Thread: KR is winning!!!

Originally Posted by Smokin2000gtp

Actually the EGR is only activated during cruising situations and is never used at WOT, so the EGR wouldn't have any effect on knock. Now if the EGR was stuck open, that'd be a whole different story.

Question I have is....Without taking the EGR Valve off and inspecting it, how can you tell if it is working properly?

Originally Posted by Smokin2000gtp

Actually the EGR is only activated during cruising situations and is never used at WOT, so the EGR wouldn't have any effect on knock. Now if the EGR was stuck open, that'd be a whole different story.

If you bothered to read my issues, I do have knock at cruise. Only when the engine is reaching its operating temps, and only when cruising under load (up a hill or something). I've found dozens of sources that point straight to the EGR valve not supplying any exhaust gas when expected. The PCM advances timing which is okay (assuming exhaust gas was indeed recirculated, since the combustion chamber temps drop due to the inert gas thinning the mix), but if there's not EGR function due to clogged tubes or a malfunctioning EGR, the combustion chamber temps are rising and the advanced spark definitely doesn't help resulting in knock like I'm seeing.

Hope I explained it well enough.

I disabled it using the method TDCRacing suggested. Initial results are promising. PTKR has dropped substantially. Either the EGR is faulty or dirty or the PCM just expects too much of it. My PTKR is near zero now, with occasional blips (which I'm told is unavoidable). I'll post before and after scans later.

Next, I'll be seeing if I can get into PE mode without the KR suddenly spiking.

More update. PE is still causing problems...

As far as the EGR deal, it works... kinda. The flash KR is gone so you don't have to be touchy with the throttle to avoid the PT KR. But, if you hold it for more than a few seconds (say 20-25% TPS with the TCC locked) then it starts to come back as the combustion chamber temps rise with the sustained load. That's what the EGR is designed to fight.

I think mine is clogged. Tomorrow I'm going to hunt down a EGR gasket, a pipe cleaner, and some TB cleaner (cleaning the TB too) and give it a go. Carb cleaner will be used to clean the EGR pipes, but I'm taking off the TB so I want some TB cleaner too.

I still don't understand why as soon as I hit PE the KR jumps by 3-4* from what it was just below PE (as I roll into the throttle). Anyone ever seen this before?

And my WOT KR is still present but goes away the richer the car gets. I wasn't logging (was playing with my friend on the way back from Buffalo Wild Wings) and noticed as the car was about to shift out of 2nd at WOT the KR had finally fully recovered and wasn't coming back and after the shift still wasn't there. I'm sure the RPM_vs_Time table had lowered the AFR to a point that it was enough.

Gotta do some more scanning as I straighten things out.

I was having similar issues with cruise knock up to 10* when uner light load and in overdrive. Disabled EGR and it dropped to around 3-4* scanned and compared with EGR vs no EGR saw around 5* increase in timing with EGR enabled. With EGR off my mpgs got worse by about 3mpg . I looked at EGR under hood and all looks fine, car has 26K miles. I reduced timing in the cruise/knock area at 1600 - 1800 rpm by 4* and knock is gone. MPGs are back up. I'm just wondering since opening up the exhaust and having less back pressure if it affects the amount of exhaust getting through the EGR valve and into the cyclinders, so the PCM thinks it needs more timing advance than it really needs. Just guessing but it's the only theory I can come up with.

Originally Posted by TDCRacing

So you reduced the main spark tables timing? low and high octane? Were they modified to begin with? Anybody can reduce the timing or add fuel usually to make kr go away but in my opinion there is a better way of doing things. In this case it would be to find the cause of all this. I Would never reduce the timing tables to anything less than what they were stock.


And I have never heard of MPG going up with reduced timing.

With EGR off timing was reduced everywhere and mpg suffered. There is nothing stock regarding the PCM. HPtuners does not support 2006 GP. Yes reduced main high/low timing tables. I looked at the difference with egr on/off and compared timing difference as I stated in my original post. This is cruise knock not WOT knock.

Originally Posted by Stonewall

I'm just wondering since opening up the exhaust and having less back pressure if it affects the amount of exhaust getting through the EGR valve and into the cyclinders, so the PCM thinks it needs more timing advance than it really needs. Just guessing but it's the only theory I can come up with.

To be honest, that does make some sense. There is some vacuum in the intake that sucks the exhaust through, but I wonder how much back pressure really plays in to it.