Burst Knock? Help!!

[qwkvert]

Trying to figure out this KR, any help is much appreciated.

Merry Christmas

[joecar]

Please post your tune file.

[LastCall]

Posting your tune file would help. It looks very rich at WOT and your IDC hits 114% at 6200 rpm. As far as the KR you are seeing, some of that looks like BR, but timing still looks high with 5 degrees of KR and 22 degrees of delivered timing at peak torque.

What are the engine specs and what is it in?

[qwkvert]

Sorry i didn't get back...holidays.. It was burst knock, and I've been working on the wot rich issue, working it down little by little. It's an extra cab z71, 6.0 (lq9), ported 243's, 275hr cam. I have the flex fuel injectors, but I'm thinking the scaling is wrong for them that i have. I'm going to upload the current time in a bit if someone just gets bored and wants to school me on anything I've got f'd up. Thanks.

[qwkvert]

heres what I have so far

[joecar]

Is your FPR un-referenced...?

[LastCall]

Sorry i didn't get back...holidays.. It was burst knock, and I've been working on the wot rich issue, working it down little by little. It's an extra cab z71, 6.0 (lq9), ported 243's, 275hr cam. I have the flex fuel injectors, but I'm thinking the scaling is wrong for them that i have. I'm going to upload the current time in a bit if someone just gets bored and wants to school me on anything I've got f'd up. Thanks.

Sounds like a nice engine combo you have going. What year is the truck?

Regarding the tune, there has been extensive modifications made to it. If you are indeed running flex-fuel injectors, then your scaling is wrong. What is the part number for the injectors you have? Cleaning up the spark tables in the idle area will help in the transitions from park, drive, and while moving but idling. With that cam, 20 degrees should be enough. Copying the ECT tables from an 02 Camaro would be a good idea. Also removing the additional timing from the fuel mixture spark correction and cat light off tables, zero them out. I'd also richen up the PE modifier to 1.20, at least to start. You'll need to redo the MAF and VE tables if you change the injector settings.

It would be a good idea to get a wideband for the WOT portion of the tuning.

[joecar]

Which year/model/vehicle are the flex fuel injectors from (so I can go comparing in that tune file...)...?

[qwkvert]

the injector part numbers are 25326903. I had a suspicion that the injector tables I found were wrong, and have been tuning the thing to what I found. It really doesn't run bad, surprisingly. The truck is an 01, regulated on the rail. stock 78mm tb, stock exhaust(funds) without cats. Its a solid combo. Needs more stall than the I6 trailblazer converter gives me though. Thanks for looking this over. Now that Christmas is over, I'm going to get a wbO2 first, then worry about the exhaust and intake restrictions later, should make for a nice seat of the pants upgrade later down the road when I get bored with how it currently is.

[qwkvert]

after some research, and crossing part numbers, it appears these are the same as my wifes 03 suburban, which is flex fuel. I have all the data from it, so I will copy all those inj tables over and start over..............

[joecar]

Please can you post the 2003 Suburban tune file.

[qwkvert]

2003 Suburban flex fuel

[qwkvert]

huh, 3* kr from launching in 4x4 mode?? same launch in 2 had none? maybe becase it had a much higher load in 4x4 because it didn't just blow the 35" tires away like it does in 2wd? First wot was 2wd, 2nd was 4x4 after a couple minutes in the store. I pulled 2* out of it anyway to be safe.