Having had an IMS Failure on my '04 Boxster S in April of this year, I'm wondering if there have been any failures of any kind on the new engines.

I know the new engine does not even have an Intermediate Shaft, so that sounds like it might be a solution to the old problem.

I'm on a 2 year warranty on the new engine and I'm considering a move to a newer car with a DFI engine in the future, at least before the warranty ends.

 

DFI only been out now 1 maybe 2 years in Cayenne and of course just out in the other Porsche models.

BTW, at local Porsche dealer last week and spotted not one but 2 Cayennes in shop each on lift each with engine out. Engine's not torn down though so I think engines were out for some other reason. One Cayenne had its running gear out. I snapped pics of all this.

There has been some talk of the new engine suffering from excessive intake value deposit build up on the intake side of the valve. Since fuel injected in combustion chamber now and not in intake port just ahead of intake valves there is no fuel spray to wash desposits off of valve.

Do not know if this will turn in an Achilles heel of major proportions or just be a problem for a few owners.

Had I not found a Turbo I was seriously thinking of buying a new 2009/2010 Porsche Cayman S with a new DFI engine but not with new PDK but with a 6-speed instead.

You've got some time before you need move to a newer car. Sit back and watch and see what turns up regarding these new engines.

Sincerely,

Macster.

 

Apparently the intake valve deposits are occurring in several car brands with DFI (not just Porsche).

 

Interesting. The 4.6L V8 in the 1996-1998 Ford Mustang Cobra had similar issues. Although a 32 valve engine, airflow to the secondary intake valves was closed off below 3250 rpm to promote low end torque. The fuel injectors would only spray fuel into runners of the primary intake valves, and as such the secondary intake valves accumulated quite a bit of deposits.

Best Regards,

 

928 models suffered fron intake port carbon deposits 20 years ago...... At that time the "cure" was to remove the intake manifold and walnut shell blast the ports, clean the injectors and check it ran ok afterwards.

I have seen carbon deposits keeping valves open on one 996 engine this year.

Part of it comes down to slow driving (heavy traffic) stop-start driving (heavy traffic), very short trips and commuting and extended oil changes = engine problems.

 

But with DFI the intake valves DO NOT get a spray of gas on them which tends to do some cleaning. So carbon might build up more quickly in the DFI engines. That's the theory anyway.

 

Keep a watch on the Cayenne because they were the first to get DFI and the majority of Cayenne drivers put way more miles on them then a 911 or Boxster owner.

 

by the variable valve timing to dilute incoming air with exhaust gases to lower combustion chamber temperature and reduce Nox emissions.

Hot gases come in contact with relatively cool intake valve and stuff condenses out onto valve.

Also, crankcase fumes pulled out of crankcase and routed to intake to be burned contain still some oil and other stuff which can end up as deposits on valves.

Do not over fill engine with oil. And my advice would be to drain oil more frequently, especially if car not used much. As oil ages build up of water and unburned gas make oil thinner and more likely to foam and aerate. This results in more stuff in crankcase fumes routed to combustion chambers.

Sincerely,

Macster.