Does a 120# really suck? The others are 130-140. Everything is OK besides the #'s.

 

What year/derivation of 944 do you have? Generally speaking, consistent numbers are more important than high numbers, but 120 in one slug is definitely low. Just checking, you did this with a warm engine, pulled the DME relay and you propped open the throttle plate, right? Assuming the answer was yes, you should do a leakdown test to find out whats really going on. How is your oil consumption?

Regards,

 

'86 all stock engine. 120, 135, 140, 130. Yes all those were done during test, but I don't recall if he DME relay was pulled... what difference would that make? No oil consumption. Good power. Had to forego the leakdown test because we ran outta time with a couple of extras I added. I did one of those detergent runs there to hopefully(maybe) clean out any carbon in the valves. Soon I'll see if that did anything, then do both tests one last time. If it's a solid 120, how long till I start doing some damage, or have to tear it apart? Could be 1000 miles or 10,000 miles right?

 

Its just as important to not "overdiagnose" problems when looking at these sorts of things. I see WAY too many people start troubleshooting one problem and wind up creating a bunch of problems for themselves along the way. You've got good power and no oil consumption, so I wouldn't be in a rush to do much of anything yet. Run a BUNCH of Techron through the engine and take it for some good spirited runs where you can keep the rpms up for a while. Carbon deposits can cause low compression readings, and since your readings were all over the place relative to each other, I hope thats what you have. I'd still suggest that you look into a leakdown test before too long, just to check it out.

Oil consumption is the one I would watch for. If you are burning more than a quart per 1000 miles, then you need to be checking closer.

Regards,

 

with 951...which is 8:1, psi should be right around 150. now with my 89 which has 11:1, and other n/a which are 9:1 and 10:1, psi should be higher. yes, more important is the similiarty in psi numbers across all 4 cylinders, however when you're running psi in the 110's, etc, it's time for a rebuild.