Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

2004 Cayenne s 8 cylinder 5 of 8 plugs wet with gas

Recommended Posts

Checked compression this morning with car cold (65 degrees outside)


I had 120 across each cylinder ... compression seems low but I'm getting feedback Because it wasn't a warm engine but the same reading across all 8 is stable.. could my misfiring and unburned fuel be a valve issue at this point.

Link to comment
Share on other sites

    You can remove these ads by becoming a Contributing Member.

  • Moderators
12 minutes ago, Renzo511 said:

I do not have leak down test equipment. 

Is the fact that each cylinder compression is almost identical to each other a good thing ?


They are equal, but lower than I would expect.

Link to comment
Share on other sites

On 30/04/2017 at 6:03 AM, Renzo511 said:

Is 120 psi across all 8 cylinders  ( 1 or 2 psi variable ) on a cold engine bad ?

Don't seem right to me. I thought 180 was more like it. 

Other cayenne S owners recorded 180-200! 


You stated you had 170 before and number 8 was lower at 158! 


I'm confused now? 

Edited by lewisweller
Link to comment
Share on other sites

You earlier stated compression at 170 on all but one cylinder. Hot engine?


Unlike others, I'm no expert by any means, however, if compression is more or less equal across all cylinders but the problem affects only 5 cylinders, then perhaps it's something else.


As both banks are affected (but not all cylinders on at least one bank), then it still suggests injectors to me. You have replaced and checked all coils and spark plugs presumably?


If you're still on the original injectors at 140,000 miles, then I'd suggest running a good injector cleaner through the system, after cleaning all your new plugs. Cheap and easy.


If that doesn't do anything to resolve the situation, then at least it will shut me up (-;

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.