Part Throttle Knock

[askoncemore]

Running Torque or SCT to monitor knock.

My normal part throttle knock never exceeded 2.

Now I am occasionally seeing part throttle of 6.

No knock at WOT.

LOR is really good and I have reflashed as well.

Any ideas on why I am getting this higher knock value?

 

[ajpturbo]

So sct knock sensor pid showed 6?...if your oar is really good then your spark tables are scaled to be aggressive...sounds lime it was an isolated incident...i wouldnt worry about it...if it continues then oar will rise and spark will be scaled back

 

[askoncemore]

Is it possible that a leak could be causing a lean condition at part throttle?

I am not sure it is isolated... it happens every day.

Is there anything I should monitor on my logs?

 

[ajpturbo]

Is it possible that a leak could be causing a lean condition at part throttle?

I am not sure it is isolated... it happens every day.

Is there anything I should monitor on my logs?

So much speculation on this forum...the normal operation is to ride the edge of incipient knock...so i would always expect to see some kr

Monitor knock sensor, stft, measured afr and spark

I doubt you were lean because 02 sensors will do whatever they need to for 1.0 lambda....you could also log lambse to make sure you arent commanding something leaner than 1.0 but i doubt it

 

[SHOdded]

Post some logs for AJ to analyze, he can tell you what all he would want to see (in addition to those parameters listed above).

Are you sure your WMI kit is working correctly?  If you use the meth often enough, the pump can wear out and need a rebuild.  Supply hoses can also become kinked, affecting the fuel system.

 

[askoncemore]

I will post my logs soon.

The part throttle is without the meth kit running.... no boost at part throttle.

 

[askoncemore]

Can someone look at my log to see why I am getting part throttle knock?

No knock at WOT.  It seems like it is at a certain load.

Thank you.

 

[SHOdded]

Looks like fuel control issues to me, whether it is the LPFP, FPCM, or the methanol, IDK.

 

[hawkeye93]

I have the same issue.  Generally light throttle, often when going up an incline.  Planning on changing my knock sensor, but I'm not confident it will solve the problem.

 

[ajpturbo]

The intention and factory knock logic is NOT to have 0 knock retard...its a dynamic knock logic.....i think philosophies of yesteryear are making people misinterpret the systems of today

 

[SHOdded]

The intention and factory knock logic is NOT to have 0 knock retard...its a dynamic knock logic.....i think philosophies of yesteryear are making people misinterpret the systems of today

So what is your insight into this, AJP?  Perfectly normal for Gray Brick's setup?

I have the same issue.  Generally light throttle, often when going up an incline.  Planning on changing my knock sensor, but I'm not confident it will solve the problem.

Any logs?  How much KR?

 

[hawkeye93]

No logs, but I've seen 7* on my x4.  Seems like a lot.  Even running the stock tune and premium gas, so I'm pretty sure it's not a fuel quality issue.  I'll try to get some logs to post.

 

[ajpturbo]

Cant type alot now but i look for trends...if its an isolated 7 i wouldnt worry but would pay attention...if its regular and you are using high test fuel you can narrow it down to hardware problems and false knock from noise OR spark tuning that is over advanced....your tuner would have to run tests to rule out the tuning

I dont like seeing more than 4 but seeing 1-3 during a pull doesnt bother me at all considering stock can show at least that

Thats why i also like logging a 3rd gear sweep and a multi gear pull from 1st -3rd because sometimes one pull will pull spark and one will add so i dont worry if i see that...if they both are always pulling then i adjust to see if its spark or noise

 

[hawkeye93]

Here's a log with stock tune and 92 octane Top Tier gas from Costco in the tank.  KR maxed out at 3.84, but I have seen higher.

 

[askoncemore]

I am contemplating on replacing the knock sensors as well. If I'm going to pull the manifold off to check the wiring I might as well replace them. The knock just seems to be getting worse and worse as the car ages. Thankfully I don't have any knock at wide open throttle. The meth kit doesn't come on till 8 PSI so part throttle knock is with very little boost and no meth.

 

[FoMoCoSHO]

This is posted elsewhere but I feel it's pertinent to the thread...

http://stratifiedauto.com/blog/understanding-knock-and-ignition-corrections-in-your-high-performance-ecoboost-engine/

 

[askoncemore]

Adding a gallon of methanol to my tank removes the part throttle knock.

The knock sensors must be working correctly.

 

[griggs95]

Adding a gallon of methanol to my tank removes the part throttle knock.

The knock sensors must be working correctly.

So you haven't done anything since this post was started? Knock sensors still stock? How many miles on the car since this issue?

 

[askoncemore]

Original knock sensors.  The car has been modified in many ways and still knocks on the stock tune.

Again... when I add a gallon of methanol to the tank the part throttle knock goes away.  I am thinking with all of the intake and exhaust mods the fuel might be a little lean on part throttle.
I have discussed it with AJP and he is aware.

 

[griggs95]

Thanks for the updates, my car did something similar last year but i believed it was bad fuel. Returned to stock then it did it again (stumbled). Redid knock sensors with new loom (fuel lines) instead of plastic wire loom and reset KAM and such; am still not certain as to what it was/is.

My car is not modified like yours so not as much to try and figure out. Simple tune and down pipes but its been fine for awhile now. Car is sitting currently though the winter so we'll see soon enough. E-10 fuel has a 3 month shelf life under ideal circumstances before it starts to break down, E-0 is years. I get E-0 so that is what is stored in it now.