I HAVE GOOD COMPRESSION EXCEPT FOR 1
 

1987 300 SDL 160000 NEW G-PLUGS INJECTORS,STILL RUN RUFF FOUND COMPRESSION LOW IN #1 CYLINDER...I HAVE GOOD COMPRESSION EXCEPT FOR 1 ,,THE #1 CYLINDER IS LOWER BY 50LBS I GET THE SAME READING AFTER INJECTING OIL INTO CYLINDER,ALL OTHER CYLINDERS APPEAR TO BE GOOD..I ASK YOU GUYS WHERE DO I GO FROM HERE,I SHOULD HAVE ASKED THIS BEFORE REPLACING ALL OTHER PARTS..NOW VALVE PROBLEMS??? IM WORRIED!..THANKS FOR ANY HELP RICK

post numbers
 

50 lbs is not a huge difference. What were the compression numbers. if your around 325psi or maybe a little lower it is fine. Its not optimal but will do.

What are the compression numbers?
 

Did you do the compression test with engine hot or cold? These are the spec for the OM603.

Service manual specs:
=====================
Normal pressure: 26-32 bar 377-464 psi
Minimum pressure: approx. 18 bar 261 psi
Permissible difference between cylinders: 3 bar 43 psi

It is not too far off from the spec if it is 50psi lower than the adjacent cyl. 3psi is within the margin of measurement errors. I managed to bring cyl with 50 psi and 100psi back to 300psi. So do not worry.