Engine speed to low

Questions & AnswersEngine speed to low
Cas Staff asked 4 years ago

I have a Sullair 1150XHH/1350XH with a compass controller driven by a C18 CAT.
The problem is that it will load up and then after a while it will shutdown with “engine speed to low”.

Diesel supply is all o.k new filters clean fuel etc,

2 Answers
Cas Staff answered 4 years ago


How long does it take before it shuts down? Seconds or minutes?

Unfortunately, I don’t have much experience with Sullair portable compressors. But I do have a lot of experience with Atlas Copco portable copressor, also with the Caterpillar engines.

Your problem reminds me of a problem I saw years ago, and also received a question about some time ago. You can see it here:


With the Atlas Copco machine it says “engine not responing”, but that error comes when the engine can not reach it’s RPM setpoint in time (in other words: engine speed too low.)

If I remember correctly, the Atlas Copco controller needed a software update and it was fixed.

If it doesn’t sound like the engine is having a hard time to keep the RPMs up, and the fuel filters are clean and the engine is running nice and quiet otherwise, I bet it is a software problem.

Good luck and let me know if you solved the problem. And any more questions, just let me know.

Austine maduforo answered 2 months ago

I want to start the compressor XAS 185 KD 7. And it did not start. Rather it showing me

1. Shut down 6420 stop failure

2. 7000 communication error.

please advice me on what to do next in order to start it.


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