Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 02-28-2016, 08:03 AM   #1
Registered User
 
JonnyReverb's Avatar
 
Join Date: Dec 2015
Location: Ohio
Posts: 5
Air Intake -40 Degrees

Hey Everyone,
I have a 99 Porsche Boxster with 64K miles. The performance has gotten pretty bad, and the check engine light came on, so I took her to a mechanic someone recommended. They said the mass airflow sensor is reading -40, the mechanic hooked up a new one (Bosch), and the temp was still -40. There was also a code that coil 3 misfired. I am guessing the two are related (maybe the low temperature reading is causing her to run rich). But if it is not the MAS, I am stumped.
I ran a search in here and on Google with no results. Anyone seen this before?
Thanks,
Jonny

Last edited by JonnyReverb; 02-28-2016 at 08:17 AM.
JonnyReverb is offline   Reply With Quote
Old 02-28-2016, 08:38 AM   #2
Registered User
 
The Radium King's Avatar
 
Join Date: Apr 2010
Location: Canada
Posts: 2,887
i'll take a stab. there is an iat (intake air temperature) sensor that plugs in to the intake manifold. this is where the computer gets it's air temp info from. if it is unplugged, shorted to ground, covered in goo, or just failed, it might be sending a signal so far out of whack that the computer is just defaulting to a minimum value (-40). the iat sensor is #17 on the diagram below:

Intake Distributor
The Radium King is offline   Reply With Quote
Old 02-28-2016, 08:55 AM   #3
Registered User
 
Join Date: Feb 2005
Location: It's a kind of magic.....
Posts: 5,095
Quote:
Originally Posted by The Radium King View Post
i'll take a stab. there is an iat (intake air temperature) sensor that plugs in to the intake manifold. this is where the computer gets it's air temp info from. if it is unplugged, shorted to ground, covered in goo, or just failed, it might be sending a signal so far out of whack that the computer is just defaulting to a minimum value (-40). the iat sensor is #17 on the diagram below:

Intake Distributor
Hate to have to correct you, but that is the engine compartment temperature sensor; the intake air temp signal comes from the MAF.
__________________
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
JFP in PA is online now   Reply With Quote
Old 02-28-2016, 08:59 AM   #4
Registered User
 
The Radium King's Avatar
 
Join Date: Apr 2010
Location: Canada
Posts: 2,887
my bad! thanks for the info. cheers.
The Radium King is offline   Reply With Quote
Old 02-28-2016, 10:06 AM   #5
Ben-Auto-Design
 
Ben006's Avatar
 
Join Date: Oct 2014
Location: French Riviera
Posts: 801
A problem in the wiring ?
__________________
ASE certified Automotive Master Technician.
Porsche Tech in France.
www.benautodesign.fr
Ben-Auto-Design : Performance parts for 9X6 / 9X7
2001 986 S, Manual, all black.
Ben006 is offline   Reply With Quote
Old 02-29-2016, 04:58 AM   #6
Registered User
 
Xpit77's Avatar
 
Join Date: Jul 2014
Location: Canada
Posts: 454
While were talking mafs mine threw a code a few days ago. P0102. I cleared it. Waiting to see if it returns. I have`nt cleaned it in the almost 3 yrs that I`ve had it. I started to source a new one did`nt know the price. Why is there such a swing in the price of them ? I know dealer is well. But online from $ 50 to $600. WTH ?
__________________
99 Boxster 88 944S sold
Xpit Formula Four sold
95 Integra Solo I sold
71 Opel GT sold
63 MG Midget sold
Xpit77 is offline   Reply With Quote
Old 03-17-2016, 06:52 PM   #7
Registered User
 
JonnyReverb's Avatar
 
Join Date: Dec 2015
Location: Ohio
Posts: 5
The mechanic hooked up a new Bosch MAF, and said the readout was still -40. I cleaned it and cleared it, and it just came right back. Anyone know where I would start for the wiring?
Thanks,
Jonny
JonnyReverb is offline   Reply With Quote
Old 03-17-2016, 06:56 PM   #8
Registered User
 
JonnyReverb's Avatar
 
Join Date: Dec 2015
Location: Ohio
Posts: 5
Quote:
Originally Posted by Xpit77 View Post
While were talking mafs mine threw a code a few days ago. P0102. I cleared it. Waiting to see if it returns. I have`nt cleaned it in the almost 3 yrs that I`ve had it. I started to source a new one did`nt know the price. Why is there such a swing in the price of them ? I know dealer is well. But online from $ 50 to $600. WTH ?
Yea, I noticed the crazy price range online too. $250 from Bosche, $500 from Porsche, or $50 from China...
Let me know how it goes if you pop one in.
Thanks,
Jonny
JonnyReverb is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 02:54 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page