KR problems

[danthurs]

OK, this is driving me nuts. I'm on my 3rd engine now. To bring you up to speed. First engine started to show odd KR under light load, about 4* or so. I adjusted the tune but didn't help. Soon after I lost oil pressure and found metal in the oil. built a new L67, it lasted about 100 miles. Same odd KR sometimes as high at 14.9*, lost oil pressure and found metal in the oil. Lost a rod bearing. So I built a new L26 with a top swap. Was extra careful on build. Did a scan, and same odd KR. No metal in oil yet, that I know of. I have removed the supercharger belt, so no boost. I changed the timing table to a stock L26, still get KR. Don't want to kill another engine.

Here is what I have noticed. The KR seems to show up between 4% and 10% throttle position, and between 1400RPM and 1800RPM, with a little bit higher up from time to time. Adjusting timing down in those areas seem to have no effect.

As for the engine builds. All new sensors each time. Only parts transfered over was a S1x cam, a 8rib harmonic balancer, and the supercharger. Also a ported throttle body with a LS1 MAF. I think I'm going to swap out the TB and MAF and change the MAF table back to stock. Oh ya, injectors are the same. If anyone has any thoughts on this, please speak up. I've tried everything. Swapping out the HB is my next step.

Thanks guys.

[ssms5411]

You could always desentize the KR sensors with resistors. I did mine almost 10 years ago and still doing fine at 40% reduced.

[danthurs]

That wont correct the problem, something is making noise. I dropped my timing around 12* in some cells, I'm trying a few different timing tables.

[murphinator]

Only parts transfered over was a S1x cam, a 8rib harmonic balancer, and the supercharger. .

common denominators..... I would be putting a stock balancer on it and see if it goes away , thats the only thing I can see causing both KR and pounding your shot block to early death if its not balanced/broken or something along those lines

[danthurs]

Swapping out the HB is a step I plan to take if the tune changes don't correct the noise. It's a easy swap, perhaps a hour. Just need to find a stock one.

[danthurs]

Just to update on this. I swapped harmonic balancers, no change, I did a CASE learn, no change. That's a hard one to get as it wont let me start a CASE until I hit 165*, and I have a 160* thermostat. I also did a cylinder balance test and they were all withing a few percent, 98% to 102%

[gtp_cc]

If you pull timing and the knock does not drop that means there is external noise triggering the sensor. Check for worn mounts ect. Also swap on some stock coil packs. MSD coils and junk and are know to cause stupid problems.

[danthurs]

The MSD coils are long gone. I replaced the cam this week and the problem did not go away. I'm now looking at the transmission, mainly the torque converter. I unbolted the TC from the flex plate and it looked like the KR was gone. Perhaps a out of balance torque converter.

[n0dih]

I have the same issue, stupid high KR, no amount of tuning "cures" it, even on E85 still have KR that can get pretty high. 15 degrees is max anyway.

I am not convinced it is not real somehow. Not 100% either way....But to numb up sensors too much and find out that I am wrong is not the way I want to go....

Mine is pretty much stock, LS6 MAF was added after KR started, mine has seen this KR like this for the past 2+ years. Mine is 1400 to 3800 rpm, under load, but not WOT. WOT is pretty much KR free. But anytime you are crusing, say 55 mph and you give a 40% TPS stab of the gas, KR skyrockets.

I have tried 160 stat, no help, TR6 plugs, no help, TCC disabled, no help, stone stock tune, no help, EGR off, no help, replaced 2 of the 3 coils (rust), no help, put stock back on cleaned up, no help, tune the timing aggressively, no help, add a ton of fuel, no help, turn off MAF estimation mode, no help (this uses VE tables like an LS1), lock it in gears so no downshift, no help, disable TM and Shift Energy Management, no help. The only peculiar thing is to a point, it tracks PE mode, but I am thinking it doesn't do that as much as it used to. Before I could move PE to 100% throttle and I wouldn't get KR till 100% throttle.

Car isn't abused , just sees a lot of miles (160k now), You would think the last 60k or so this would have either destroyed the engine or it isn't real or the PCM just handles it enough to keep it alive.

Does yours do it not in gear? GM has a bulletin I think on KR at idle, worn converter stator splines or something like that. But that would be pretty noticed if you ask me. Mine has no KR at idle, only when cruising.

