FS:1986 Porsche 944(N/A)-$1300*UPDATED with pics*
#49
Nordschleife Master
When posting use the image insert button square button with a picture of mountains), or insert IMG in brackets.. if you just insert the link to the pictures, the system recognizes them as URL refferences..
All I did was change URL to IMG and the images embedded..
All I did was change URL to IMG and the images embedded..
#50
FYI: I don't claim to be a Porsche mechanic, but my 84 944 (~160K miles) recently failed smog with high NO (~2000), and rather than pay someone to dianose the problem, I took it on as a learning exercise. I first paid a muffler shop to replaced the CAT with a California legal one (~$300.00). That helped slightly, but the NO was still around ~1500. Through lots of searching on the web I learned that high NO are caused by a lean running motor and the Mass Air Flow sensor (that large metal and plastic thing connectred to air filter box) was responsible for determining the air fuel ratio (lean or rich mixture). I also learned that the O2 sensor could be used to determine how rich or learn the motor was running and that a reading of ~.6 was about right. Not knowing if my O2 sensor was still good I decided to replace it with an after market universal one (3-wire ~$40.00 online). With the new O2 sensor replaced (which, by the way was an easy job), I measured the O2 reading with the car at normal operating temp. and found it to be ~.1 (lean mixture) much lower than the ideal .6 . I then pryed the plastic cover off the MAF sensor being very careful not to damage it and inspected the inside. I very carefully bent the wiper slightly to move the dual contacts to a new location on the resistor track and using PCB flux remover sprayed the entire inside to clean any foreign material off the track, wiper and the pads where the two external pins make contact with the ceramic board. I than rotated the position of the large black dial (with numbers on it) that provides the spring tension one notch counter clockwise, reducing the spring tension slightly to compensate for an aging MAF sensor. Reassembled everything and started the car, ran it up to temp and measured the O2 sensor (disconnected). The reading was varing between ~.68 and ~.80 . I attempted to adjust the MAF sensor bypass (using a allen wrench), but it did not seem to make any difference in the reading. I took the car out for a test drive and it seems to run very well. Before all this it would stumble at low RPM's, especially when cold, and now it seemed to have more low end torque and it did not stumble. I had it smogged and it passed with surprisingly low NO, under ~200 (a factor of 10 reduction). The guys at the smog shop said I had one "clean" car. I'm happy. I learned a lot about my 944 and it only cost me about $340.00, which I consider to be a steal.
#51
Rennlist Member
yeah if you search you will find a few posts about cleaning up the slides in the afm. Our old 924s had the same issue. You can also relieve some spring pressure from the afm and it will respond alittle faster.