87 tune spark knock

[Murphy406]

Ok. I will post it tomorrow.

[Murphy406]

log the stock tune and see if it knocks

Well.... It looks like I have Max spark advance of 55 degrees, knock retard of 7.822 degrees, and total knock spark retard of 9.668 degrees with the 87 tune. With the stock tune I have 54.5 degrees spark advance, 6.504 degrees knock retard and 10.02 total knock spark retard. So apparently I just don't hear it on the stock tune. Any ideas what would cause this?

[Murphy406]

Is it possible to see which cylinders this is occurring on? I believe with my old predator I could log misfires and such. That is how I found a head gasket leak on my older 1999 Sierra.

[06MonteSS]

yes you can add parameters to log for misfire by cylinder numbers

[Murphy406]

Ok then I have another question. Is it possible the spark knock is being caused by deposits from the AFM from the last few years?

[gregory]

I wouldn't think so, mine is a 2008 with afm also and had 90000 on it before the tune was installed. Only difference is I got an 87 and 93 custom tune from Lew aka (monte66). I have had the throttle body cleaned and occasionally run royal purple fuel treatment cause todays fuels are absolute garbage with the addition of ethanol (water collection crap additive). luckily the afm did not cause an oil consumption issue, but it was always a concern for me. another thought would be to do a plug check and if they haven't been changed in around 80000 you might look into that, and be sure to use the iridium plugs. check the gap on the old plugs and see if one is way out of whack from the others, tell tale sign. Good Luck

[gregory]

Sorry Lew the custom tuner was the fella 06montess that is helping out here.

[Murphy406]

Sorry Lew the custom tuner was the fella 06montess that is helping out here.

I know who Lew is. I dealt with him with my old Predator. He had a wealth of knowledge for me back then. I had to register new because I couldn't reset the password on my old profile. My old email address got hacked and AOL wouldn't help me get it under control. Thanks for the help though.

And also, unfortunately I do have a small oil consumption problem. I am at about 105000 miles and it burns a little over a quart between every oil change. I replaced the spark plugs before I installed the tune. A few had some oil deposits but I have seen worse. It is a very strong running engine. I bet I will feel like I have a tune once I figure out why my timing is being retarded 10 degrees. Then the 87 tune should make it even better. I am excited and impatient at the same time.

[Murphy406]

Well, I have checked everything I know to check and I can't find the culprit causing the spark knock. Anyone have any ideas?

[Murphy406]

One more thing I noticed. I took a long drive and the LTFT is around 7 to 9 on the highway at around 2000 rpm I believe. Is that normal? I know on my old predator I was suppose to keep it between 0 and -2. Thanks for any help. Also this is still the stock tune. Only change is I removed the AFM and firmed up the shifts.

[Murphy406]

Anyone???

[Murphy406]

Well, months have passed and I still can't figure this out. I know it isn't bad gas. I have a 1999 Sierra as well with the 5.3 running the 87 octane tune with zero issues. I can log and watch the knock retard and it stays at zero. My 2008 Silverado pings away. I have to adjust my LTFT to -9 to get it to zero. Still pings at -9. I have changed spark plugs and wires, checked my fuel pressure. Has a clean air filter. I am stumped.

[06MonteSS]

Make sure you select/install the 87 octane tune from the Tune Vehicle - Advanced Mode menu..

if you are installing from the easy mode menu, there's a bug in the easy mode - it actually installs the diablo tune (that's the 91/93 octane tune - so timing is set higher)

so make sure you are installing from the Advanced Mode menu..

[Murphy406]

I will give that a try. I think I used advanced mode because I wanted the AFM disabled as well.

[Murphy406]

Made sure I installed tune in advanced mode. Spark knocks like crazy. Had to change my LTFT to -8 to get to -1 after I drove 100 miles. Looks like it is back to around 4 or 5 on my LTFT again. I took the truck to get checked out a while ago and they said everything is fine. Is it safe to go more than -10? Also now I am triggering P02270 and P02272.

I miss my old 1971 Chevy at this point. A trusty vacuum gauge and a screw driver fixed most fuel issues.