Instead of looking for a specific number, focus on these crucial points:
* Consistency is Key: The most important aspect is that the compression readings across all four cylinders are within a relatively small range of each other (typically no more than 100 kPa or 15 psi difference). A significant variation indicates a problem in one or more cylinders (worn rings, valve problems, etc.).
* Minimum Acceptable Reading: While a specific number is elusive without a manual, a generally accepted *minimum* acceptable compression reading for most engines is around 90-100 psi (620-690 kPa). Readings significantly below this suggest engine trouble.
* Consult a Service Manual: Your best bet is to find a service manual specific to your 1994 Mazda 626 LX 2.0L. These manuals will provide the manufacturer's recommended compression specifications and testing procedures. You can often find these manuals online (sometimes for a fee) or at auto parts stores.
In short: Don't rely on general online compression numbers. Check for consistency between cylinders, and compare your readings to the specifications in a Mazda service manual for your specific engine. If you have inconsistent readings or numbers consistently below the minimum acceptable range, you likely have a mechanical issue requiring professional diagnosis.
