Strange engine noise

[PHX ATC]

This afternoon when I fired up the beast to come to work, it did a strange thing. It fired right up, idled for about 5 seconds and then it sounded as if the engine "barked" at me or anyone who was listening. The idle ( not verified by looking at the tach ) speed increased for a nanosecond and then it smoothed out.



My wife was standing in front of the truck ( I presume admiring the work of art ) and she said it sounded like someone had just unplugged a compressed air line. A big "whoosh" was what it made she said. She volunteered to fire it up next time and let me stand and listen.



Now that I think about it, it's made this funny manuever twice before and I hadn't a clue then, nor now.



Any ideas? Answers? Thoughts?



Thanks.



Toby

 

[KatDiesel]

Would it be possible it was just your engine fan kicking on?



But living in AZ, I would think its been hot enough to have it kick on before today?



Our fans make quite a racket when operating. Just a thought.

 

[PHX ATC]

It could have been, I suppose. It was around 85 degrees at 12:00 noon when I left and the "wait" light never came on at all other than when all the other lights came on.



The other two times have been in the winter when the "wait" light stayed lit for a second or two.



Toby

 

[SLightfoot]

I'll be it's.....

I'd be willing to bet anything that it's your air compressor kicking in.



I've heard this before too, and it was just the air compressor clutch engaging.



Did you have your A/C on by any chance?

 

[PHX ATC]

AAHAAA.



Hmmmm.



Son of a Sea Biscuit. I think I did. In fact, I know I did. I will try having my wife replicate the situation tomorrow and I'll stand in front of the truck and see if it does it again.



Having said that, I will be the only person in North America that will be standing in front of his/her CTD when it is started for the next 6 months, awaiting that noise.



Thanks.



Toby

 

[mike r]

Didn't lose any pets, did you?

Just kidding. But the A/C compressor will kick in with the defrosters on also.

 

[DavidC]

I live in Tempe AZ. and when my air conditioner is first turned on I hear a loud clunk and the RPM drops for a second. The first time this happened I was looking all around the truck wondering if something hit it. I never heard a whooshing sound though. This sound also seemed to only happen when parked outside in the sun and heat. When parked in the garage everything appears normal with no noise. My only thought on this could happen might have to do with the freon expansion and heat being parked outside. Hope this helps.

 

[jlccc]

Originally posted by PHX ATC

This afternoon when I fired up the beast to come to work, it did a strange thing. It fired right up, idled for about 5 seconds and then it sounded as if the engine "barked" at me or anyone who was listening. The idle ( not verified by looking at the tach ) speed increased for a nanosecond and then it smoothed out.

Toby

Toby:



Check out this link and see if your airbox got blown apart when it happened.



https://www.turbodieselregister.com/forums/showthread.php?threadid=41451



Your experience sounds like mine.

jrp