URS6 Way Too weak!!!

[TimE-J]

At least its sorted now! Happy motoring.

[HMS-S6]

At least its sorted now! Happy motoring.

Thank-you. Best part is, its sorn and in the middle of a plate change

[prj]

This problem would be visible in VAG-COM though...
You know, if you run proper diagnostics with measuring blocks

Glad it's fixed.

[macspring]

Glad it’s fixed.

You’ll enjoy it once you are free to drive it whenever you want.

Good to know the cause.

[HMS-S6]

Well! Looks like i cures a newer fault than the long standing intermittent surging!!! Took it for a run today and t was Crap! But, just as it used to be, if i start it, unplug the crank position sensor it pulls way way better!!! Any ideas? Does this knock out the knock control???

[UrS4boy]

...Took it for a run today and t was Crap! But, just as it used to be, if i start it, unplug the crank position sensor it pulls way way better!!! Any ideas? Does this knock out the knock control???

The G4 crank position sensor is one of the three sensors needed to start the AAN (and ABY and ADU) along with the G40 cam position sensor and G28 engine speed sensor. Once started, the G4 can fail (or be unplugged) and the ECU will continue to figure things out based on calculations it was making when the engine first started. On that basis, you might have an actual G4 sensor issue, e.g. tip clogged with debris or a wiring issue. Worth a check by pulling and inspecting the G4 and G28 twins. More info here:

http://forums.quattroworld.com/s4s6/msgs/20986.phtml

[HMS-S6]

The G4 crank position sensor is one of the three sensors needed to start the AAN (and ABY and ADU) along with the G40 cam position sensor and G28 engine speed sensor. Once started, the G4 can fail (or be unplugged) and the ECU will continue to figure things out based on calculations it was making when the engine first started. On that basis, you might have an actual G4 sensor issue, e.g. tip clogged with debris or a wiring issue. Worth a check by pulling and inspecting the G4 and G28 twins. More info here:

http://forums.quattroworld.com/s4s6/msgs/20986.phtml

The two sensors are new and pulled them today and are still clean, i will check the wiring to them tomorrow as today i just ran out of my own time again! The horrible thought of it being something on the flywheel its self has crossed my mind too!!! Is this possible?
Its as if the signal from this sensor is incorrect (too advanced)

[UrS4boy]

The two sensors are new and pulled them today and are still clean, i will check the wiring to them tomorrow as today i just ran out of my own time again! The horrible thought of it being something on the flywheel its self has crossed my mind too!!! Is this possible? Its as if the signal from this sensor is incorrect (too advanced)

It is more likely that there is an annoying wiring problem than an issue with the G4 crank position pin. That said, to give you piece of mind (maybe), you might want to remove the starter and rotate the engine (on a hoist, trans in 4th and move the front wheel) to inspect the condition of the G4 crank position pin.

More G4 crank position pin position, or lack or therein, here:

http://forums.quattroworld.com/s4s6/msgs/51259.phtml

[HMS-S6]

It is more likely that there is an annoying wiring problem than an issue with the G4 crank position pin. That said, to give you piece of mind (maybe), you might want to remove the starter and rotate the engine (on a hoist, trans in 4th and move the front wheel) to inspect the condition of the G4 crank position pin.

More G4 crank position pin position, or lack or therein, here:

http://forums.quattroworld.com/s4s6/msgs/51259.phtml

Replaced the ECU with the cars original yesterday and went for a run. Can is now totally stamdard with a tank of super plus! Fuel pump wiring has now had the mod, had 13.9 volts at the pump and correct fuel pressure everytime. The temp reading according to vag-com is now between 94 and 97 when hot now. Air temp is also correct.

However coming off an island today next to an armco reservation, just as the car came on boost so to speak (around 3k) I could actually hear the thing pinking like a bitch just before it hung back untill around 4k (which its doing everytime its warm now)

Just went to data log and the thing pulled perfectly though

Any ideas what could make it pink with correct fuel pressure etc? My gut feeling is that something is causing week running but am clueless now as to what!!

[UrS4boy]

Pre-detonation (pinging or pinking) under those circumstances suggests lean conditions and/or a timing issue. You say you have perfect fuel pressure but when/how are you measuring it? With a 4 Bar FPR, you should have 4 Bar (58 psi) plus boost pressure at ALL times, e.g. at 22 psi (1.52 Bar) boost, the fuel rail needs to have 5.52 Bar (80 psig). Otherwise, the injectors will be supplying less fuel than the ECU expects them to do and pinging will occur until the ECU gets the feed back from the G61 and G66 knock sensors.

If your fuel pump is good and the fuel lines are somehow kinked, you might have a FPR problem. Click on the FPR label in the upper middle of this diagram (all the other labels are live links as well):

http://members.shaw.ca/speedtek/UrS%20Engine%20Bay%20Device%20Map.html

[newsh]

My avant used to hold back after a full throttle run through the gears and then lifting off the throttle then back on it again, the bores were glazed so I guess as I came off the throttle it would suck in some oil which would cause it to ping. Hone and new rings cured it.

[newsh]

The other thing to look for is a leak on the vac line to the FPR and a blocked fuel filter but I guess you've already been there.

[HMS-S6]

Pre-detonation (pinging or pinking) under those circumstances suggests lean conditions and/or a timing issue. You say you have perfect fuel pressure but when/how are you measuring it? With a 4 Bar FPR, you should have 4 Bar (58 psi) plus boost pressure at ALL times, e.g. at 22 psi (1.52 Bar) boost, the fuel rail needs to have 5.52 Bar (80 psig). Otherwise, the injectors will be supplying less fuel than the ECU expects them to do and pinging will occur until the ECU gets the feed back from the G61 and G66 knock sensors.

If your fuel pump is good and the fuel lines are somehow kinked, you might have a FPR problem. Click on the FPR label in the upper middle of this diagram (all the other labels are live links as well):

http://members.shaw.ca/speedtek/UrS%...ice%20Map.html

I checked it by fitting my gauge in the feed pipe to the injector rail. It has a faultless 4bar plus boost everytime! This is why its driving me mad, by all tests it should be running perfect

Even though i'm wanting to cure it myself, i'm at the point where i'd farm the job out if only i could find someone to do it?

[twoqu]

What about the injectors themselves. Certaintly a faulty injector might explain an intermitant weak condition but not explain why it runs better when the crank sensor signal is removed!
You will have to look at the subsitute function for crank signal. Seem to recall it goes to some default and ignores the knock sensors. Of course that might all be related.

[twoqu]

Looks like there is no substitute fuction for the G4. It's only used for starting and not needed for engine operation. Althought that doesen't explain what happens to your vehicle when you unplug it! Its the hall sender that ignores the knock sensor.