The MSD coils are long gone. I replaced the cam this week and the problem did not go away. I'm now looking at the transmission, mainly the torque converter. I unbolted the TC from the flex plate and it looked like the KR was gone. Perhaps a out of balance torque converter.

[danthurs]

I have no KR at idle, only when I give it a little gas. I started to notice it when cruise control was on and going about 45-50mph. Trans locked in 4th, start going up a hill, and KR would show up. Over time it got worse, a few degrees, then after a few months 15* I've built new engines, 3 so far, and even rebuilt number 3 with a brand new cam. Nothing left in the engine from the first. I had KR in gear, foot on brake, and a little gas. Had KR in park, and a little gas. After unbolting the torque converter I had very small KR at first, I think I was still in open loop and heat soaked. Then nothing. Just had another person on another forum I'm on say his 04 Grand Prix compG is having the same problem. Try doing what I did, unbolt the TC and see if the problem is gone. I have another TC coming, once here I'll be pulling my engine again and swapping it out. If the problem is gone I will be cutting the TC open and looking inside. I suspect a bad vain.

[n0dih]

I am wondering if the differential, which is very close to the rear KS is possibly the problem. Mine with 67k miles was perfect, and up to around 110k, but sometime after that the problem crept in.

Today I datalogged it and while cold, when KS is not monitored, it is very quiet, but as soon as it passes 70C, KR comes alive.

So I numbed up the KS from 1400 to 4400 rpm and power is back and the issue is still not heard. I would think if it was real, it would rattle like crazy, and nothing is heard.

[danthurs]

Had not thought about the diff. It was changed when I rebuilt the transmission.

What tables do I adjust to KS?

[danthurs]

Here's one of my scans.

[n0dih]

Knock Retard Attack Rate vs RPM. I took 25% of what the values were (in volts) from 1400 to 4600 rpm. Pretty numb in the main problem area. I will narrow it as I can.


Edit: Mine is set like this: 7.2088 7.2088 7.2088 7.2088 0.7912 0.8791 0.8791 0.8791 0.7912 0.7253 7.2088 8.0000 8.7912 8.7912 8.7912 8.7912 8.7912 8.7912 8.7912 8.7912 8.7912

Do not use if you have ANY risk of real knock and you have a keen ear that can hear the slightest sounds of knock!!!! Knock will break pistons and ring lands very quickly!!!! I am running 10:1 rich like this right now. I wouldn't go leaner, rich is safe....

Had not thought about the diff. It was changed when I rebuilt the transmission.

What tables do I adjust to KS?

[danthurs]

This is how mine is set.

0.0000 0.0000 3.1264 6.2527 9.3764 9.3764 9.3764 9.3764 9.3764 9.3764 15.6291 15.6291 15.6291 15.6291 15.6291 15.6291 15.6291

I'm going to try a stall test tomorrow if I have time. But reading the bulletin, it really sounds like I have a bad torque converter.

[n0dih]

Well had the family in the car and in traffic the coolant temps climbed and it knocked like crazy. Be very careful!

[danthurs]

Mine don't seem to be temp related, and I don't believe it's true knock. I've pulled so much timing from those areas and it had no effect. It has to be false knock as in noise. Been reading the GM service bulletin regarding false knock due to worn stator splines of damaged torque converter. So I'm going to do a stall test. Then pull the engine so I can get to the torque converter to remove it.

[n0dih]

Yup, I have seen pictures, but I think that issue would become very evident in short order too, and lunch the trans. I would think the stator splines would end up in the trans pan/filter.

Mine don't seem to be temp related, and I don't believe it's true knock. I've pulled so much timing from those areas and it had no effect. It has to be false knock as in noise. Been reading the GM service bulletin regarding false knock due to worn stator splines of damaged torque converter. So I'm going to do a stall test. Then pull the engine so I can get to the torque converter to remove it.

[danthurs]

Depends, I picked this TC up used. May have been damage before it went in my trans. My hope is swapping out the TC will eliminate the problem. If it does, I'm cutting the TC open to look inside.

[danthurs]

OK, an update. I replaced the torque converter with a stock one, and no change to the KR. I really have no clue what to try next. I've rebuilt and replaced everything. Any other thoughts?