False knock culprits

[Bmaughan]

I was wondering if anyone would be up for helping come up with a list of false knock culprits?

I know it can be a million different things but I think some sort of list to get going on troubleshooting would be really helpful.

I’m currently experiencing very intermittent false knock and would love to get a head start on the process of tracking it down.

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[TX-Ripper]

How do you know it’s false?
Are you logging it?

 

[bluebeastsrt]

Assuming You’re logging. The most likely spot to start is headers and exhaust. False knock usually looks like a staircase pattern on your logs under hard acceleration. Maybe check intercooler piping next. Good luck.

 

[Bmaughan]

I have logged yes... it showed up while in the tuning process with Lund... and they said it was false... plus I’m running e85-e90 so it seemed that it was most likely false.

 

[TX-Ripper]

I have logged yes... it showed up while in the tuning process with Lund... and they said it was false... plus I’m running e85-e90 so it seemed that it was most likely false.

You can have them turn the sensors off/ desensitized

 

[markmurfie]

Anything metal that rattles. shake and bump test things while listening to the noise it makes. Higher pitch rattling is not good, hollow low thud rattles is ok.
rocks caught in the exhaust or other crevices like heat shielding is a big one, the exhaust near the frame touching lines or studs, the engine tilts you have to take that into account, noisy pulleys, AC clutch and compressor noise.
Internals like shattered ring lands, bad timing chain tensioners, VCT phasers, can also cause a rattle noise.
Torque converter and clutch noises from excessive slip.
Removing the rubber guibos from going to a one piece drive shaft can increase noise from the drivetrain picked up by knock sensors.
Double check all bolts and clamps are tight loose bolts allow things to rattle. Leaving bolts and nuts off that are hard to get to is unacceptable. secure your catch cans, the aluminium ones that free float right in front of the passenger head are always a concern.

increased routine maintenance of cleaning out the engine bay, under the car, and any where dirt and rocks build up. A jet of water is very good for this in certain spots, avoid high pressure water on or around electronics.
Change spark plugs and oil, and filters frequently. Go to gas station's with more than four pumps, the more the better, Pay attention to the previous dollar/ gallon amount spent and avoid ones that someone was using regular before you if possible. find the stations gallon counters figure out which one is premium keep track of it your self, find which stations have better turn over of there premium fuel. Your favorite station might not be the best station to get gas from.
With E85 test it.
Look at your fuels opacity whether its E85 or E10, cloudy usually isn't good as its an indication there's enough water in the stations tank to cause phase separation. This lowers octane of E85 significantly as its octane is usually from the ethanol and not the gasoline its blended with.
https://www.maine.gov/dep/air/mobile/documents/converting.pdf
Page 4 in this PDF, but its all good info on gas stations fuel and procedures.
File complaints to the station if you find cloudy fuel that makes your car run bad.

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