Check engine light flashing and engine misfiring

[Steve_S]

Hi, first post! Just picked up my first Porsche, a 1997 Boxster and 2 problems already that would value any thoughts on.
1. Alarm started going off without cause and was able to be turned off with key remote. Then did this again 15 mins later and key remote had no effect so had to disconnect battery to silence horn (neighbors were complaining as was late at night).
Next day removed the horn fuse and reconnected the battery.
2. Started up and check engine light is now flashing and engine is misfiring and if left to idle will cut out.

Any ideas?
Thanks
Steve

[Wayne 962]

Welcome! Sorry to hear about your troubles here - they seem somewhat atypical. The alarm problems may be caused by a faulty alarm unit. The control unit is placed underneath the driver's seat, and as such, when it rains and the roof is open or leaking, water will collect in that area causing major problems.

A flashing check engine light is a serious condition that indicates a misfire (of course, you mentioned that you can hear this too). Don't drive the car in this condition, as there is the potential for raw fuel to be dumped into the exhaust, which can then ignite in the catalytic converters and cause major damage to them. The best suggestion I have is to get a code reader and see what the car is trying to tell you. See this article here: Pelican Technical Article: Reading Boxster Fuel Injection Fault Codes / Diagnosing Problems - 986 / 987

Let us know what you find out!

-Wayne

[Steve_S]

Thanks Wayne. Is there any chance the battery disconnection for many hours has caused this through loss of programmed system information for the inboard "computer"?

[JFP in PA]

No.

[Wayne 962]

Originally Posted by Steve_S

Thanks Wayne. Is there any chance the battery disconnection for many hours has caused this through loss of programmed system information for the inboard "computer"?

Very unlikely, although it does sound like you have some odd electrical problems. These types of problems are sometimes caused by burnt wiring, or even mice eating through wiring, etc. Something weird is going on. You need to pull the codes first and see what the computer is trying to tell you.

-Wayne

[Steve_S]

Took the car into the Porsche dealership and turned out to be a failed Mass Air Flow Sensor and once replaced was fine. Lesson learned however is to buy one from Pelican Parts in future as charged a small fortune at dealership. Thanks all for your advice. Steve

[Garrytw]

Steve,
Your alarm problem may be caused by your radio if it isn't the original unit, mine went off several times until I read an DIY post about grounding the alarm detection switch. Pelican Technical Article: Changing Your Boxster Stereo Head Unit / Installing Boxster Ipod Integration - 986 / 987
If not, well, as Wayne says may be something odd.
Garry