An phrase indigenous to the rural peoples of Norn Iron and The Republic Of Ireland.
It means things are going exceptionally well.

An attempt by plastic paddy colin murray to bring this phrase to the attention of the british public is underway.

see also the phrases "going great guns" and "cruising at 90".
nigel:"how are Armagh doing in the all Ireland?"
seamus:"jaysus they're sucking diesel so they are sir."
by DANNY August 1, 2004
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Said when you're not just feeling OK, but feeling great!
Pioneered by Colin Murray & Edith Bowman on BBC Radio 1, UK.
How are you?
I am sucking diesel!
by Andy July 21, 2004
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Restarting a diesel engine e.g. your tractor after it had emptied the tank was very difficult back in the day. There wasn't an electric fuel pump to pump it from the tank. It had to be sucked by the mechanical, engine driven, diesel injector pump. Rather difficult if the engine has no fuel to get going. Once you did get the engine running with out cutting out again you'd know it was finally sucking diesel
by Joe Lehane May 18, 2021
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Fuck me Bridie, we're sucking diesel now!
Heard predominantly in the more rustic parts of N. Ireland.
by Jimmy Ribshite October 23, 2003
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An Irish saying meaning that everything is alrite now!
"Here big lad did ya get that car going?"

"Aye I did!"

"Now your sucking Diesel!!"
by Hen D August 16, 2006
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