My 2000 honda passport consumes a lot of oil its not leaking anywere the motor is spotless. There is no were underneath were oil is leaking. But my exaust pipe has turned completely black on the in side. And it doesn't smoke or tick.

How much is a lot?

How many miles are on the vehicle?

It may be "evaporating" on you, due to the heat of the engine, and being burned--especially if you are using 5W-20 weight oil. Try using full-synthetic engine oil; e.g. Mobil 1, Pennzoil Platinum, or Amsoil. Their NOACK volitility ratings are much better and you should consume less oil, since their molecules are inherently more stable. With conventional oil, the small, light molecules evaporate first and are burned. Synthetic oil molecules are more stable and less affected by heat. I would also change the PCV valve.

The NOACK Volatility Test determines the evaporation loss of lubricants in high temperature service. The more engine oils vaporize, the thicker and heavier they become, contributing to poor circulation, reduced fuel economy, and increased oil consumption, wear, and emissions.

Synthetic engine oils resists high temperature volatilization (evaporation) better than conventional oils, helping to maintain peak fuel efficiency and reducing oil consumption and emissions.

Around a quart or a little more every 500 miles and it has about 120000 miles on it

Try using Pennzoil Platinum 5W-30, saving $15.00 in the process:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-10.html#post1924343

Unattended, the life of the catalytic converter will be greatly shortened.