Hi Folks 
Does anyone know how the air that the SAI pump pumps on startup actually makes it’s way into the exhaust system?
On my car (2003 307 2L petrol RFN EW10J4) I know it goes via the big breather pipe, through a one way valve then into the side of the cylinder head closest to cylinder one (transmission end), but how does it get into the exhaust pipe from there?
I’ve had my endoscope camera in the opening behind the valve, and it appears to be a big twisty chamber going all the way along the top of the cylinder block, but there are so many obstacles I can’t get right to the other end, or see any passages leading to the rear of the engine.
Reason I ask is my car misfires badly on first starting up for as long as the pump is on, then clears up a lot when it switches off. Still has a random misfire, but nowhere near as bad as when the pump is on.
I’m thinking it may be a bad or gunked up exhaust valve in cylinder 4 (which looks like where the misfire is happening), so it would make sense if the air is being injected solely into the exhaust right behind this cylinder, and not shared evenly.
Can anyone confirm the exact path the extra air takes through the engine block?
Cheers!
Does anyone know how the air that the SAI pump pumps on startup actually makes it’s way into the exhaust system?
On my car (2003 307 2L petrol RFN EW10J4) I know it goes via the big breather pipe, through a one way valve then into the side of the cylinder head closest to cylinder one (transmission end), but how does it get into the exhaust pipe from there?
I’ve had my endoscope camera in the opening behind the valve, and it appears to be a big twisty chamber going all the way along the top of the cylinder block, but there are so many obstacles I can’t get right to the other end, or see any passages leading to the rear of the engine.
Reason I ask is my car misfires badly on first starting up for as long as the pump is on, then clears up a lot when it switches off. Still has a random misfire, but nowhere near as bad as when the pump is on.
I’m thinking it may be a bad or gunked up exhaust valve in cylinder 4 (which looks like where the misfire is happening), so it would make sense if the air is being injected solely into the exhaust right behind this cylinder, and not shared evenly.
Can anyone confirm the exact path the extra air takes through the engine block?
Cheers!
