S6 timing

[prj]

It's no myth.

It is on this ECU.

I totally hear what you're saying but I've had this serveral times now. Is it possible that it is not acting on wot and trying to stay in lambda control?

Impossible. Lambda control and fuel trims are disabled over ~70 load on this ECU. Your load values are 190. So it's 100% off.

Your problem is nothing to do with electronics, your problem is an intermittent mechanical one.
Maybe digital logging of fuel pressure together with AFR at all times would be helpful.

[prj]

http://www.14point7.com/products/sigma-lambda-controller-diy-2

Fuel pressure logging, AFR logging, RPM logging on same graph using WinLog.

[HMS-S6]

It's showing 99% and am getting correct boost but yes it's as if it's not switching to wot.

[prj]

It's showing 99% and am getting correct boost but yes it's as if it's not switching to wot.

There is NO wot switching in this ECU.
The only thing that is used is the absolute throttle position. If it is showing 99 then its WOT, anything over throttle position about 85 is from a mechanical standpoint.

It does not make ANY difference for the ECU though. It does not care where your throttle is apart from boost control for the target pressure, all fueling and timing is done off of the MAF.

[HMS-S6]

Sorry. I think my replies are delayed Dmitri.
The problem is still only under full load (2,500-3,800). Since having I nice exhaust made, at this point the exhaust tone sounds horrid, not like a 5cyl. No like a typical misfire sound but almost like an off beat thunder sound then as it passes 4,000 it richens up and sounds lovely.

[HMS-S6]

The boost readout on the dash is still 0.1 bar above the mechanical gauge most of the time too. When you look at the atmospheric pressure this does not add up to atmospheric plus boost. With just ignition on it reads 1.1. Both ECU are doing this and running is worse when this condition is present.

[UrS4boy]

G71 Manifold Absolute Pressure (MAP) sensor info

The boost readout on the dash is still 0.1 bar above the mechanical gauge most of the time too. When you look at the atmospheric pressure this does not add up to atmospheric plus boost. With just ignition on it reads 1.1. Both ECU are doing this and running is worse when this condition is present.

To me 1 Bar = 14.5 psig. Atmospheric pressure is around 14.7 psig at sea level. As a result, atmospheric pressure, in Bars, absolute = 14.7/14.5 = 1.014 Bar so 1.1 Bar is a bit more than simply rounding up error but only a 8.5% error (max.) (BUT rounding to a 1.1 display reading could be from 1.051 bar actual reading in which case the effective error would be 3.68%). Not sure what the level of precision of the OE Bosch MAP sensors is supposed to be.

You might want to replace your MAP sensor, if only to remove it from the equation.

G71 Manifold Absolute Pressure (MAP) sensor info:

http://forums.quattroworld.com/s4s6/msgs/20417.phtml

[newsh]

My mechanical gauge also reads between 0.1 and 0.2 Bar lower than the map sensor in the ECU when the engine is running.
I'm not sure the reading on the dash is valid unless the engine is actually running.


I can't remember, have you checked your atmospheric pressure sensor?

Also suggest you cut the end off the vac pipe at the ecu and remake the joint? The hose can go hard so it leaks even when the clamp seems to be tight.

Take the cap off the WG and check the valve pulls up and down freely, no sticktion, make sure the diaphagm is centred. I did this on the coupe the other day and it runs much better.

[newsh]

You might want to replace your MAP sensor, if only to remove it from the equation.
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Both map sensors in both ECUs?

[UrS4boy]

Both map sensors in both ECUs?

Then ignore my suggestion (as usual ) and look elsewhere and don't worry about the digital gauge error. Get an analogue boost/vacuum gauge. Check out hunker7's thread for boost gauge options that I posted recently.

[twoqu]

As the boost measurement signal is an output from the ecu I doubt whether it is having any effect. The fact that both ecu's display the same indicates that whatever calcucates the display is just a bit out.
Whatever this issue is, it is not consistant with a marginal increase in boost pressure.

[newsh]

Then ignore my suggestion (as usual ) and look elsewhere and don't worry about the digital gauge error. Get an analogue boost/vacuum gauge. Check out hunker7's thread for boost gauge options that I posted recently.

Dave it's not my car and I was only scrating my head.. Can you see a scenario where bot ECUs have the same small error? And he's already got an analogue gauge, that's what he's comparing with.

[HMS-S6]

It is still going in on the 21st, this was literally just an observation I made today. The one thing 100% consistent is that when the car is left 10-20 minutes it regains ALL its performance for the first couple of pulls.

[newsh]

So it is probably knocking and holding back, this is exactly what my old avant did until we put new rings in it.

[HMS-S6]

So it is probably knocking and holding back, this is exactly what my old avant did until we put new rings in it.

Yeh, possibly. I'm hoping that the place it's going to will be able to watch the knock sensors on his breakout box thingy.
Still strange how it's ok sometimes but I guess we'll see.
Be a prime excuse for asking JP to rebuild it into a monster!