Too high compression (Saturn)

[64conv65hard]

Wasn't sure where to ask this question so here it is. Just put a junkyard engine into my sons Saturn today. Engine only has 82k on it. Engine just didn't sound right so i did a compression check. Cylinders 1,2 & 3 were at 150 but #4 was 225. Made sure cyl was blown out, disconnected injector, blew it out numerous times but still 225. engine did not smoke at all when running and "service engine soon" light was constantly flipping on and off. Sprayed some solvent into #4 to let sit overnight with the thinking compression rings might not be allowing any blowby (carbon or stuck). Any suggestions or input would help.

 

[Jim's 70 Dart]

If it's a 1.9L normal compression is 180-205 psi. Never saw 225 psi. Check ignition coil and intake gaskets. They are the most common problems with a rough running engine. Especially the intake gaskets. Your engine is in the mileage range for a bad intake gasket. Spray carb cleaner around the intake manifold and see if it changes the way it idles. By the way every Saturn I ever worked on that had a bad intake gasket was #4 cylinder runner. Tough to dope out problems on these newer cars without a scanner.