Hi everyone,
I am having a knock problem with my 2.5 g-head. I finished tunning my cal a few months ago and it runs great, I blew a exhaust manifold gasket so I pulled it all apart and replaced the gasket. Now everything is back together and I have been getting the CEL knock light flashing occassionially. Sometimes It will come on at 4 psi sometime at 10, and sometimes never. Other than replacing the gasket the only thing I changed was the oil which I switched over to full synthetic Valvoline. I did fill the tank up right after I put it together. I must have tightened the adjustable wastegate a little tighter when I put it together because I had about 2 psi more boost. My EGT's and wideband are all in range and my plugs look fine. I pulled 2 degrees of timing and added 2% more fuel to the cal and I took it for a ride, the light did not come on. Then it started flickering again. I cannot hear any knock. I am stumped as to what could have caused this problem. I thought it was bad gas so I fulled up with gas from another place and it is still there. I guess it is possible more than one place has bad gas. Could it have something to do with the synthetic oil? I have not taken notice of it using any oil. The engine has wiseco pistions. Any advice would be appreceiated.
Thanks,
Justin