock tune there is ZERO spark knock but once the canned tune is installed it detonates. Any ideas? The tuner said it could be a bad injector or fuel pump issue but data logging over an hour of driving indicates there are no issues and the engine runs flawless otherwise...
Any input would be much appreciated!
 

swathdiver

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Hey Everyone!
I recently did a few small upagrades to my 07 6.2 Denali. Just a CAI, Gibson shorty headers, high flow cats and free flow muffler. Shortly after I ordered the Diablosport Intune I3 tuner and uploaded the canned tune. With 93 octane fuel I immediatly noticed engine detonation at high RPM under full throttle. I tried a different tank of fuel and it still did it. I had a local shop hook up their scan tool and they said it was clearly engine knock. So I messaged my tuner (Diablew) and had him look at my data log and he said I either had air leaks or a fuel problem. I spent hours verifying the AFM was clean, replaced all intake hoses, installed 4 new oxygen sensors, new plugs and wires, replaced my intake manifold gaskets, cleaned the TB and inside the air intake while it was off, verified there we no leaks in the intake/exhaust with a smoke test and watching live data, and ran 3 bottles of Lucas fuel injection cleaner through the engine. I still have spark knock and nothing has changed. If I run the stock tune there is ZERO spark knock but once the canned tune is installed it detonates. Any ideas? The tuner said it could be a bad injector or fuel pump issue but data logging over an hour of driving indicates there are no issues and the engine runs flawless otherwise...
Any input would be much appreciated!
Can you see fuel pressure in your 2007 Denali? We cannot see it on a scan tool in 5.3 Tahoes and such for 2007s. What are your long term fuel trims (LTFTs) at idle and while cruising through town? A leaky injector should be able to be tested with a Tech-2 and of course, examining the plugs. Have you pulled them for inspection?

Having said that, I suspect that the "canned" tune is not for your truck. Lew can do a custom tune or you can get Justin at BlackBear to do it remotely.

If you cannot see your fuel pressure in a scan tool, you're going to need a gauge and a length of hose to stick it under your wiper so you can see it while driving.

It ought to be 43 psi when idling or running at WOT and not lose more than 5 psi after the key is turned off after two minutes. Key on, the rail should energize to almost 60 psi.
 

jwth

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Jan 3, 2014
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Michigan
Hey Everyone!
I recently did a few small upagrades to my 07 6.2 Denali. Just a CAI, Gibson shorty headers, high flow cats and free flow muffler. Shortly after I ordered the Diablosport Intune I3 tuner and uploaded the canned tune. With 93 octane fuel I immediatly noticed engine detonation at high RPM under full throttle. I tried a different tank of fuel and it still did it. I had a local shop hook up their scan tool and they said it was clearly engine knock. So I messaged my tuner (Diablew) and had him look at my data log and he said I either had air leaks or a fuel problem. I spent hours verifying the AFM was clean, replaced all intake hoses, installed 4 new oxygen sensors, new plugs and wires, replaced my intake manifold gaskets, cleaned the TB and inside the air intake while it was off, verified there we no leaks in the intake/exhaust with a smoke test and watching live data, and ran 3 bottles of Lucas fuel injection cleaner through the engine. I still have spark knock and nothing has changed. If I run the stock tune there is ZERO spark knock but once the canned tune is installed it detonates. Any ideas? The tuner said it could be a bad injector or fuel pump issue but data logging over an hour of driving indicates there are no issues and the engine runs flawless otherwise...
Any input would be much appreciated!
timing is too high or spark retard is not set high enough.
tune depends on blend of fuel at your local.
most tuners start with copying the high octane timing into the low octane table and then adding to them both, causes spark knock.
talk to BB.
each vehicle needs to be tuned to it's own responses, few canned tunes are really on the nut maybe close but just close.
 

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