knock underboost

[markmullins]

someone help dont know what to do next. 98gsx,big16g, i put a get knock at idle during the day on my safc- any where from 5 -35 , then at night its fine... it was like this for some time, then recently when under boost i get a quick responsive back fire like if i was rev limiting, and a large knock like 95 . what should i look for, i checked all my plugs and my 4cylnder was beatup so i replaced and no revs faster but knocks easier, but under night time when its cool car runs great till boost starts to kick in knock happens under fast accel, or past about 8lbs.. i have it limited to 10 right now. any ideas? suggestions, ? im at a loss i put alot of money in my car and i cant even drive it underboost help please .

 

[burldude]

From what I have seen the safc knock count doesnt mean anything but jibberish . It is garbage , the knock counter does not work for 1g cars and I would assume the same for 2g. Number 4 cylinder beat up ? You are going to have to get more specific than that if you want any advice. Spend some time posting and give us all the information you can including details. Then we can get down to it

 

[markmullins]

ok ok, i hear i was at work sorry. ok my car shows knock on safc under idle during day at like 100f regular day here. at night its fine no knock. but as soon as i start building boost say around 8+ psi the car starts to hesitate, with a quick response from a backfire, the car jerks from loss in power i checked fourth cylinder the plug was burnt and bent with a real light amount of oil around it. i did a compression check all 4 are 175-180. i use to run 19 lbs of boost no problem i put a new block on after it had crank walk, cleaned the head new stainless steal valves, hks 1.2mm head gasket . problem just started recently did not notice because i had a mas problem. when replaced went to drive car hard . started knock nothing on my setup has changed . is it possible it revs smooth with timing being off by maybe 1 tooth, or it could have slipped ? im at a loss. boost is controlled with greddy pb-spec 2.

 

[burldude]

Check you cam timing ,as soon as you can without driving till you know that it is on Then start over with trouble shooting . Burnt and bent plug deffinetly doesnt sound good . Did the new plug get bent also ?