A drowning V8 with a G40 error (motronic problem) - www.AudiV8.com

Help!!! After 2 months of searching I can still not find the error in my dear V8s engine steering system (motronic). I had even been pushed so hard, that I tried to send the car to an authorized Audi dealer for repair. And for me it is a big time humiliation, to admit that there is a problem I can’t crack, but never the les – this is the case.

BUT!! I just got the car back from the Audi dealer. In Denmark Audi take €120 an hour, and this is plain robbery in broad daylight. At the same time they didn’t find anything the first 8 hours they used, so I stopped the gambling and took the car home again. The problem is also that there is only aprox. 13 Audi V8 PT 3.6 registered in Denmark, so they have absolute no experience.

Well.. let me describe the problem.. The car can be started, and the engine can run at idle speed, but not smoothly. If you touch the speeder to hard, the injectors send a shower of gasoline in, and the engine drowns. To start again you kneed to empty and ventilate the engine for excess gasoline – it is really drowned big time.

And what have I done – well – I have diagnostic equipment (a palm based system, that equals VAG 1551), and it tells me that there is no signal from the HAL sensor G40. (Hal geber). I have tested the hal unit numerous times, exchanged it with a unit from my spare V8 car, and finally exchanged it with a brand new unit.

All wiring has been tested 10 times (The 3 wires going to the ECM (motoronic computer unit) 1 to 12, 2 to 8 end 3 to 19.) The voltages going from ECM to Hal has been tested. 5.2 V between 1 and 3 and 4.9 V between 2 and 3. And the output signal between 1 and 2 was tested with a diode signal tester. Finally the ECM was exchanged with the one from my spare V8.

But still I got the G40 error. Then I tried to “blink” out the errors codes the old fashioned way and got code 2113 witch equals G40. To be absolutely sure I tried a real VAG 1551 and still got G40.

The really strange thing is that the symptom from the engine does not fit to a G40 error. This error should give bad performance, but not at fatal drowning. So I decided that the G40 error must have been a ghost from something else.

The diagnostic system shows NO other errors than G40.

Now I have exchanged EVERYTHING relevant (E.g. relays, fuses, ignition parts, gasoline pressure regulator, new gasoline filter, gasoline pump, air mass meter, idle valve, throttle position senor unit, RPM sensor, crankshaft position sensor, oxygen sensor (lambda) etc. etc) with the corresponding part from my spare V8. (Remark – my spare V8 was driving perfect when I took it home from Germany some months ago.)

The oxygen sensor is almost new - 5000 km and show no errors. Despite that I’m almost 95 % sure that both my air mass meters are OK, I exchanged with a new one – cost a fortune, but the f..!#%"¤%"#¤%"# car can still not drive.

So now I ask thy – without greater hope. Do anybody here ever tried a similar odyssey, and does anybody have a good suggestion? My next step will be to exchange the entire engine wiring assembly.

If this also is without result, I burn the car and buy a French car – they are at least supposed to do this kind of things. To look at a non functioning Audi V8 for 3 months, is like being buried alive.

You are welcome to answer in German. I can read and understand this, but I only speak and write english.

With regards

Lars

Lars Bak

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