Hi there,

anyone have any idea what the degrees BTDC is for my 4G15 engine ('91 lancer CB carbi)? I've been having bad pinging mid-throttle under any kind of load, general gutlessness and a very notable on-cam step up in power after about 2/3rds revs (no tacho sadly).

I checked the timing (couldn't isolate the ignition timing sensor screwed to the firewall though) and it came in at 9deg BTDC. I then changed this to 3-4 deg, which has cured the pinging, muted the on-cam effect and makes the engine feel a bit more powerful. BUT now my shift points have changed from 30/45/65kph for 2nd to 3rd/3>4/4>5th to around 40/55/70. Is this normal? My Haynes manual doesn't give a BTDC value and refers me to my car emissions control label which for the life of my I can't find.

I'm going to retard it a bit to 5-6 deg BTDC and see what happens. I guess my sweet spot should be just before it starts pinging again, any advice?

thanks in advance!
matt