From: PJM2 [patrick.mcginnis@verizon.net] Sent: Tuesday, August 13, 2002 9:36 PM To: 928 Subject: [928] Mass Air Flow sensors- do these units deteriorate with age Fred, Talk to Kevin at http://www.injectionlabs.com/ He knows MAFs!! -- Patrick J. McGinnis 89 S4 5 speed From: A C [mailto:porsche928clubsport@hotmail.com] Sent: Thursday, May 08, 2003 4:57 AM To: 928 Subject: [928] Performance of S4's when MAF is under-reading air due to aging/wear Fred I have been looking at this for over a year now and it is definately a common problem on S2's and later cars. Over a aperiod of time the MAF degrades and the signal to the brain is slightly out. The degradation varies with the type of use, short regular journeys being the worst. As this happens gradually the owner doesn't notice the loss in performance, until they go in/drive another 928 with a good MAF. In addition it is difficult to identify a badly degraded MAF until it totally fails, as the car will still run. I have two identical 928SE's (lightweight 928S4's ltd edition), and realised that one was running much better than the other - I replaced the MAF with a rebuilt one from jdsporsche.com and the difference was stunning - I'd recommend anyone with an old MAF to get it checked. (I think the checking service was only £15). The rebuilt unit has been in the car 8 months or so and is still working fine. I also know of at least 5 other owners who have seen similar results If anyone wants further details please email me off-line. Regards Adrian Porsche Club GB 928 Tehnical Advisor From: David Chamberland [mailto:dave@inficon.com] Sent: Wednesday, May 28, 2003 12:58 PM To: 928 Subject: [928] re: Help! My car drops dead! Tad, I have experienced symptoms on my '91 which seem similar to those you describe. In my case - if the outside temperature was over roughly 80 degrees F - if the engine was at operating temperature - if the engine had been switched off for more than 1 minute but less than approximately 30 minutes it would not idle at all. The only way to start the engine was to depress the throttle all the way to the floor. Then once the engine started, part throttle was required to keep the engine idling. After about 5 minutes the idle behavior would return to normal. However, once warm and switched off, if the car sat for 20 to 30 minutes it would start and run perfectly. If the engine was cold it would start and run perfectly. For other reasons I replaced the MAS. I haven't had the above symptoms reoccur since the MAS replacement. -- David Chamberland 91 928GT (Amazonagrunmetallic: Green. NO! Blue! Ahhhhhhhhhhh!) 89 928GT (Black/Black - POS - on stands again) 928 Owners Club Charter Member (http://www.928oc.org)