rcwilbur

I have some audible ping at low RPM's between 1200-1800 RPM and low load .16 - .36 g/cyl, but it is not showing up as knock retard. I have retarded the timing in those areas pretty significantly to around 20 degrees and it is better, but am still getting some audible ping (again nothing on knock sensors).

I doesn't seem to make sense to retard timing much more. Just wondering if others have experienced this. (LS1 Texas Speed 5.3 heads (10.95 to 1 compression), 93 Octane).

Ryne @ CMS

iTrader: (10)

whats your af there? is it still in closed loop ? what size cam?

rcwilbur

Yea. Still closed loop and controlling it pretty well to 14.63 (too bad I can't make it a little richer in those areas). Cam is a 224R with 114 LSA.

Hardrvin

iTrader: (1)

May sound counter intuitive, but have you tried going the opposite direction? Low load / low rpm generally likes a good amount of advance (30+). However too retarded usually resualts in a miss as opposed to knock.

rcwilbur

Thanks. I will take a look. I suppose I can first create a log to see whether there is a misfire in any of the cylinders.

I will try going the other direction. I started with the stock timing at low end and when I heard the pinging retarded timing. It does seem coutner intuitive to increase timing as a result of the ping. Thanks for your help.

outkast6991

iTrader: (34)

Didn't you alter the sensitivity from an earlier issue? If so I'd start there

rcwilbur

Yea. I did. But the PCM never pulled any KR at original timing and original knock settings, but I could hear the ping then too.

I could restore the original knock sensor settings, but I'm sure I will just get the KR at WOT and still have pinging in 5th and 6th gear without any KR.

Slowhawk

iTrader: (12)

Could be carbon build up on the pistons?

MM98

iTrader: (13)

Did you put any sealant on the rocker arm bolts after the head swap? Without it, oil will leak past the threads into the intake runners.

rcwilbur

Yea. I think it is probably carbon buildup. I used the LS1howto Guide to change the heads and cam. Great Guide and wouldn't have attempted it without those instructions. My piston tops looked a lot like the pictures in that guide and the thought of cleaning then crossed my mind, but then thought it must be just normal for an engine with 55k miles.

I've tried seafoam through the pcv inlet to the intake without much success. I did install a catch can and am surprised by the amount of oil it picks up.

I backed the timing off pretty significantly in the low rpm low load areas and the pinging is pretty much gone. I am new to working on engines. Just wondering if it going too in timing in those areas could be harmful. I don't feel any difference in performance.

rcwilbur

Yes. I put the red locktite on the threads. Thanks.