For some odd reason I'm getting knock retard even though I'm spraying meth through a snow performance stage 3 kit. I'm running 93 octane with VP racing fuel M1 meth 100%. But for some odd reason I'm getting between 6 to 8 degrees of knock. I checked the knock sensor wires and the black wire did show signs of chaffing and a small area of the wire was exposed. It fixed the wire and added wireloom to protect it. I thought that was the culprit but it wasn't!!! Still getting knock... any help would be greatly appreciated. Thanks for looking

Quote from: ddlopes on August 31, 2017, 03:37:01 PM
For some odd reason I'm getting knock retard even though I'm spraying meth through a snow performance stage 3 kit. I'm running 93 octane with VP racing fuel M1 meth 100%. But for some odd reason I'm getting between 6 to 8 degrees of knock. I checked the knock sensor wires and the black wire did show signs of chaffing and a small area of the wire was exposed. It fixed the wire and added wireloom to protect it. I thought that was the culprit but it wasn't!!! Still getting knock... any help would be greatly appreciated. Thanks for looking

Do you know for sure the pump is operational?

Too much meth can cause wall wetting which can cause knock.

Post some logs, it will provide insight...


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Yes I check the pump and it's working fine. I'll post some logs when I get home. Thanks for the reply. I don't think I'm spraying too much (350ml nozzle)... but I'm starting to spray 3 psi

Here's my logs...

To followup on FoMoCo's post:  Has the KR been there the entire time you have been tuned for meth?  A pump issue or a kink in the line have been the most frequent culprits hardware wise.  Then there's nozzle size and placement to consider.

Check the pcm to see if it shows any misfire events.  Hopefully compression is good.

I've started getting more and more knock as we continue to tune. I'd say the last 3 tunes. My nozzle placement is in a throttle body plate.

If no other options develop, consider retuning to a nometh tune to see if the KR is still there.  How does the engine oil look/smell, looking for fuel in particular?

You are in a throttle plate?  I want to say all but the direct port guys are running pre-blade nozzles, so you are possibly in a bit of less common territory.

Do you have a check valve in there so that the vacuum behind the TB is not sucking meth from the line before you start spraying?
3psi seems a bit on the low side, most people recommend 6psi start point. 

Combination of the two could have your with more meth being injected than planned and causing an issue?

I do like SHodded's idea of returning to no meth tune and verifying if KR is present before you keep running meth tune.  You want the car 100% solid before you add meth.

Quote from: ddlopes on August 31, 2017, 03:53:34 PM
Yes I check the pump and it's working fine. I'll post some logs when I get home. Thanks for the reply. I don't think I'm spraying too much (350ml nozzle)... but I'm starting to spray 3 psi

Isn't spraying at 3 psi a way bit early!! Z

Not sure, the progressive kit has a ramp up volume control.. but 3 psi is WAY lower than I'd expect.

*If* the volume of meth ramps to fast or has to high a initial flow it could be setting or even small amounts of fluid on the caps increasing g the compression.

I'd back off the onset to 5+ Pounds and retest..

Here's a datalog spraying meth at 6psi... still have knock. Yes I do have a second solenoid to stop the vacuum from sucking in meth.

Interesting things to note.. after cutting the data before the high speed and after the high speed (attached to post) I can see up to +7kr .. BUT it only occurs after shifting. 

during the non-shift WoT your only hitting 18spark on average but it is stable.. it is low for meth in my humble opinion but it is behaving as it should.

what is your elevation ?

others will need to chime in but this looks like a tuning issue or a fuel quality / meth quality issue or issue with meth delivery issue with the nozzle..

Quote from: ddlopes on August 31, 2017, 09:22:45 PM
Here's a datalog spraying meth at 6psi... still have knock. Yes I do have a second solenoid to stop the vacuum from sucking in meth.

It's pulling a ton of fuel and still well rich of commanded AFR.

Elevation is 164ft

Quote from: TopherSho on August 31, 2017, 10:51:12 PM
Interesting things to note.. after cutting the data before the high speed and after the high speed (attached to post) I can see up to +7kr .. BUT it only occurs after shifting. 

during the non-shift WoT your only hitting 18spark on average but it is stable.. it is low for meth in my humble opinion but it is behaving as it should.

what is your elevation ?

others will need to chime in but this looks like a tuning issue or a fuel quality / meth quality issue or issue with meth delivery issue with the nozzle..