tuned car and still getting knock

[jd1828af]

i spent a few hours tuning my car by o2 volts and i am still getting knock. at wot the o2 is between .87-.93 which is right about where it should be. timing at wot is usually 18-21. now i dont get any knock over 1-2 except for one special case. ive noticed that if im going about 70-75mph in 5th and i drop to 3rd and bring it up to around 6500rpm i will cause knock from 4-14. fuel trims are: low-117% (caused by false knock) mid-99% high-102%

 

[LandoAWD]

I really don't see a problem. If you are getting 21deg up top...you should be fine.

 

[jd1828af]

last night i was going at about 75 for about a half hour and then i went wot and heard the knock alarm on the logger go off i look and my o2 was at .85 and timing at 25deg. thats in 5th at about 4k rpm. can anyone explain that?

 

[bjgarvin]

correct me if i'm wrong, but the ecu will lean out the mixture at highway speeds (not WOT) to increase fuel economy.

you might just be cutting it too close at that rpm in 5th gear.

Ben

 

[NOSLO2PT0]

4k rpms? that's false knock sounds like. Only time you should even look at knock/timing/O2's is at WOT at 5500+ rpms. But then again, NO part of a run at the track for me is under 5500rpm. Keep an eye on your #'s at the top of 3rd and thru 4th gear. That's the important area.

 

[kpt4321]

DO NOT tune by O2's, tune by knock.

Knock will not effect th fuel trims.

Knock counts of 1 or 2 are not a problem, as long as it's not doing that all the time.

....Kyle T.