Testing warm up regulator
 

1991 964 turbo hard starting when hot...I am testing the WUR, I get 3.9 bar when cold 5.9 bar when hot. This seems like high pressure when hot..I do not have any books to give me specs..What do you guys think?

Just took a look at the manual, these numbers are too high...should be:

Cold (@ 20 deg c) should be less then 3 bar
Hot control pressure 4.5 (+or- .2)

Thanks, I finally got the books, boy you can't do anything without them!! Altitude adjusted pressure worked out fine. Problem was related to the Air flow Sensor plate height!! My mechanic finally removed it and shimmed the lever with a couple of washers and voila problem solved. No one came close on that one!! We are talking micro adjustment...