11-15-2008, 04:24 AM
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#1
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Registered User
Join Date: Apr 2006
Location: Collegeville, PA
Posts: 61
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I believe those codes are for the pre-cat O2 sensors on both sides of the car. Usually both O2 sensors won't go bad at the same time. I've heard this could indicate a MAF sensor problem, but I'd search through some archives to confirm that.
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2000 Boxster S, Arctic Silver, Natural Grey Leather
Factory: Aerokit I, 18" Sport Classics, Xenons, Heated Seats, Premium Sound, and more..
Upgrades: Bumper Plugs, Door Plug, Clear Sides, Clear Tails, Clear Bulbs, Painted Bumperettes, 997 Shifter, EVO Intake
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11-15-2008, 08:15 AM
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#2
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Track rat
Join Date: Nov 2006
Location: Southern ID
Posts: 3,701
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Your car is running lean. Most often from an intake vacuum leak, bad AOS, or bad MAF.
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2009 Cayman 2.9L PDK (with a few tweaks)
PCA-GPX Chief Driving Instructor-Ret.
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11-15-2008, 02:44 PM
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#3
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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Can also be low fuel pressure or open evap canister purge valve.
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1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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11-15-2008, 04:14 PM
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#4
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Registered User
Join Date: Oct 2006
Location: Vancouver, BC
Posts: 63
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Quote:
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Originally Posted by Paul
Can also be low fuel pressure or open evap canister purge valve.
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Excuse my ignorance, but what do I do to check if its these 2 things?
Thanks.
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11-15-2008, 05:48 PM
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#5
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Registered User
Join Date: Nov 2007
Location: Ottawa
Posts: 92
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What size MAF Housing are you running. The 2.7L and 3.4L MAF's are the same part but the inner diameter of the MAF Housing is different between the two.
The 3.4L has a 3.5" MAF Housing. Get a 996 Airbox lid, cut out the MAF housing and you should be good to go.
Last edited by VRsyncro; 11-15-2008 at 05:50 PM.
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11-15-2008, 08:20 PM
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#6
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Registered User
Join Date: Oct 2006
Location: Vancouver, BC
Posts: 63
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Quote:
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Originally Posted by VRsyncro
What size MAF Housing are you running. The 2.7L and 3.4L MAF's are the same part but the inner diameter of the MAF Housing is different between the two.
The 3.4L has a 3.5" MAF Housing. Get a 996 Airbox lid, cut out the MAF housing and you should be good to go.
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Thanks for that. If the 2.7 and the 3.4 is the same part, then it shouldn't matter which one I use after the swap?
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11-16-2008, 07:49 AM
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#7
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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Check the part numbers to make sure, but I believe the MAF is the same part from 2002 and up on both 986s and 996s.
Are you running a 7.8 DME?
__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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11-16-2008, 08:05 AM
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#8
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Porscheectomy
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
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Quote:
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Originally Posted by victoreric
Thanks for that. If the 2.7 and the 3.4 is the same part, then it shouldn't matter which one I use after the swap?
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I don't know if it's true that the housings are different sizes between the 2.7 and 3.4, but if it is, that may be part of the problem. The MAF only measures air speed, to convert that into mass flow, the DME needs to know the size of the tube that the MAF is sitting in. If the 2.7 and 3.4 use different diameter housings, and you don't have the DME software matched with the right housing, it will be mismanaging fuel flow.
If the DME is programmed for the smaller housing and you are using the larger one, the computer is calculating a lower mass flow than you are actually getting and the car will run lean.
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04-06-2009, 10:36 AM
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#9
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Registered User
Join Date: Mar 2007
Location: Austin, TX
Posts: 3
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Where can I find a 996 sized MAF housing?
Quote:
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Originally Posted by victoreric
Thanks for that. If the 2.7 and the 3.4 is the same part, then it shouldn't matter which one I use after the swap?
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I'm wrestling with the same problem right now. Does anyone know the exact inside diameter of the 996 MAF housing? I believe it is 80mm or maybe 82mm?
Does anyone know of a source for a generic MAF housing that is the same size as the 996 or a 996 airbox lid that I can buy and cut the MAF housing off?
Thanks!
George
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11-16-2008, 08:09 AM
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#10
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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Quote:
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Originally Posted by victoreric
Excuse my ignorance, but what do I do to check if its these 2 things?
Thanks.
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PM sent.............
__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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11-15-2008, 04:12 PM
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#11
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Registered User
Join Date: Oct 2006
Location: Vancouver, BC
Posts: 63
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Quote:
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Originally Posted by Topless
Your car is running lean. Most often from an intake vacuum leak, bad AOS, or bad MAF.
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I've checked for intake leak and we're suspecting the MAF right now. What does AOS stand for?
Does anyone know if I need to use the 996 MAF if I did the swap? I'm using the old one from my boxster right now.
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Lil Red
2009 Porsche Cayman 2.9L
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