The Outcome (Part 2) of "Audi just shuts off no warning while driving and won't restart"

[Huw Powell]

On 8/18/2011 11:58 PM, Marc Boucher wrote:
> I'll be definitely going at it now with a volt-ohm meter to try and get
> it back to match the schematics.
>
> If you had to guess, were they trying to establish ground from the hall
> sender, and they meant to connect the "green-white" cable depicted as
> "0" on the schematics to the engine block, rather than the brown-white
> labelled "-" ?

If I had to "guess" I'd say they were hacking it in a very clumsy, not 
understanding electronics way, to get the car off their lot.

I once left a local shop in my '83 5kt with the lights not even working 
right.  Bought a manual and found the problem and fixed it myself (some 
ign on component had melted a few wires, they hacked them, I fixed them 
over a weekend).

> The schematic shows that the IGN booster has a brown-white cable which
> is connected directly to ground. If they suspected a ground problem
> involving the IGN booster, why not ground the IGN booster, not the hall
> sender?
>
> I realize that this is beside the point, since the main point is to get
> it back to match the schematics. But I thought it would be useful to try
> and understand what they did and why they did it, since it DID solve the
> problem of the car not running.
>
> Thanks again,
> MC
>
> --------------------------------------------------
> From: "Huw Powell" <audi at humanspeakers.com>
> Sent: Wednesday, August 17, 2011 10:34 PM
> To: "Marc Boucher" <mboucher70 at hotmail.com>
> Cc: <quattro at audifans.com>
> Subject: Re: The Outcome (Part 2) of "Audi just shuts off no warning
> while driving and won't restart"
>
>
>>>
>>> Looked around to see what exactly they did to solve the "ECU ground"
>>> problem. *It appears that they cut the brown and white wire wire coming
>>> from the Hall Generator, and bolted it to the engine block in order to
>>> act as a ground. The schematics show that wire should go directly to pin
>>> 10 on the ICU.*
>>
>> Nice work. Striped brown wires are *switched* grounds.
>>
>>> **
>>> Their invoice says that they "Check wiring from ignition distributor
>>> coil and ignition ECU, Determine ground signal wire from ECU not
>>> functioning, Repair ground wire". According to the schematics, red-black
>>> wire is "+", the Brown-White is "-" and the "green-white" is "0". Does
>>> that make sense, to connect the brown-white wire to the engine block for
>>> ground? If not, could that have defeated the ISV ?
>>> MC
>>
>> If it made sense, it would have come that way from the factory. It
>> might be time to dig out or buy a VOM and do some checks yourself.
>>
>
>
>
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