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)
dlynnn22

993TT Turbo hesitation

Recommended Posts

I have 1997 993TT. In 4th gear and above with the peddle to the floor at 4K RPM the turbo spools up to .8 bar, there is a sudden sputter and hesitation at 4,200 RPM. Some poppiong can be heard from the rear and the RPM will not climb any higher untill I let off the accelorator. There was a fault in the mass air meter, it was relaced; no help. New, stronger pop off valves were installed, no help. It was discovered the previous owner installed a V-Chip. An authorized V-Chip rep reconfigured the fuel-air mixture and the turbo settings. This helped for a short time. However, after letting the car sit in the garage for a couple months the problem resumed and to a greater degree. After throwing good money after bad, the porsche dealer could not correct the problem. There is an adjustable fuel pressure regulator in the car. The V-Chip representative does not think it is a fuel problem due to the O2 readings. Could this be a wastegate issue? I do not have access to a 4x4 dyno to fully diagnose. Does anyone have any suggestions?

Share this post


Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

I have 1997 993TT. In 4th gear and above with the peddle to the floor at 4K RPM the turbo spools up to .8 bar, there is a sudden sputter and hesitation at 4,200 RPM. Some poppiong can be heard from the rear and the RPM will not climb any higher untill I let off the accelorator. There was a fault in the mass air meter, it was relaced; no help. New, stronger pop off valves were installed, no help. It was discovered the previous owner installed a V-Chip. An authorized V-Chip rep reconfigured the fuel-air mixture and the turbo settings. This helped for a short time. However, after letting the car sit in the garage for a couple months the problem resumed and to a greater degree. After throwing good money after bad, the porsche dealer could not correct the problem. There is an adjustable fuel pressure regulator in the car. The V-Chip representative does not think it is a fuel problem due to the O2 readings. Could this be a wastegate issue? I do not have access to a 4x4 dyno to fully diagnose. Does anyone have any suggestions?

have you checked the coils / plugs?

Share this post


Link to post
Share on other sites

Check the operation of the distributor and that both rotors are turning.

Share this post


Link to post
Share on other sites

My car did the same exact thing. Do a compression leakdown test. Most likely you have a loss in one or more cylinders. It will be very specific when you have it tested. I had a 15% loss in cylinder #1 and sorry to say... It requires alot of work. Not too uncommon in cars that are low mileage either. Since these cars were new fuels have come a long way and carbon build up is bound to happen. If the leakdown test shows lost compression by 5% or more its time to rebuild the cylinder heads. You can try to chemically remove the build up but due to the age it is unlikely. I promise though... I had the exact same symptoms.

Share this post


Link to post
Share on other sites

A common problem is failed actuators. I had noticed that boost never seemed to reach 0.8bar (0.7 max) on mine and when the car was put on the dyno it was found to be producing only 320bhp. The power curve also showed a 'spike' at about 4000rpm where it actually did very briefly hit 0.8bar, but the pressure seemed to bleed away. Anyway, new actuators (GT2 actuators) were fitted and I've got full power back. However, I do seem to now have a slight stutter at low throttle, low rpm. Waiting for that to be investigated.

Share this post


Link to post
Share on other sites

Before throwing money at it, put the stock chip back in and see what happens

Of course the V-Chip guy isn't going to blame the chip

Share this post


Link to post
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.

Guest
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.