V6 quattro sedan is calling to me...

[gunman]

Maybe an evening would sort it if the car is in a well lit garage ?

erm, its on the driveway and I've big tripod mounted halogen light at it tonight lol. I suppose I could park the manta outside for an evening. I may well take you up on your offer as I'll be honest and say i'm a bit lost.

As you say it'll be a while before you could get looking at it so I'll try a few more of my mad ideas here to see if anything helps.

I'll be in touch.

cheers

mark

[S2central.net]

I've just looked up here and have all the factory data for the AAH engine - including fault codes and all the other fun and games on this relatively weird MPI system - but Audi being Audi will have lots of commonality with Bosch stuff from same era so I'm not too worried. Nothing can't be fixed...

[Flat on my back]

Remember...

ECU here...4AO 907 473B...

[gunman]

is that def the part no for the AAH? I was trying to buy one but needed the part number, havent got mine out yet?

[S2central.net]

The good book says that at least 9V should be observed across the supply rail of G40 on the V6 MPI engine - so forget the 5V assumptions.

With an LED tester you should see a pulse on pin 2 of G40 - wrt 0V earth - on every camshaft rotation... If not, then either G40 is dead or the camshaft aint turning !!!!

[S2central.net]

Careful with AAH ECUs - they changed in August 1992 - so MY92 and MY93 cars are different...

I wouldn't condemn the ECU until all wiring is checked and all sensors shown to be sane.

[S2central.net]

OK - been thru the relevant section on G40 tests and validated against the schematic... Added some thoughts of my own -

G40 pinout as follows -->

1 = red/black is +ve supply
2 = yellow/white is the signal wire
3 = brown/black for 0V earth

With the ignition ON and G40 connected up to the ECU as per norm - you should see the following results

Between pins 1 and 3 should be greater than 9V
Between pins 2 and 3 should be greater than 4V

To the last statement on pins 2 and 3 - I can only summise that the ECU must generate that voltage as a form of pull-up level - which I expect would be a nominal 5V.

If that 4V-5V signal is absent then the finger points at the ECU (or one of its fuses).

If you have the 4V-5V signal at pin 2 with the ignition ON but you never see pulses on cranking then the sensor is guilty.

Still dunno if 12V presence is correct on K & L pins...

[S2central.net]

OTher thing to check is that the POS unit has a good clean earth and that the connectors / loom into it are in good health... Failures such as that can cause a no spark condition.

[S2central.net]

If G40 and ECU looks OK, then I can dig further info out on G4 (crank ref) and G28 (rpm) sensors for the AAH engine...

[S2central.net]

Actually both G4 and G28 are easy to test - should see 1kohm across pins 1 & 2 in each case.

[S2central.net]

Finally for tonight - there are FOUR earth wires connecting to the ECU on its D-plug (16-pin Black connector) at pins 1-2-3 and 16.

Looks like pins 1-2-3 get earthed on the engine block on brown/red cables.

Pin 16 is earth via a brown/black cable elsewhere in the engine bay.

That lot will keep you busy until the cavalry needs to get called in !

[fzr phil]

may be silly, but you are using the same key?
incase the transponder in your other key does not work the ign immobiliser. i have the push in type immobiliser as well and there is one in the key. only time the engine cranked on mine without a spark was when i had key problems. (another long story!)

best of luck getting it sorted

Phil

[S2central.net]

I like your thinking there Phil - but this car is too old to have the fancy immo with transponders and the like... Unless someone retrofitted it !

I'll have a look at the factory immo wiring on the V6 from the bygone era of 1992.

[gunman]

Firstly, Paul, Thanks for all the advice on this, it is invaulauble.

The key for my car doesnt have a chip. it is the flat black plastic handled key, either way I've been using the same one. What is the push in type immobiser?

[S2central.net]

Just checked and there isn't any funky factory immo on a 92 V6...