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tompn · 09-22-2016, 03:51 PM

I have an 06 Camelot 38PDQ with a Cummins ISL 400. The turbo doesn't make boost for about half an hour after starting a trip. I must stop, shut off the engine, wait about 10 seconds and start again and everything is fine. I have seen 35 lbs boost on the meter.

I recently met someone from Allison West in Sacramento. He presented the problem to the Cummins people there and the first question they had was about the air supply for the turbo controller. This got me thinking and I did replace the air governor a while ago. There are two air lines coming off the governor; one goes to the turbo controller and I cannot see where the other one goes. The line that goes to the turbo controller is connected to the side of the governor marked as purge. Did I get these two lines on the governor switched? Where does the other line go?

Any information and help would be appreciated. If you have one of these setups maybe you could go and look and see how yours is hooked up and let me know.

Thanks,
Tom

twinboat · 09-22-2016, 05:43 PM

The governor usually have 3 marked places for connections.

2 Reservoir, 2 unloader and 1 exhaust port

The exhaust should be open. When the governor calls for compressor pumping, it lets the air out of the unloader port.

The unloader ports go to the compressor and air dryer. If the governor is mounted on the compressor, it's connected thru the gasket. Then a line only goes to the air dryer.

One of the reservoir ports gets air from the wet tank. The governor need to sense tank air, to operate.

Since the turbo has nothing to do with the air system regulation, the other reservoir port is probably just a point the turbo control supply was tapped from.

96 Wideglide · 09-22-2016, 07:29 PM

My air dryer has a 'Turbo cutoff valve'.

Any idea what that does

?

twinboat · 09-22-2016, 08:29 PM

This is from memory, may need fact checking.

The compressor air intake is in the intake manifold. The turbo charger pressurizes the manifold

The governor stops the compressor by holding the compressor intake valves open. With no boost, the air would just go back to the manifold.

Under boost conditions, and the compressor unloaded ( valves open ), the boost would push thru the lines and out the air dryers, open, unloader port. That would cause a loss of boost.

When the compressor is pumping, the system pressure is more then the boost, so the loss is minimal.

The cut off valve stops that air flow, so you don't loose boost, and the air dryer can drain.