Air Compressor running ??

Regulator going bad. Air dryer.

 

You might want to check my thread: http://www.thetruckersreport.com/tr...lers/259710-is-my-air-governor-going-bad.html The following link is useful, find your particular air dryer and read the manual: http://www.anythingtruck.com/category/htp-brake-air-dryers.html Had a similar problem but my leak wasn't near as bad as yours. Check for air leaks between the governor, compressor, and air tanks. My air dryer was leaking pressure down every 4 minutes out the exhaust port. Pulled it off yesterday. Replacing today if I can locate one, or tomorrow if not. Will report back.

 

Most likely govner it's ushally on side of compressor or air dryer you can clean all this stuff by taking it apart but it's hard to get rite setting after. If you find your air govner you can also try to adjust it a bit by taking black cap of it unscrews underneath there is adjustment screw. then holding jam nut with small wrench use flat head to adjust.

 

View attachment 70889 That's your air govner

 

One thing to note with a problem like this is your air govenor pulls a pressure signal from you wet(supply) tank. Your dash gauges only show pressures in your primary and secondary tank. so the compressor can be cycling with dash gauges reading "full". one trobuleshooting tip is on the govenor there should be an extra resivoir port that you could tap a gauge into(1/8th inch pupe thread port). That gauge would show exactly how much pressure the govenor is getting and if that pressure is cycling then the comrpessor/air dryer/governor are all okay and wont be the problem. In this case some air component on the truck is using the air casuing it to cycle. one thing to do in this case is key on and use shop air to fill the wet tank so the air is always full but you can listen to air leaks with the truck off.