Pelican Technical Article: Throttle Body Replacement / Cleaning Intake & Boots Wayne R. Dempsey
Time: 3 hrs
Tab: $15
Talent:
Tools:
Torx driver set
Applicable Models:
986 Boxster (1997-04) 987 Boxster (2005-08)
Parts Required:
New o-ring or idle control valve gasket
Hot Tip:
Remove the throttle body and let it soak in carburetor cleaner overnight
Performance Gain:
Smoother running engine
Complementary Modification:
Replace intake plenum boots
This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your Porsche Boxster. The book contains 312 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 950+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Boxster owner's collection. The book is currently available and in stock now. See The Official Book Website for more details.
Check out some other sample projects from the book:
The Boxster throttle body is a precision piece of equipment that is subject to a rather harsh environment. After years of reliable service, the throttle body may become dirty or clogged, which may result in lowered performance. You may find that there is a lot of built up dirt, particularly if a previous owner didn't change the air filter too often (Pelican Technical Article: Air Filter / Pollen Filter Replacement). Instructions on how to access the throttle body are detailed in Project 83 (starter replacement). Remove the throttle body (yellow arrow) from the intake plenum and then take it over to your workbench and clean it out using some carburetor cleaner. Run lint-free cloths through all of the passages and make sure all the dirt and debris is removed. The blue arrow shows the intake plenum boots that should be checked for cracks and/or replaced after many years of use.
This is what your throttle body should look like after you've finished cleaning it. Shown here is the early-style cable throttle with the idle control valve (green arrow). This valve controls the air that passes by the throttle: if it's clogged you will get erratic idle and warm up problems. Be sure to use a new gasket when you remount the idle control valve to the throttle body. With the throttle body completely clean, remount it to the intake plenum using a new rubber gasket (yellow arrow, inset photo).
Clean out any oil and debris from the inside of your intake plenum, and replace the rubber hoses / boots if they are old or cracking. This photo shows the inside of the intake plenum on my Boxster project car, which had a disastrous engine failure. Those small pieces of metal that you see there are leftover piston rings! Normally, you will only find oil and gas residue in the intake plenum. If your air-oil separator has failed, then you will indeed find plenty of excess oil in here and also coating the throttle body that needs to be removed.
Comments: Just cleaned my 2000 Boxster TB. It doesn't take a valve gasket nor intake ring. Instead it has electronics attached which you should leave alone and the ring is built into the intake. The intake is a bear to get back on but w/ a little grease and some strength it gets there. Idle improved alot.
April 21, 2012
Sak
Comments: Hi, recently my check engine light came on, in my 99 boxster. For several weeks prior to that, my idle was irregular, it would fluctuate, not wildly but enough to notice. It would usually go from 800 to 1200. I attributed this to cold startups, but now am wondering if this could be a possible reason why the CEL is on.
Comments: I have a 2000 Boxster which has the newer electronic throttle built into the throttle body. I'm getting a ODBII code PO507 that is telling me the Idle Air Cotrol is bad. Based on this article I don't think my car has an IAC? Can you clarify? Idle is eratic and check engine light is blinking.
June 26, 2011
Followup from the Pelican Staff: On cars with the electronic throttle body, the idle air is controlled by the computer opening and closing the throttle slightly. So, there may be an issue with the actual unit, or it may be that it's dirty or clogged. I would clean it first (see the article in our tech articles section on this) and see if that improves the performance. I suspect it will. Also, if it's really dirty or clogged up, keep in mind that this is unusual, and that something odd must be causing the clog. It might be a bad air filter, or a failing air-oil separator. - Wayne at Pelican Parts
RickE
Comments: Thanks for writing back. I took it to a shop a couple weeks ago and they found the oil dip stick tube had a crack and there was a bad relay in the emmissions system. Now it is running great. If I had had the book I might have been able to fix it myself. Will it be out for Xmass?
Thanks, Dave
November 29, 2010
Followup from the Pelican Staff: Looks like the book will be out in late December 2010 or early January 2011! - Wayne at Pelican Parts
RickE
Comments: Hi,
I am having a big problem with my idle surging up to 3K and back down again over and over. It makes the car very hard to drive when it does this. When the car is cold it starts up and runs like a dream. If I don't shut it off it keeps running fine. If I shut off the engine and restart it I get the wild surging engine. It is like I am depressing the peddle over and over. It will not go back to normal until next cold start. I was going to try cleaning the throttle body and want to order the gaskets as listed above. When I go to the parts for this project page it shows the mass airflow gasket but not the Idle control valve rubber gasket. What is the part number? I have a 2004 Boxster 2.7. Can you think of anything else I can try? Thanks, Dave
October 21, 2010
Followup from the Pelican Staff: This is typically a mixture problem called "hunting". It's very symptomatic of a vacuum leak in the system. I have an article on checking for leaks right here: http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm As for the gaskets, if they are not listed in the catalog, please give our sales dept a call at 1-888-280-7799 and they can assist you with tracking them down. - Wayne at Pelican Parts
Check out some other sample projects from the book:
