She wont start

[shamierc]

On Thurs on may way home from work a huge chunk of chipboard fell off a delivery truck and shattered while on the freeway/highway...I could not avoid it and went straight over it and felt it crumble under my car...didn't seem to bad...prodded the throttle and heard that hiss indicative of a large boost leak along with the customary hesitation. Nursed the car home and found the pipe from the turbo to left cooler had been knocked loose...didn't think too much of it.

Reconnected the pipe today and tried to fire her up..she swings over freely and almost takes but then nothing...just keeps swinging over..I checked the mafs, all the piping everything obvious and can't see anything.

Vag Com gives me the following errors

17861 - Exhaust Gas Temp Sensor 1 (G235): Open or Short to Plus
P1453 - 001 - Upper Limit Exceeded

17740 - Knock-Control: Cylinder 8: Regulation Limit Exceeded
P1332 - 001 - Upper Limit Exceeded - Intermittent

17735 - Knock-Control: Cylinder 3: Regulation Limit Exceeded
P1327 - 001 - Upper Limit Exceeded - Intermittent

17739 - Knock-Control: Cylinder 7: Regulation Limit Exceeded
P1331 - 001 - Upper Limit Exceeded - Intermittent

17473 - Fuel Pressure Regulation: Regulation Discrepancy
P1065 - 008 - Implausible Signal

17734 - Knock-Control: Cylinder 2: Regulation Limit Exceeded
P1326 - 001 - Upper Limit Exceeded - Intermittent

17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 001 - Upper Limit Exceeded

17538 - Fuel Trim; Bank 2 (Mult): System too Lean
P1130 - 001 - Upper Limit Exceeded

I know before the incident there were no fault codes. Im thinking its a fueling issues, maybe the fuel lines under the car got damaged..the fuel guage shows a quarter tank and i can't see any damage to the lines...there are scratches on the tank though...

any Ideas?

[Shoppinit]

That's a weird one. When you clear the faults, what comes back?

Does sound like a fuel problem. Other than the EGT code, they are all linked to not enough fuel getting to the engine. Possibly one of the fuel pumps was damaged? Or the wiring going to it. Check the external fuel pump and connections first. After you'll have to start diagnosing the fuel supply system more thoroughly.

[Shoppinit]

Check that, when cranking, the fuel pumps are supplied with approx 12V which then drops to 10V after a few seconds.

Also have a look for damaged earth connections.

[JCviggen]

This is a tough one. I'm going to go out and say that no way all those faults will trace back to a single problem.

EGT sensor code seems like it could be damaged (or the wiring)

The rest seems like a fuel problem obviously, and that is almost certainly the reason it's not starting.

You need to check the fuel pressure really and take it from there. Odds are it will barely register. I don't know exactly what the fuel lines look like on the RS6, never looked at them, but it would be obvious if you were losing fuel somewhere. But the line may have been compromised (taken a hit and pinched shut in case of a metal line) or you could have a pressure regulation issue of some kind. It's a bit strange that the car would continue to run all the way home with this fuel issue, but if it's just borderline it's possible (and would prevent you from successfully cold starting which needs more fuel)

[shamierc]

Thanks for the responses. Cleared the codes and only the coolant fan code came back...but the car hasn't run since so can't really assume any have been resolved. Based on above I plan to buy a fuel pressure gauge tomorrow and install it...will see what it registers..but as per above im not expecting it to show anything...

[shamierc]

So I deserve a darwin award or something

Rechecked everything again...then I thought..."what if the fuel gauge is faulty"...then thought..."naaah...what are the chances"...decided to put 5 litres in anyway and test....

She fired right up...

I guess the reason for the fuel starvation was a lack of fuel...I think i've just dropped a few notches on your guys scale....

[PhilT]

The shame of it . At least you admitted to it.

[shamierc]

Situation has gotten weird...

On sat afternoon i took the battery out and put it on a charger overnight as all my attempts at starting were taking their toll...put it back yesterday and got her started...with fuel...but now the gearbox is very wonky...slipping occasionally...taking really hard and hunting for gears...

Not cool...hope its just a software thing...

[JCviggen]

You can expect the gearbox computer to take a bit of time to learn after it has been disconnected from power. How "bad" it could get after a reset I'm not sure about though. I noticed mine was a little weird when I picked it up after a box rebuild, took a few hundred miles (mainly highway though so probably not a good example) to get back to normal.

[Shoppinit]

decided to put 5 litres in anyway and test....

She fired right up...

Shame on us for not suggesting it

[shamierc]

Started looking at the gearbox issue.

She went into gearbox limp mode on my way home from work....at 3am.

Seems she's slipping but I think its not anything mechanical wrong with the box. Used Vag Com to measure blocks 1, 2 and 3 on the transmission controller with my foot on the brake with the car in D, R and N.

For all 3 engine speed is 750rpm

D and R has input shaft at 0 rpm which indicates the slip is because the clutches are getting a "signal" to slip...so will be testing the solenoids and then will as a first pass perform a fluid flush and filter changed

As noone at the Audi Club SA has really debugged and investigated tiptronic box issues I have created a purpose built thread to record my experience to avoid others paying school fees when I have already..

thread here -> http://www.audiclubsa.org.za/cgi-bin/ya ... 1319540977