I'm having some problems with my 09 Si and the problem is white smoke from the exhaust. It does NOT do this all of the time and when it does it is when I am accelerating up a hill. Check engine light is not on and it also loses power when it starts to smoke. It did it real bad one night, I out some fuel injector cleaner in it and it was perfect for another 4/5 days. Did it slightly one night while working but quit after a few seconds and did not give me anymore trouble till a few days later. The other day it was fine to school, then slightly on the way back from school. Then when I left for work that same day it was real bad again. I only put 93 in it and usually never let it get past a 1/3 tank to keep it from getting low. It has about 140k miles on it. If anyone can help me it would be greatly appreciated so thank you in advanced. Once again, check engine light isn't on, only 93 gas, rarely goes above 4.5k rpm, spark plugs are pretty new.

 

Could be many things. Headgasket, fuel pump. Even though you used fuel injectors cleaner, one could me acting up. You should send them out to get professionally clean and flow rated. This might not be the healthiest thing but next time it starts to smoke take a whiff of it. That could tell you what it might be.

 

needs compression test

 

White smoke in the exhaust usually means coolant is getting into the cylinders. The head gasket is the usual culprit, but has anyone thought about the intake manifold gasket? This is just as likely and not quite as expensive to replace.

 

Any update?

What about the fuel pump? Could it be going out since it only does it going up hill?

I have noticed with fuel pumps when they start to go out, when they get under a load they can't supply enough PSI.