andrew1

I accidently made a thread into a wrong topic so here it is in a right place

I bought myself an audi 80 2,8 wich had a problem with the engine. It was lacking power,basicly up to 2500rpm it revs quite fine and after that it just gets even more dizzier. But even on the lower rpm's it's still not good as it supposed to be.
I checked the trouble codes and these are what I got:

After checking the MAF and deleting the codes none of them existed so I started looking for vacuum leaks. I found some but after fixing them nothing changed, then I noticed that the intake flaps doesen't move. If i move them by hand, they're moveing well but the vacuum is not doing anything. Next on I starteg going by the line and found a solenoid valve on the air filter box, wich should lead the vacuum to the intake flaps. The solenoid klicks, if I lead the power on to it and changes the way air is moved so it should work.
But my main concern is that how much vacuum is supposed to come from the vacuum reservoir, I connected the reservoir directly to the intake flap line but they still didn't move... So is the reservoir leaking or why isn't there enogh vacuum? Or these thing are fine but there are other issues? I'm quite new on the V6 so I could need some help.
Andrew

Oh, therese a picture of the solenoid, and how the cables run:

The dark blue one, further away goes to the intake flaps and the yellow one comes from the vacuum reservoir.
I hope I made my problem as clear as possible but don't hesitate to ask some more questions.

Rusty Spokes

Those black/blue check valves can fail..plug up. Easy to check. Remove it and try and move air by blowing/sucking on the valve.

I've had a few go bad and not supply vacuum when needed. About a $3 part.

The black side of the valve always goes towards the vacuum source.

http://www.hansautoparts.com/4338621...heckValve.aspx

This forum is very sleepy..let us know how it goes.

andrew1

The valve works fine, I also changed all the vacuum lines(3,5mm)but nothing changed. The car is in the diagnostics right now, hopefully on saturday I'll find out what's going on. So I'll let you know, right now this problem is too complicated for me.

Rusty Spokes

Vacuum motors, lines and valves can be tricky. You need a tool to help. Look around and find a hand held vacuum pump. Using one with a gauge and test your lines and valves, solenoids etc.


Remember the big vacuum reservoir in the system takes a while to pump down with a hand held pump. Disconnect it and test it while going though the system.

andrew1

Found the problem - its not even becouse of the vacuum but the knock sensor(s?). The engine control unit didn't change ignition time more earlyer so this is the reason my car didn't rev up well. I'll tell you more, if I get the car back and talk to the diagnistic guy, who found the problem.

andrew1

basicly I need new knock sensors, can anyone tell me, if 2,6 sensors are the same with 2,8?(AAH & ABC)

Also, where i can check the part nr's myself?

andrew1

Yes, they are the same. Hopefully someone else someday needs to know that

Rusty Spokes

My local Audi dealer has the parts catalog online:

http://www.jimellisaudiparts.com/sho...knock%20sensor

Should be part numbers 054905377G for the blue knock sensor or if the originals are green in color 054905377A

About $93 each from Audi or $9 each for the blue sensor or $7 each for a green sensor from HansAutoparts. I'm sure there are two on your engine.

http://www.hansautoparts.com/0549053...Fatj7AodxioAog

You may want to check and see if the green knock sensor(s)are an updated part..seem I remember something about using the green as a replacement.

andrew1

The green one is for the drivers side of the engine and the cable is longer. but thats the only difference it has form the blue one. Right now I got two used sensors(audis original) and next week I'll replace them. Hopefully this solves my problems with the engine.

CRAZY_RUSSIAN

try tightening down you intake... i head something simulator after a top end rebuild