knock at part throttle

[LTQuick]

Today I got my data logger hooked up. I'm now getting knock when accelerationg a little out of cruising (always off boost). If I let off slightly and return it will knock again. If I let off slightly and go wot it will accelerate with knock all the way up. I don't belive I have a vacume leek but I will be building a tester and testing on next monday. I'm unsure of the cause unless it is running lean, but why only at part throttle. I currently have a walbro 255, rewire, aeromoitve fpr at 40lbs, stock injectors for fuel. 16g turbo at stock boost. Any help would be greatly appreciated.

 

[RavenX]

Make sure the knock sensor is torqued properly first and then do a boost leak test.

 

[1990EclipseGSX]

Good possibility it is phantom knock. Your car is not really knocking, the knock sensor is just picking up what it thinks is knock from noisy vavletrain, carbon caked on piston tops, etc. Mopar Combustion Chamber Cleaner and Seafoam can usually help quite a bit with this...
Here are some links on how to clean your engine with MMCD.
http://www.outreach.psu.edu/users/res122/DSM/
http://www.neons.org/howtos/MoparCleaner.shtml

Could you post a log of this happening?

 

[andymoraitis]

The above two suggestions are absolutely correct. I would peg it to a knock sensor issue, but also think a log would be helpful since O2 sensor failure can also run you into rich knock. Typically, a failing O2 will cause lean readings on the logger and the ECU will compensate by dumping enough fuel to trigger rich knock.

Perform a boost leak test, check the knock and O2 sensors and let us know what you find.

Andy

 

[LTQuick]

I'm going to replace the o2 sensor (over 100k miles on it), check knock sensor, and do a boost leak test this next week and I will post the results. Thanks for the help.

 

[dnhieu]

Make sure the knock sensor is torqued properly first and then do a boost leak test.

if the knock sensor isnt torqued properly will this cause a knock issue? right now i just have mine in hand tight. i know it only neededs to be torqued to something like 6-8 ftlb.

 

[LTQuick]

I instaled a new o2 sensor and now the knock only occurs around the 3000 mark to the 4500 so I belive it is a phantom knock. I didn't get around to a boost leak test since most of my times was spent either in the rain or installing an alarm (whitch was the priority of this visit). I will check torque of the sensor next time I'm up there. My manual has been loaned out, so where is the knock sensor located? Thanks again