S6 timing

[twoqu]

Have you tried temporaily disconnecting the knock sensors at the bulkead to see if the ecu picks up a no signal fault for either or both.

[HMS-S6]

Have you tried temporaily disconnecting the knock sensors at the bulkead to see if the ecu picks up a no signal fault for either or both.

Yeh, if you disconnect either of them the ca goes into the full on limp, limiting boost to 0.4 bar so it proves nothing. Some if you connect sensors up bolted up to nothing.

[Error404]

Rich's dyno plot: obviously a while ago now but if it's always ran like this.... Doesn't seem too bad to me?

[HMS-S6]

That's the thing, above 5,000 rpm it's acceptable, just. It's anything below that it really lacks torque regardless of what the dyno read. That may have been while car car was 'in a good mood'

[twoqu]

Yeh, if you disconnect either of them the ca goes into the full on limp, limiting boost to 0.4 bar so it proves nothing. Some if you connect sensors up bolted up to nothing.

Well other than discounting a fixed 6 degree retard by the ecu!

[HMS-S6]

Well other than discounting a fixed 6 degree retard by the ecu!

I don't follw you. If it's gone into limp and more than halved boost the findings would be irrelevant

[twoqu]

If certain signals into the ecu fail then it uses certain fixed values. In the case of the knock sensors it is a retard which you claim is what you are experiencing.
But if you have unplugged them and the ecu goes to mechanical boost then we have to asume it is picking up the knock sensors.
So if it is not ignition then we are back to looking at fueling and temperature and their effect on the engine.

[UrS4boy]

G61/G66 Knock Sensor Information

If certain signals into the ecu fail then it uses certain fixed values. In the case of the knock sensors it is a retard which you claim is what you are experiencing. But if you have unplugged them and the ecu goes to mechanical boost then we have to asume it is picking up the knock sensors.

I'm not sure if I agree about what the result of failing knock sensors is exactly. I agree that without a G61 or G66 signal, the ECU will pull the timing down by 6 degrees for their respective cylinders. However, I have never read anything (well, nothing that I remember ), that says boost is pulled to mechanical only, i.e. the WGFV is told to stand totally down. There are comments that boost pressure is decreased but no necessarily to mechanical. I could be wrong.

G61 and G66 Knock Sensor info: http://forums.quattroworld.com/s4s6/msgs/21047.phtml

[newsh]

It always seems better for the first few gears after the ecu has been swapped over from one to another too.

This points to a sensor or wiring problem. When you disconnect the ecu it resets the adaptation, then you connect it again and drive on the basic map, all is well but quite quickly it adapts wrongly because of a bad sensor or a high resistance in the wiring (like the corrosion on the MAF connector) it basically adapts itself out of tune.

[prj]

That's the thing, above 5,000 rpm it's acceptable, just. It's anything below that it really lacks torque regardless of what the dyno read. That may have been while car car was 'in a good mood'

Uhm, torque looks about right for a generic chip?
Can get more with a MAP sensor swap and different software...

[HMS-S6]

Right. Replaced the female points at the MAF plug today, made no difference at all again.
Does anyone know how much of a job it is to replace the whole engine loom?

[UrS4boy]

Right. Replaced the female points at the MAF plug today, made no difference at all again. Does anyone know how much of a job it is to replace the whole engine loom?

You don't want to go there. If you are concerned about a broken loom (BTW: OE AAN looms rarely, if ever, have an issue), use a multimeter set to Ohms and some long leads to check continunity between the engine bay device, e.g. IAT, connector and the appropriate pins in the T55 connector at the ECU.

Here is the AAN pin-out that you could use as a guide. It has wire colours and the appropriate T55 pins listed:

http://forums.quattroworld.com/s4s6/msgs/21009.phtml

BTW: Do you know for sure that your cats aren't clogged, as in remove them and bypass them to see if there is a performance improvement?

[HMS-S6]

I've bypassed AND replaced them Dave. It feels like a MAF fault, boost ALWAYS stays dead steady and has no bearing of how it pulls.

[HMS-S6]

I'm literally running out of ideas now. ALL sensors are new, car is vac and boost leak free, timing is **** on. Fuel pressure is correct, exhaust is clear (new). I just don't know where to go???

[macspring]

I feel your understandable frustration from here, given how long this has been going on, years.

Find out when Prj is next coming over to England, and make an appointment with him. At this stage you've nothing to lose, and everything to gain.

Best wishes.