'04 Cayenne S 4.5 - Map sensor Value (vacuum value)

[mtr1]

Hi everyone,

I was trying to find on the internet but it is not possible. What should be the correct map sensor value at idling ? (0.2 bar = -0.8 bar?). I think I have a vacuum leak so i want to double check before i go to garage.


Thank you

[Casey at Pelican Parts]

Manifold vacuum at idle is normally in the 15-18 inches of vacuum so right around -1 bar would be expected. Checking the manifold vacuum that way however is not the best method of finding your leak. A smoke test is the best way. A smoke tester will fill the intake system with smoke, and you will easily be able to see where your leak is.

Also a good idea to check the crankcase vacuum. You'll need an adapter that you can use in the dipstick tube. Pull the dipstick and connect your vacuum gauge to the dipstick tube. Run the Cayenne at idle and you should have about 7-9 inches of water (vacuum measurement) If your value is too high usually the crankcase vent valve is faulty, too low will mean a leak in the crankcase vent lines or fittings.