Date: Sun, 29 Oct 2000 22:43:57 GMT From: "Keith Grider" <nospamnopsamdnet.att.net> Subject: Re: Acceptable compression reading 900 T16
John, 14.7* the compression ratio is the maximum you can expect. Verify what the drop from this theoretical average is. I don't think this would be the problem. It is usually much simpler. If it is not burning oil and it idles smoothly, it may be cured by a simple tune up (plugs, clean throttle body, verify no vacuum leaks repair if necessary). If it is still off, replace the o2 sensor. Hey, these are only 40.00 and according to saab have 60kmi of life. If it is over 100kmi on the original o2, it is probably in need of replacement. Keith Grider "John Griffin" <johnnopsamfinphoto.u-net.com> wrote in message news:B620BC18.3667%johnnopsamfinphoto.u-net.com... > I am about to do a compression test on my 85 900T16(193K miles) - economy > has fallen off a bit recently from 36 mpg at a steady 70mph to around 27 mpg > - everything else checks out OK tune wise and there are no flat spots, idle > or power problems. > What is an acceptable pressure reading on the cylinders - I know Saab don't > give any figures for this but I would like to hear from those who have > tested good and tired engines. > > Regards > > > John >