Model #921.166400 pressure will not build up higher than 23PSI, what is the problem

23 psi is no where near enough to run let alone get past the regulator so no gas will return to the tank. Need 40 to 50 psi to run. So either you have a fuel leak could be in the tank or a line. Or the pump is junk

Hard to give an exact number, however, as pressure and temp of air increases, the scfm drops as you see in your numbers. With low pressure such as 0 thru 25 the temp of the air is also low/nominal thus the scfm will be very close to the actual cfm listed for the compressor pump.

Your oil pressure in every engine has to build up! What this is telling you is the bearings and oil channels have lost the oil pressure! Don't be alarmed this is a normal occurance! You can use a higher viscosity depending on where you reside? In warmer climate states a higher viscosity oil can be used like 10w30 or just 30w oil in colder climates a lower viscosity can be used like 5w or 10w generally the oil pressure taking 3 seconds to build might be the oil is due to be changed as the viscosity has been degraded or the oil pump has wear on it but as long as your pressure climbs and doesn't stay at zero you are safe if it goes above its normal position you have either a spun bearing or a stopped up oil filter not allowing the oil to travel and build up pressure!

My 2002 TDI under full throttle would peg to a lazy 13psi, then wander down.

After a computer re-map and a little tweak I'm pegging 23psi, and 18psi constant under full pedal. Fun factor increased by x10

Are you refering to the water pressure gauge near the top of the unit?

If so, during the final rinse/sanitize cycle the gauge should read between 15 and 25 psi.( flow pressure ) and is usually controlled by a water pressure regulator piped into your plumbing near the machine. Once the cycle has finished, it's normal to see the gauge register much higher pressure readings ( static pressure ) This is the water pressure being supplied to your building. Pressures of 60psi+ are not uncommon. What, I think, you're describing is normal.

All the best.

don't know what model you have. They are all pretty similar tho. Look for the regulator should have a cover on it with a single nut in the center of the cover holding it on.Under the cover is a diaphragm and a spring. tighten the adj. on the spring the compressor will shut off at higher pressure. You don't want to exceed the max rating (ie: if is suppose to shut down at 100psi don't try to go higher.)

sounds like the regulator is fualty.

Unless your machine is worn out----it's probably the pressure switch:

A: needs adjustment

B: needs to be replaced

XYZ: head gasket leak,broken line, other air leaks?

sounds like the belt is slipping have you checked the inlet and discharge valves also could be bad and leaking or stuck or installed wrong

In the majority of buildings, yes - it depends on the type of building and the building regulations. The purpose of the open vent pipe is to relieve any positive pressure in the drainage system. In buildings up to ten storeys high, one open vent is recommended to relieve the constant positive pressure build-up that can occur if the main sewer is blocked for some time. In higher buildings the positive pressure generated is in transient form, so each stack would need an open vent.