Losing Oil Big Time with no leaks

[vince_w2004]

For some reason i am unable to keep oil in the engine. There are no leaks that i can find and defiantly no oil spots under the car. The engine was rebuilt about 9000 miles ago and does not smoke at all. There is no oil in the intercooler piping, no shaft play in the turbo, and no oil on the plugs. And when i mean losing oil i mean about 2 quarts every week. My main question is if there is no sign of oil leaking when im driving (from the turbo) and it dosent seem to be burning any...where the hell is 2 quarts of full synthetic going???

 

[jamisonj24]

Well if it is'nt leaking visibly I would do a compression test and depending on those results a leakdown test. Your not showing any smoke out the exhaust or oil in coolant?

 

[vince_w2004]

No smoke out the exhaust but then again im in the car not behind it, defiantly no oil in coolant. If there is an oil ring problem wouldn't the plugs have oil on them? Gonna go ahead with the compression check this week but im assuming good compression because the engine runs strong.
I recently had it tuned at 10 psi (stock boost) and was dyno at 210hp at the wheels. Another thing is they said that it had been running really rich under 5000 and lean above 5000. If it has been running lean since the rebuild and the guy ran the car hard, what has that done to the engine in the last 8000 miles???

 

[bling5tatus]

Running the car hard while it's lean will cause fuel cut (correct me if I'm wrong).. and, if done over a long period of time, most likely compression problems through various means.

 

[jamisonj24]

Too lean Won't cause fuel cut. To lean can cause detonation, which can case damage to your pistons or rings or score a cylinder wall due to the higher egt's. A compression test will tell you if there is any problems with your cylinder/pistons or head gasket. Running way too rich can also damage the cylinder walls but takes a long time to cause damage.

 

[bling5tatus]

won't running lean cause lots of knock? And then the knock circuit will trigger fuel cut?

 

[vince_w2004]

Yeah i know a little about knock/detonation and figured it might have something to do with this problem if it is indeed bad rings already. Hope not but the only way to find out is to do a compression check so ill start there and maybe ill get some answers. Thanx to all and ill keep up the thread with the compression results.

 

[jamisonj24]

Nope. Knock does not trigger fuel cut, but running too lean will cause knock, running too rich can also cause knock. The ecu monitors air intake, if it thinks there is too much air comeing into the engine for the maximum amount of fuel it can deliver it will cause fuel cut to try and save the engine from what it sees as a dangerous condition for the engine. That is why when you lean it out you are tricking the ecu into see less airflow, thus delaying fuel cut because the ecu does'nt see the true airflow.