Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, WERE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

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)

Swapping a '99 3.4L for a 2001 3.4L Issues?

Recommended Posts

I am undertaking a small project. Swapping a bad 3.4L engine out of a '99 Cab, and replacing it with a 3.4L  2001 engine.  The main difference between the two, is that the '99 is a manual throttle and the 2001 is an electronic throttle.  There might be more, but I am not sure.  The Cab is a Tiptronic, and the 2001 engine is out of a 5 speed.  I will be removing the clutch and swapping the flex plate.


I have taken VERY careful notes, and tons of pictures of the strip down of both engines, step by step.  My plan is to replace all the parts on the 2001, with the parts off the '99, including the throttle body, intake, sensors, and fuel injectors.  I will also be swapping over the wiring harness, so the 2001 engine has the '99 wiring harness.  Hopefully, the DME in the '99 won't know the difference.


Is this as straight forward as I think it is, or are there any issues that I should be aware of and address?

Link to comment
Share on other sites

Unfortunately I can't speak to engine swaps but had seen someone did an Audi engine into a Porsche sometime ago.  Seems like they mated pretty well given their genes but a Japanese engine and German car sounds like a bigger challenge.  I couldn't help but wonder when I read your post if it wouldn't be easier to have the Porsche motor rebuilt rather than swapping or if there's some benefit I'm missing.


Another option is a company called Renegade Hybrids (or something like that) out of Las Vegas.  They do a Chevy LS1 V8 into different Porsche cars and I had ran across them back when I felt impending doom of an IMS failure on my Boxster S - which has yet to materialize.  They may be able to assist with wiring harness or adapters you need given the differences in parts but may turn out to be a square peg / round hole.  Just thought I'd throw that out there if it's of any benefit.


In any event, sounds like an interesting project and hope to see posts as your project moves along.

Link to comment
Share on other sites

On ‎11‎/‎9‎/‎2017 at 7:08 AM, mkaunitz said:

You will also have a different ECU so I don’t think you can do this as easily

Sent from my iPhone using Tapatalk Pro

Same ECU.  Swapping over all the items off the old engine, onto the new engine.  The ECU is staying in the car with the same wiring harness.  The wiring harness on the engine will be swapped over, as will all the sensors and the throttle body.  I don't believe the ECU will be able to tell the difference in engines.  Both are 3.4L, same sensors, and same wiring harness.  Am I missing something?

Link to comment
Share on other sites

The 1999 3.4 and the 2001 3.4 are nearly identical. The 99 uses a cable throttle body and DME 5.2.2 where as the 01 uses e-gas and DME 7.2. Your 99 wiring harness will also have a few extra wires for the Tiptronic change-over valve. ALL you really need to do to use the 2001 3.4 in a 1999 3.4 car is to swap the intake , throttle body and wire harness from the 99 engine to the 01 engine.(and of course remove the flywheel and clutch and install the flexplate).

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.