Possible vacuum leak
02-05-2014, 06:02 PM
#1
Cruisin'
Thread Starter
Join Date: Jan 2014
Location: New Jersey
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
Possible vacuum leak
I completed the coolant pipe upgrade in my 05 Cayenne S and all went well thanks to the excellent information on the forum. There was a rough idle after I put everything together and started the car. I could hear a vacuum leak towards the back of the engine and when I pushed on this connection, the engine started running smoothly again. I drove about 40 miles with no problems before it started running really rough again. I checked this connection again and it was still fine. I suspect that when I pushed it down the first time, it fixed a loose connection at the other end of the hard plastic tube which later came loose again 40 miles later. I smoke tested it and don't see any leaks.
Does anyone know where the other end of this tube goes? I see the rubber hose in this diagram (#28) but I don’t see the other end of the hard plastic one that runs along the firewall. I’d like to check that connection.
BTW, when the car is running (rough right now), I can disconnect this vacuum connection with no change in how it runs. I feel a vacuum on the rubber side of the connection but nothing on the plastic side.
Thanks in advance.
Does anyone know where the other end of this tube goes? I see the rubber hose in this diagram (#28) but I don’t see the other end of the hard plastic one that runs along the firewall. I’d like to check that connection.
BTW, when the car is running (rough right now), I can disconnect this vacuum connection with no change in how it runs. I feel a vacuum on the rubber side of the connection but nothing on the plastic side.
Thanks in advance.
02-08-2014, 12:13 PM
#2
Cruisin'
Thread Starter
Join Date: Jan 2014
Location: New Jersey
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
I took it for a ride this morning until it fully warmed up. It ran rough but no CEL until I got back to the garage and shut it off. I have a few pending codes for misfires, P0201 and P0301.
Any thoughts on what to check next?
Any thoughts on what to check next?
02-22-2014, 07:25 PM
#3
Cruisin'
Thread Starter
Join Date: Jan 2014
Location: New Jersey
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
The weather warmed up today so I had a chance to work on this some more.
That vacuum hose doesn't seem to be the issue. I can unplug it while the engine is running and there's no change to the rough idle.
All the misfire codes were on the passenger side cylinders 1-4. So I swapped the all those coils with the driver side ones to see if the error codes would follow the coils. Coils seemed fine (no cracks) and I installed new plugs since they were over 4 years old. No difference to the rough running.
After the coil swap, there are 2 pending codes P0201 injector circuit cylinder 1 and P0441 evaporative emission control system incorrect purge flow. The engine starts up right away, even after I open and close the gas cap (simulating refueling) so I don't think it's the Purge Valve for Fuel Vapor Canister.
I'm quickly running out of ideas. Any thoughts?
That vacuum hose doesn't seem to be the issue. I can unplug it while the engine is running and there's no change to the rough idle.
All the misfire codes were on the passenger side cylinders 1-4. So I swapped the all those coils with the driver side ones to see if the error codes would follow the coils. Coils seemed fine (no cracks) and I installed new plugs since they were over 4 years old. No difference to the rough running.
After the coil swap, there are 2 pending codes P0201 injector circuit cylinder 1 and P0441 evaporative emission control system incorrect purge flow. The engine starts up right away, even after I open and close the gas cap (simulating refueling) so I don't think it's the Purge Valve for Fuel Vapor Canister.
I'm quickly running out of ideas. Any thoughts?
