Understand that, I had a problem meeting CA Smog Checks back in the ‘80s. I sent my pump and injectors to a service shop in South San Francisco. He worked for Bosch in Germany when Porsche was still building cars with Pump type MFI. He had two Pump/Injector test stands. At that time there were three places in the US that worked on the pumps. New Jersey, South San Francisco California, and somewhere in between. I picked up the pump in person and he was a very personable guy. He walked me through the whole process of overhaul and calibration. I wish I could recall his name. A very German name.
I would have thought that with all the MFI equipped cars driving around the Alps to the sea shore it would be close. But the Barometric aneroid is probably past its design life.
At the time, his tune worked for 100k+ and 10 years without a hint of a problem.
I didn’t have enough experience to make adjustments to anything on the rack other than the idle mixture. I imagine that with familiarity one could wing-it. I guess the adjustment would be pretty linear.
What I found amazing, was the throttle response.
Quote:
Originally Posted by Jeff Higgins
In my experience across several cars fitted with MFI, the barometric cell has a pretty limited range of compensation. I have yet to see one that can compensate for a 5,300 foot change in elevation. Oh, the car will run across that variation in altitude, but not optimally. It's best to readjust the pump, especially if we have moved from a high altitude home to a sea level home, or vis versa.
We do that by adjusting the main rack, not the idle mix adjustment. I probably wouldn't even bother with the latter, it gets completely overwhelmed by the main rack adjustment.
The main rack adjustment is behind the allen bolt to the lower right of the warm up solenoid. It is best accessed with the speciality tools available for this, the long t-handle allen wrench and the long, very fine tip flat blade screwdriver. Snake them in under the coil, to the left of the fan shroud.
The warmup solenoid is unaffected by changes in altitude. Don't even bother looking at that.
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