False knock

K

Kegsandeggs

New member
I've given up trying to diag this myself, and I'm looking for any public opinion or hopefully someone who has had this issue. I have the full cx racing intercooler kit, with the cruze intercooler (it's better), the cruze zzp intake, BNR downpipe, no resonator or muffler, but do have 2.25" straight pipe exhaust with the rs tip. Ddmw shift bushings, and rear brace, and eibach lowering springs. I listed everything because it could be coming from anywhere. While tuning with HPT it is getting a false knock at higher rpms... Anyone have any idea??? All of my ic piping is wrapped in foam where it meets chassi so it's not touching and my downpipe is wrapped also. I'm replacing the knock sensor as well as re torquing it today.
 
SONIC1.4

SONIC1.4

New member
Does the knock "grow" as the rpms and engine load increase, or is it a sharp spike to an immediately high value of KR followed instantly by the KR recovery rate?
 
SONIC1.4

SONIC1.4

New member
Make sure the knock sensor is not too loose or even too tight when you re torque it as I'm sure you know that could cause false knock :/
 
K

Kegsandeggs

New member
SONIC1.4 said:
Does the knock "grow" as the rpms and engine load increase, or is it a sharp spike to an immediately high value of KR followed instantly by the KR recovery rate?
Click to expand...

Increases as rpms go up, mid to top it gets worse...and I am going to re torque it, need to fine what spec is
 
SS1982

SS1982

New member
Knock Knock.....

I've noticed a knock my self on my 1.4l.. Not a tick like the injectors I know about that but at idle I can hear it inside the car and when I pop the hood. :( Sound like its coming from the passenger side of the engine. I bought it from a Cadillac dealer used and now have to find a Chevrolet dealer to deal with the Factory warranty. Just over 20k miles so this to me is unacceptable. Also having the 1st to 2nd grind at high RPMs.
 
M

MPFab

Supporting Vendor
How much boost, what AFR, how much ignition timing, what are the circumstances? Hard to give an opinion without pertinent info. If I can, I'll be glad to help. BTW, anything above 6,300 is going to be knock city. Most likely culprit is valve springs not keeping up with demand.
 
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Blue Moon Sonic

Blue Moon Sonic

New member
It's the octane you used. These cars run poorly on the 87 octane. I found that one out quickly when I started putting in premium non ethanol after the 500 mile break in period. Just ran smoother and didn't fall on its face until the 5k rpm mark from the tumblers in the intake manifold. Every turbocharged car or even sports cars needs to run premium regardless of what the owners manual says. Just because it can run a lower doesn't mean it is good for the car.
 
ChrisJ

ChrisJ

Active member
Blue Moon Sonic said:
It's the octane you used. These cars run poorly on the 87 octane. I found that one out quickly when I started putting in premium non ethanol after the 500 mile break in period. Just ran smoother and didn't fall on its face until the 5k rpm mark from the tumblers in the intake manifold. Every turbocharged car or even sports cars needs to run premium regardless of what the owners manual says. Just because it can run a lower doesn't mean it is good for the car.
Click to expand...

Oddly enough I ran 93 several times and gave up.
I've run 87 in my 1.4 for around 50,000 miles and for my purposes it's fine.

Sports cars may want premium. Good thing I own a Sonic. :popcorn:
 
ahtoxa

ahtoxa

New member
I actually used 93 for 45k miles and switched down to 87 about a month ago. I notice no difference. At all.
 
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