URS6 Way Too weak!!!

[UrS4boy]

Prj is thinking that the catalytic converters are plugged. Despite what you say about the used system that you installed was from an UrS that was "running perfect", maybe it wasn't and/or now the cats are plugged enough that they are creating a huge back pressure, causing the car to feel very sluggish because the turbo can't spin up properly. You owe it to yourself to remove the exhaust from the cat's back (on a lift, in one piece (or whatever)) so you can feel how the car responds without any exhaust restrictions. (It will be a bit loud during the test).

[prj]

Well, taking the system off can wait I guess - post up the engine bay first

Also, leave the O2 sensor unplugged, don't plug that back in.
If that doesn't give any difference - plug everything back in, then drive around a bit, and after driving around, log Group 000 with vag-com or make a screenshot of the 10 values.

[HMS-S6]

You could have also said "hmm, maybe there's something wrong with it?"

On topic:
Have you tried removing the exhaust?
Leave only the DP.

Try unplugging the O2 sensor (both heater and signal), then unplug the ECU fully for a moment and plug it back in.

I've not tried removing it, but the system (downpipe back) is again off onother car which was running perfect Is it still worth trying??

I'll definitely try unplugging the 02 sensor though and the ecu as you mentioned!

I'll take a snap of the engine bay and post it up as soon as i can.

[prj]

Also, please take a pic of your engine bay, and post it up...

[prj]

Overfuelling maybe?

You could have also said "hmm, maybe there's something wrong with it?"

On topic:
Have you tried removing the exhaust?
Leave only the DP.

Try unplugging the O2 sensor (both heater and signal), then unplug the ECU fully for a moment and plug it back in.

[HMS-S6]

Overfuelling maybe?

Very possible mate!! What kinds of things would typically cause this??

[HMS-S6]

Does the car roll freely?

Yes mate, i push it in and out of the space in the garage i keep my cars in on my own and it rolls fine.
Its hard to describe without driving it. If it were an old car with a dizzy i'd say it was way too retarded but according to vag-com its far from the case. Just feels dead lazy, even free-reving it feels ****!!

[K7ERG]

Overfuelling maybe?

[prj]

Does the car roll freely?

[HMS-S6]

That's exactly my point. That's why I said to measure fuel pressure under load.

Tested the fuel pressure under load today with two different gauges at full throttle in 3rd 4th and 5th and it was 4bar plus boost pressure on every run! Car is so so flat now out of boost range (pulling off at 1500rmp for eg) it barely pulls its own weight and feels forced under boost.

Is there anyone near-ish to me who knows their stuff willing to help??

Am i right in thinking the best next step is to obtain a WB02 sensor kit to make sure weak running is the issue??

[HMS-S6]

Unless you are relayed I really doubt that you have anything close to 14V at wide open throttle based on previous research that I and another local Vancouver UrS-club member conducted. I quote:

"As provided by the factory, this pump receives power via a circuitous route: Power from the battery (under the rear seat) is fed forward to the central relay panel under the steering column. Turning the ignition on and starting the engine energizes relay No. 6 in that panel. This sends power from the relay via a green wire to Fuse No. 17, a 20 amp fuse, in the panel on the left end of the dash. From there power goes all the way back to the fuel pump in the trunk by the ski sack in a yellow striped green wire. Based on that route, the car started and 13.5 V or so at the battery, the voltage at the fuel pump is about 12.4 to 12.5 V, i.e. a loss of over one volt. This may not seem important but because the speed of the pump is related to the voltage, the fuel flow and pressure are also related to the voltage at the pump.

While testing the fuel pump voltage while driving (via a tee-connection, 6 ft of wire, the zippered hole in the ski sack, appropriate spade connectors and a digital multimeter), I noted that voltage to the pump dropped (e.g. to 12.2 V) while driving and specifically even more so (down to 11.82 V) under wide open throttle (WOT). Sean did some static testing of the fuel pressures under simulated boost (small compressor connected to the fuel pump regulator vacuum/boost port). He found that, with the engine off, at 11.75 volts (via a switched cable from the + post in the engine bay to the right side of Fuse 17), the boost/fuel pressures were as follows: 0/57,10/65,20/72, 28/80. However, since we are running RS2 turbos and injectors and a new OEM 4.0 Bar (58 psig) fuel pressure regulator, the software wants more from the fuel pump, e.g. 0/58,10/68, 20/78, 28/86. So, since we were potentially short by up to 6 psi of fuel pressure, it was clear that at least there was a possibility that the pinging we were experiencing under WOT was potentially related to low fuel pressures resulting from low voltage at the fuel pump.

To test this more, with the engine off, Sean connected his switched static power lead directly to the battery and tested the simulated boost-controlled fuel pressures again. This resulted in 12.4 V to the fuel pump and boost/fuel pressures of 0/57, 10/65, 20/75 and 28/83. The point is that at the higher simulated boost pressures (20 and 28 psig ), the increased voltage (from 11.75 to 12.4 V) yielded an increase 3 psi. Although this was still 3 psi short of the required 78 and 86 psig, respectively, it showed the potential that directly relaying the fuel pump to the battery would help us to "turbo charge" the fuel pump and get more flow and/or pressure. (NOTE: Dave F. talked to a technical rep at Bosch USA who said that low voltages are worse than higher voltages and that the fuel pump could handle up to 16 VDC so the regulated 13.5 V from an alternator should be "no problem")." (end quote)

REF: http://forums.quattroworld.com/s4s6/msgs/24327.phtml

This photo shows the taps that I installed at the top of the fuel tank to measure voltages going to the fuel pump under different boost levels while driving:

Thanks for the link but i did all this too, just last week

[UrS4boy]

Thanks for the input. It has a genuine Audi pump in there under 500 miles ago and filer at the same time and it also has a good 14v to the pump at all times. But i will double check the pressure when i get 5 minutes.

