Do I need special adapters for different diesel engines?

The TU-15B comes with one adapter. Many diesel engines use the same glow plug or injector bore thread pattern, but you may need additional adapters depending on your specific platform — verify fitment before testing.

What compression readings should I expect on a healthy diesel?

Healthy diesels typically run 400+ PSI compression, well above gasoline engines. Refer to your vehicle's service manual for exact specifications — anything 50+ PSI below spec on one cylinder usually signals a problem.

Can I use this on a gasoline engine?

No. Diesel engines operate at much higher compression pressures. This gauge is calibrated for diesel diagnostics only — using it on a gas engine risks inaccurate readings.