I've learnt a difficult lesson over the last couple of months.

I'm driving a 2012 991s in Basalt Black and have always found detailing my cars a joy, both the process of washing and then enjoying the results.

I've honed my skills from years of trawling through detailing world an autopia and mastered a pretty good detailing process as well as accumulating a pretty gigantic haul of products and tools

Anyway, onto the 991. This isn't a black car nightmare thread, rather more stressful than that. I have had 3 instances of the "failure of the engine control system" warning that have meant inconvenience and a trip to the dealer. Each instance of this failure was preceded with a misfire than "corrected" itself but then left the warning message on.

For a while I never made any connection but each time this failure occurred I had previously washed the car. I think I am somehow getting water into the engine. After a bit of research it seems there are a few posts on this topic. My "fix" for this will be to cover the air intake and fans with a drying towel prior to pressure washing. I will also just direct the jet at 90 degrees to the slats rather than directly towards them.

Has anyone else experienced this issue? I can see that it is more common on older (more enjoyed) cars with cracked coils but this cannot be the issue on a 991 with 4k miles only.

Any experience or advice would be welcome.


m33

 

You power wash your 991?

 

I (stupidly) drove through 18" of flash flood water over the summer and can vouch for the improved water resistance of these cars and motors. Passed stalled sedans and took waves over the hood, but the 991 kept going without a sputter! I can also tell you when washing my old 996TT, any water through the rear lid vents would result in steam and squealing of the drive belt during startup as the entire motor would get soaked! Another area dramatically improved on the 991, although I wouldn't direct a power washer there!

 

The pressure washer is a key part of the snow foaming stage. The inference not to PW a 911 seems faintly ridiculous.

Reassuring point the on the 996TT as not directing the PW face-on would easily remedy my issue, or even just wind the pressure down when doing the rear deck

m33

 

Make sure you warm the engine up when you wash and store the car after the wash. If you start the cold engine a couple of times and then store the car overnight, you can get misfires when you restart it the next time

 

IMHO you have an electrical issue that needs to be tracked down before it starts to cause problems when dry. It's not normal for misfires to occur after washing regardless of how you do it.

 

Must admit this is my dominant thought. Its been with the dealer 3 times, the last of which was for 7 days whilst they tried to track it down. They didn't find anything conclusive unfortunately.

The washing theory may just be me grabbing at straws

m33

 

Easy test
Try had washing rather than power washing once and see it happens. If not then go back to power washing and see if it happens.

 

Pressure washing? Not on my paint.

 

Pressure washer is just for the foam gun. I don't believe he is hitting the car's surfaces with high psi water. The foam gun really 'foams' when you use a pressure washer.

Is this what you are doing OP?

 

Really surprised at the pressure washer reaction as its pretty much standard practice as described on Autopia/DW and is widely used by all professional detailers.

Moe Mistry recommends use of a PW in this thread:-

https://rennlist.com/forums/concours...-question.html

A little care, ie fan spray, decent distance from the surface and you get a totally effective way of removing dirt before making any contact with the paint surface as part of the follow-on 2 bucket method. IMO much more likely to reduce the chance of swirling compared with a lower pressure hose that will not remove so much muck before you start wiping the paint surface with your mitt

What's the hang up?

m33

 

^+1, I use a pressure washer with foam gun , then pressure wash rinse (really great in wheel wells), from about 2'. Before any hand washing.

 

i've been watching this thread for a bit and i think the whole anti-PW sentiment is pretty ignorant. obviously if you keep the nozzle an inch from the body and blast into seams, you are going to damage the car's finish (and potentially the car itself). if you know how to use your tools, you'll be fine

 

I would agree with this statement, I use a PW on flat black with no issues because I use it with caution.

Sorry OP, have not had that issue. Not sure its the washing...

 

LOL at all the anti PW folks. Most if not all pros use them. It's not like your using the paint removing stream head on your car. Pressure washing does far less damage than the initial swipe you'll make on dirt covered paint.