Jump to content

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)

Drop in RPM under hard acceleration


Recommended Posts

MY 2001 996 Carrera 2. 

I noticed a couple of days ago when i go hard on the gas pedal the tach will increase but then drop 400rpm and then go back up.  Its a split second delay when i/m hard on the gas.   Doesnt seem to do it any specific range, i've notice it in the 3000s in 3rd gear, and in the 4000s in 4th and 5th.  Today i even notice it in second gear.  

 

Any thoughts on what this is?    And if i drive it for a couple of months could i do any additional damage?

Link to comment
Share on other sites

It is a stick shift but this occurs on the highway when I am not doing a gear change. I could be in 4th or 5th and step on the gas. The car will accelerate but then there will be a slight drop in rpms and it will then accelerate again.

Link to comment
Share on other sites

I just spoke to my independent dealer and there first though is that this is clutch related and is showing the first signs.  Tehy said what could be happening is when i stand on the gas the clutch is not engaging, so there is an increase in rpms and then it engages and pull through the rpm curve.  

If it requires a new clutch, i will likely also get the IMS done.  Anyone have any thoughts on this?  How long could i drive the car before the clutch really acts up.  

Link to comment
Share on other sites

Agree with dporto. Clarification though, you said "The car will accelerate but then there will be a slight drop in rpms and it will then accelerate again." Does that mean when you give gas, engine will rev up and car will accelerate with the rev (if so, there's no clutch slipping. This is also the most likely place for clutch slipping in this sequence), then rev will drop for 400rpm and car will decelerate with that (almost like fuel cut but smoothly). Then rev will go back up normal and car will accelerate again?

Link to comment
Share on other sites

Let me try and clarify, and thank you all for the feedback.

 

When driving the car under hard acceleration (giving gas)  the rpms will increase and the car is accelerating  but for a split second during acceleration  the rpms will drop.  i  lose forward momentum, the rpms drop (400rpm) and then it accelerates again from that point forward nice and smoothly.  Not sure if i have explained it any clearer does that help

Link to comment
Share on other sites

So car and engine slow down together for a split second. That sounds more like engine bogging down for a split second as opposed to clutch slipping. If clutch is slipping, engine rev should stay high when car is not accelerating.

Edited by Ahsai
Link to comment
Share on other sites

 

Ahsai, the maf sensor has been replaced, new ignition wires, plugs, not sure on fuel filter need to double check on that.

 

It would be well worth your while to have the car tested for both correct fuel pressure and delivery as well.

 

^Good point.

Link to comment
Share on other sites

  • 4 weeks later...

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.