Butterfly valves

[Covo71]

Probably answered before but can't find for clarification. After the blocking EGR plate there are 2 butterfly valves. Which one do you take out? Small one or big one? Cheers

[tassie wombat]

mine only had 1 I think?? and that's the 1 on the rear left hand side of the intercooler.

[Covo71]

Hi mate, I have one in the large tube and also a smaller one in the on the right hand side as you look in to it??????? I suppose it can' hurt to take out both and see what happens. Not sure what they do anyway. Cheers

[Covo71]

Any other advice? Not sure what they do. Any damage expected if I take both out?

[Rickie3]

Have a read through this http://www.nissanpatrol.com.au/forums/showthread.php?40-Blocking-the-EGR-Valve

[mudski]

Hi mate, I have one in the large tube and also a smaller one in the on the right hand side as you look in to it??????? I suppose it can' hurt to take out both and see what happens. Not sure what they do anyway. Cheers

The one in the large tube as you describe it I think controls the engine shut down. When you turn the key to off, it closes completely and starves the motor and forces it to shut down. As unlike a petrol engine where you just turn off the electrical side, you need to suffocate the engine on a diesel to turn it off. Unless I'm wrong on this part as I haven't really look into it much, or though about it, I'm happy to be told how it works. The smaller one in the Y piece is a swirl control valve. Its there to help with air fuel ratio's when the engine is cold and under 1250rpm, or there abouts. So when under those revs, half the throttle body it shut off giving the air a richer mixture for take off and once your going it opens. There is no benefit of removing this so don't waste your time. Unless you have lots of it. :)

[Covo71]

Thanks Mudski, good explanation, I have got no hair but skull is pretty thick sometimes. Thanks for the insight.