v12bug

hi
was replacing the vacuum lines on my 1999 Audi A6 2.8 30v, and am now wondering if when i replaced the vac lines, I put the vac line from the fuel pressure regulator back on wrongly - at the mo it goes straight to the EGR Vacuum Solenoid Valve (part # 026 906 283 H) via a t-piece - gold colour solenoid in pic. Should the vac-line from the fuel pressure regulator go via the non-return check valve (part # 433 862 117) blue/black valve, then onto the vacuum solenoid?

After doing the vac lines it is idling very badly / engine popping / misfiring... - without putting your foot on the gas, it cuts out.

No engine errors codes reported in vagcom, which seems a little strange.. Could someone quickly please check their vac lines for me.. many thanks

v12bug

Audi EGR Vacuum Solenoid Valve - 026 906 283 H (gold colour solenoid)

Audi Non-Return Vacuum Check valve - 433 862 117 (blue/black check valve)

v12bug

thanks guys for the replys - finally sorted out the issue with the rough idling / mis-firing etc.

I had taken off the throttle-body for a good clean, and failed to screw it back on properly with the gasket - doh!

I sprayed some intake cleaner around the engine to see if they were any vacuum leaks, and there was a significant leak around the throttle body!

Many thanks for all the tips, but just a heads up -

If you ever encounter any rough idling . mis-firing, please first check your vac pipes (replace with silicone, very cheap) and then clean and 'carefully' put back your throttle-body and do a TBA.

Engine is now running better than ever.

tcdesignguy

The fuel pressure regulator vac line goes right into the "T" fitting connection directly into the Intake Manifold. You may want to move undo the 3x 10mm bolts and move the plate out of the way to make access easy.

You also have a vacuum diagram sticker under your hood (should be on the drivers side lower) You can see where the vacuum lines go in there as well.

Steve

tcdesignguy

Whoops, didn't see that this was solved. DUH

caudillo

Where you got the silicone hoses?

v12bug

search eBay and choose vacuum hoses

caudillo

How many mm do you recommend?

v12bug

3.5mm or 4mm should do it.

If a little tight / snug at first, then rub a 'little' drop of oil on the nipple.

benhenry32

Just picked up a 2002 A6 3.0, looking for any help with vacuum lines. I found some that were disconnected and i think some are in the wrong spot. I know about the diagram on the hood, but just isn't clicking for me. if any one could post some photo's of the vacuum lines and there routing would be great. engine runs but idles bad and is sluggish.