EGR BPT Valve

[A1218]

So I haven't tracked down the very occasional rough hesitating idle that occurs for a few seconds after a warm start. I did a smoke test on the engine and found that the EGR BPT valve (the one behind the EGR valve) was leaking smoke when testing.

Is this valve supposed to be open to atmosphere when engine is off because of no pressure? I've read that online but not sure.

You hear a hissing noise as if there is a vacuum leak when engine is on. And when doing smoke test with engine off that was the only thing leaking smoke.

leads me to think that is bad and can be causing the issue on start occasionally.

Any ideas?

[04pathse]

found this on a quick search

Have you tested the BPT? It's very simple, but you will need a vacuum pump. Simply plug one of the top 2 ports (I used a rubber cap, a finger may work), put a clean tube on the bottom port and a hand held vacuum pump on the other top port. On the bottom port, gently blow air into the tube, then apply vacuum with the pump. Once the vacuum is applied, the vacuum should hold steady as you are blowing. If the vacuum starts to get lower, then the BPT is leaking.

[fontana dan]

Hello did you fix this? Having same symptoms on my Q45 which has the same part. Smoke leaking from circular valve during test with engine off, P0171, vacuum hissing noise under the hood, hesitation while driving...
Ordered a new one on Ebay OEM p/n: 1474102E00

[A1218]

I just changed the part, but my issue was not stemming from that. The rough hesitation was from the pressure regulator.

[VStar650CL]

Low fuel pressure will cause P0171 too, but I'm surprised you didn't have performance issues and not just a cold hesitation.