[V8] sanity check, what, from a V8Q owner?

[Scott Simmons]

The ignition sensor pin the flywheel will only tell you if you're at 
TDC, but not if it's compression or exhaust, BTW.

~Scott S

Bastian Preindl wrote:

>Hi,
>
>I also own the self studying plans of the Audi V8Q which detail the Hall 
>sensor and ECU behaviour in cause of fault. The BTDC is reduced afair, 
>that's it and the ignition point sensor values are used as substitution. 
>Nevertheless we've spectated that for some reasons a defect Hall sensor 
>causes the engine not to start - believe it or not.
>By the way: Also the V8 needs to know if you are at TDC on #1 - that's 
>what the ignition point sensor measures. The Hall sensor is only needed 
>to correct differences caused by lengthened or not perfectly calibrated 
>timing belts and when being up in high UPMs. For all other situations 
>the TDC on #1 could be easily calculated by knowing the ignition point 
>sensor value. The situation is similar on the I5.
>
>Regards
>
>Bastian
>
>cobram at juno.com schrieb:
>  
>
>>I think the only difference would be whether the Audi is a V8Q or not. 
>>Because of the even number of cyls and the distributors firing at fixed
>>degrees, the ECU in this case does NOT need to know (unlike an I5) if you
>>are at TDC on  #1 or not to run.  It does effect the knock sensor  (which
>>default to 16 deg. BTDC) making for less than optimal performance, but
>>not related to starting at all.
>> 
>>The hall signal is used with other parameters to time injector firing to
>>reduce emissions, aside from this it's like a CIS system in that it
>>doesn't matter for normal operation.
>>
>>Former lister Keith had a very good write up on it take from the Audi
>>literature, it's probably in the archives somewhere.  
>>
>>Easy to prove, disconnect the hall sender @ the distributor on any V8Q
>>which doesn't have a preexisting problem and see for yourself.  
>>
>>  
>>    
>>
>
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