The Rowdy Audi S4 B5 - is it a dog? yes but less so as the days pass.

[DirtyDaily]

So looks like this is why the tuner missed this. My car is a bit of a mishmash of s4/rs4 components. He expected to see a VVT fault code because of the RS4 ecu software on the S4 ecu. Just so happens it is actually faulty. Sometimes knowing less actually helps diagnosing.

[DirtyDaily]

So slight update. Not as easy as i thought but on the right lines that the VVT isnt doing its thing.

I replaced the relay and no change but i have found both pins are showing 14v when it should be pin 2 being a ground controlled by the ecu. Some more diagnostics to do but i ran it up and logged the camshaft adjustment and it doesnt adjust at any point in the revs.

Therefore definitely not working as intended, supposedly should be adding 28 degrees of timing low down!

[DirtyDaily]

Another comment from a tuner based in sweden.
"Somone just flashed a rs4 image without coding it for this particular s4 configuration. All 3 codes suggest so, and obv the ecu can not see/control the vvt.
GL!"
Seems we have a winner.

[Brigsy]

Interesting stuff, hopefully be a slight software change and your away.  Is it possible to wire in and code rs4 ecu if all else fails?

[DirtyDaily]

Interesting stuff, hopefully be a slight software change and your away.  Is it possible to wire in and code rs4 ecu if all else fails?

It shouldnt really need it but yes an rs4 ecu would be fine though it would need some adjustments to the S4 loom. The ecu hardware is essentially the same though.

In other news, i have fitted a boost gauge which has helped diagnose a couple of things. On the dyno it showed the turbos only achieving 23 at redline however the boost gauge is showing 30... the turbos are working but the car isnt showing the boost and therefore the 2.5bar map sensor is wrong. I will upgrade this to a 4bar map sensor as i suspect this isnt helping. The other issue i can see of on the cam timing. Other than the VVT not activating at near redline the inlet cam is retarding to like -9 degrees from -3.5 degrees at idle. The outcome of that is the during the compression stroke the inlet valve will be open for a small time, obviously not good for power. Therefore there is probably a timing issue when the cambelt was done, the tensioner is heavily worn or the chain is stretching. We will get there eventually.

[vaughant]

600bhp aim.... Mental... But I love it 😀😀.

Being a bit older than you guys I can recall people getting 450bhp out of Cossie's as "game changing"... And you're gutted with just* 530bhp 🤣🤣🤣.

Awesome too see you guys fighting the good fight first crazy bhp 😀😀

[Westbay]

The search for power .... 😂

[DirtyDaily]

So i have spoken at reasonable length to the tuner now. I have a plan of action.

The RS4 software is requesting for a signal from both VVT solenoids, but the S4 loom only provides a 1 joint reference. Therefore the tuner suggested that i simply remove pin 115 from the ecu plug, add a spur and new pin in to position 105 on the ecu and this will bring back the VVT and he said it will also fix the top end by sorting out the inlet cam timing. Simple as that... im a bit ham fisted so i am hoping i dont cock it up. For the cost of a single ecu pin and about 5cm of wire i could gain 70hp. Power is in sight.