What causes a Porsche 911 engine to wobble?
The wobble occurs at the bottom of the stroke and results in the piston skirt dragging against the cylinder wall thereby scoring the liner. More recently, this issue has also been seen on the later engines. An early telltale sign can often be one exhaust tailpipe being more sooty black than the other.
What causes smoke at the start of a Porsche 911?
The smoke at startup can also be caused by a air oil separator (AOS) that is going bad but not completely failed yet. The M96 and M97 engines are famed for cylinder scoring – deep gauges in the cylinder liner, usually associated with a knocking noise and eventually catastrophic engine failure.
What happens when the air separator fails on a Porsche 911?
When this unit fails, the result is oil sucked out of the engine and into the intake. While the air-oil separator will not cause immediate mechanical damage to your engine, it may make it smoke tremendously and/or run roughly (see Pelican Technical Article: Porsche 911 Air Oil Separator).
What causes an oil leak in a Porsche 911?
A failing air oil separator (aos) is the likely cause of rear main seal failure and oil leaks, as it is in other VAG cars. Crankcase vacuum exceeds the normal range in the engine under heavy acceleration and sucks in air damaging the rear main seal.
Are there any problems with the Porsche 996?
Not all of the 996 cars will have the IMS problem, and it can be rectified for a few grand if you’re concerned, but it’s on the mind of every buyer out there. IMS problems aside, the 996 is absolutely stuffed with fragile, fast-wearing and expensive components, many of which can’t be reached without dropping the engine.
Can a failed IAC cause engine stalling at idle?
A problem with the IAC should throw a P0505 code. A failed/problematic IAC can cause engine stalling when off-throttle, and/or excessively high engine rpm, particularly at idle. The IAC, signaled by the ECU, controls the throttle opening at idle.
Why did the Porsche 911 M96 engine fail?
The M96 engine that powers these cars is subject to complete and total failure due to a weak intermediate shaft (IMS) bearing, a valvetrain component that fails often and requires a total engine teardown to replace, leaving the owner with a 3,100-pound paperweight and a $15,000 bill.
What is the problem with the idle air control valve?
The problem may involve an annoying change (up/down) of engine speed while cruising at a steady pace, a low drop (or even cut-out) at idle or when approaching a stop, a wild high engine speed of several thousand rpm followed by a drop to near zero, etc. • Dirty/sticking IAC (idle air control valve) (P0505)