Unless you are relayed I really doubt that you have anything close to 14V at wide open throttle based on previous research that I and another local Vancouver UrS-club member conducted. I quote:

"As provided by the factory, this pump receives power via a circuitous route: Power from the battery (under the rear seat) is fed forward to the central relay panel under the steering column. Turning the ignition on and starting the engine energizes relay No. 6 in that panel. This sends power from the relay via a green wire to Fuse No. 17, a 20 amp fuse, in the panel on the left end of the dash. From there power goes all the way back to the fuel pump in the trunk by the ski sack in a yellow striped green wire. Based on that route, the car started and 13.5 V or so at the battery, the voltage at the fuel pump is about 12.4 to 12.5 V, i.e. a loss of over one volt. This may not seem important but because the speed of the pump is related to the voltage, the fuel flow and pressure are also related to the voltage at the pump.

While testing the fuel pump voltage while driving (via a tee-connection, 6 ft of wire, the zippered hole in the ski sack, appropriate spade connectors and a digital multimeter), I noted that voltage to the pump dropped (e.g. to 12.2 V) while driving and specifically even more so (down to 11.82 V) under wide open throttle (WOT). Sean did some static testing of the fuel pressures under simulated boost (small compressor connected to the fuel pump regulator vacuum/boost port). He found that, with the engine off, at 11.75 volts (via a switched cable from the + post in the engine bay to the right side of Fuse 17), the boost/fuel pressures were as follows: 0/57,10/65,20/72, 28/80. However, since we are running RS2 turbos and injectors and a new OEM 4.0 Bar (58 psig) fuel pressure regulator, the software wants more from the fuel pump, e.g. 0/58,10/68, 20/78, 28/86. So, since we were potentially short by up to 6 psi of fuel pressure, it was clear that at least there was a possibility that the pinging we were experiencing under WOT was potentially related to low fuel pressures resulting from low voltage at the fuel pump.

To test this more, with the engine off, Sean connected his switched static power lead directly to the battery and tested the simulated boost-controlled fuel pressures again. This resulted in 12.4 V to the fuel pump and boost/fuel pressures of 0/57, 10/65, 20/75 and 28/83. The point is that at the higher simulated boost pressures (20 and 28 psig ), the increased voltage (from 11.75 to 12.4 V) yielded an increase 3 psi. Although this was still 3 psi short of the required 78 and 86 psig, respectively, it showed the potential that directly relaying the fuel pump to the battery would help us to "turbo charge" the fuel pump and get more flow and/or pressure. (NOTE: Dave F. talked to a technical rep at Bosch USA who said that low voltages are worse than higher voltages and that the fuel pump could handle up to 16 VDC so the regulated 13.5 V from an alternator should be "no problem")." (end quote)

REF: http://forums.quattroworld.com/s4s6/msgs/24327.phtml

This photo shows the taps that I installed at the top of the fuel tank to measure voltages going to the fuel pump under different boost levels while driving:

[HMS-S6]

5 years?

You're not very good at finding time
But I'd need logs from the car. WBO2, plus fast data logging, and I could at least see what's going on.

That's not going to happen without me physically looking at it though

HaHa, yeh i know, i always have waaaay too many jobs on at once!! Houses, too many cars and bloody customers!!

Unfortunately i don't have WB02 sensor and since going self employed i'm limited to vag-com and a multimeter!!

[HMS-S6]

It does seem that the issue is something on the car, if we accept that there are no boost leaks and no fault codes. Would have thought that a sensor or wiring issue would have flagged something up to give us a clue.
I am reminded of a Ur that had a fuel delivery problem. After changing the regulator, filter and pump for an upgraded one it was little better. The only remaining suspect component being the fuel tank itself. How could that be an issue!
Sourced another tank, poured some fuel into and it poured out. Done the same with the original and it trickled out! The problem was a big blob of weld where the outlet pipe had ben welded to the tank internally.
Obviously the S6 does not have such a tank but I was wondering whether there is a fuel volume rather than a fuel pressure problem. So another thing to eliminate are the actual fuel pipes on the supply side. Perhaps it has been squashed somewhere and is restricting flow. It does not explain how the symptoms would have got worse over the years though, unless the pump's performance was adequate to overcome it initially and has subsequently struggled to supply the necessary volume.
So basically I am suggesting a thorough investigation of the fuel lines!

Thanks for the input. It has a genuine Audi pump in there under 500 miles ago and filer at the same time and it also has a good 14v to the pump at all times. But i will double check the pressure when i get 5 minutes.

[prj]

5 years?

You're not very good at finding time
But I'd need logs from the car. WBO2, plus fast data logging, and I could at least see what's going on.

That's not going to happen without me physically looking at it though