Engine Stopped

You change it once a time... so you should know, that a new one looks that way... it's fully normal

Grateful to both of u, Martin and Roy. Last time i didn't see the replced cap as it was replced by Audi workshop. I only saw the removed one.I was about to buy a new one but u saved me from this.I also removed spark plugs and checked the wires and found all good.As i mentioned before that i checked idle stabilisation valve, Throttle position sensor and air flow meter and found all good. My G4 also good as its reading is 0.99 ohm but reading of G28 is 0.96 ohm which should be similar as G4.what do u suggest should i replace G28 sensor (engine speed sensor)? Next quiry would be how to change. I tried and loosened the upper bolt of shield but no space of tool for lower bolt as the exhust pipe is very close. kindly guide.Many thanks.

Try to start the engine, don't turn ignition off... then read out the engine fault-codes

LINK

Then you should know what is to do...

The code i pulled was 2111. Now i can not remove the lower bolt of shield covering the sensors. upper one i could remove but there is no space for conventional tool between shield and exhaust pipe. i am thinking bout grinding one of 10 hexa key so that it may fit with ratchet in the narrow space.For a common problem, it should ve been easily accessible. any hint?

I changed the G28, RPM sensor but not starting yet. I checked for spark which was present in all 8 cylinders.i think fuel pump not pushing gas. i checked the noise from pump while switching on the ignition. no noise was there. when i checked for electric continuity through pump, it was ok.i think ECU not giving current to fuel pump. i pulled the code it z still 2111 despite i put new sensor. may be ?bad electric connection of G28 with ECU.this may be the reason.where is ECU located and how to check.i ve no VAG 1551 but know how to blink the codes. i need help and guidance. Thanks a lot.

This fault code you have when the engine didn't run.
Fuel pump, I think - I'm not sure, only runs when you crank or run the engine. Only turn ignition on didn't switch the pump on (for some seconds) like on other cars.

Check the voltage to the injectors. You have on one side the 12V switched via relais (I remember that the V8 has 2 relais?) and on the other ground which is switched by the ECU.
When you have some sparks I thin think the ECU control ground (PWM signal) is ok and you will have some problems with the 12V voltage.

Now i removed return pipe of fuel and there was no sign of fuel while cranking. I think the pump electric circuit is OK but mechanically it z not working.If there is problem with injectors or voltage of injectors then fuel should come from return pipe. code 2111 is false when engine is not running. Audi repair manual guides how to check the fuel pump and uses a remote control at fuse 17.what is an alternate way of checking the pump without removing it?

Driving the car is other option

You could get direct the voltage on the connectors of the pump.
Sometimes the pump is only blocked, 2-3 times with the voltages and the pumps works for some days.

I'm using a lot of concepts/ideas from working on my Ur, as the basic ideas are the same. (it's just the number of cylinders that's different)
So please, correct me if I'm wrong in any of this-

The fuel pump I expect to be controlled through the ECU. If the ECU is not getting a signal that the engine is running, the fuel pump will not be activated.

The ECU knows the engine is running from the sensors on the flywheel. One sensor provides tooth count from the flywheel. The other sensor provides a trigger point for the count, using a timing pin on the flywheel.
In ur circles in the UK, there have been a number of occasions when the 'timing pin' has been damaged, either from poor starter motor replacement methods. In some cases, the pins have seemingly 'fallen out'. It does not matter. No pin= no timing trigger= no start. It's the same effect as having a bad sensor.
The tooth count can actually work quite well, even with several teeth damaged, so long as the timing pin is present.
The fuel system will normally maintain a fairly good level of fuel pressure. I did think that the pump was briefly run when the ignition is turned on. A common trait of poor fuel pressure in the system extended cranking before it starts.

A test of the fuel system would simply be done by supplying 12v directly to the pump, bypassing all the controls. This is probably what is refered to by Fuse 17/remote control.
The alternative is access to the fuel pump electrical connections which are under a circular plate in the boot(trunk, for colonials). This access plate is under the black carpet, on the ridge immediately behind the rear seat. About where the 'ski hatch' is. The plate is held in with screws. So you need to pull up the piece of carpet that is stuck down. The connections for the fuel level are also there.
If the fuel pipes are disconnected at the engine, then this is a good time to check not just that the pump runs, but also delivers enough fuel. So put the pipes into a petrol container, and run the pump. If the pump runs, then check delivery. Pumps always deliver significantly more fuel than is required. A good pump in a k-jet injection system delivers in excess of 900ml in 30 seconds, if I remember correctly. I would use this as a benchmark unless anyone knows of any other figure.

If the fuel pump was making any noise (loud buzzing, etc,), then fuel pump failure could be a possibility.

As I said- all of this is open to correction.

Hi,

everything you've said is 100% true from what I know. The behavior regarding the pin and the flywheel sensors is identical at the V8. The main difference between the Fivebanger and the V8 is that the V8 is able to start also without a working Hall sensor, whereas the Hall sensor is required on Fivebangers.

Best regards

Bastian