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

[Scott Simmons]

The injectors fire two at a time?  So it fires both 1 and 6?   Because 
either 1 is firing at TDC or 6 is firing?

That being said, how does it time the spark?  Do both 1 and 6 spark?  
The pin will only tell when 1 is at TDC, so it's either TDC for 
compression and 1 is firing, or it's at TDC for exhaust and 6 is firing.

I know on the 944s I worked on, all 4 injectors fired at the same time, 
so the computer only had to know where TDC was.  The coil would energize 
twice a revolution and the cap/rotor would get it to the right cylinder.

But the V8q has two coils, so how does the computer know which coil to 
fire?  Or does it fire both coils and one just ends up being wasted?

~Scott S.

Tony and Lillie wrote:

> They fire two at a time. That is what the hall sender is used for. The 
> computer uses the hall sender to determine #1 TDC. Which is one of the 
> reasons for the slight hesitation if the hall sender is unplugged.
>
> As fro wasted spard, you are thinking of a COP setup. With a 
> distributor, you can only fire each cylinder once per revolution. The 
> width of the rotor is what gives teh ECU adjustability. But, only a 
> certain amount. Basically, if the coil fires, the spark is going to 
> the cylinder that the rotor is pointed at. And, each coil fires four 
> times per engine revolution.
>
> Tony Hoffman
>
>
> ----- Original Message ----- From: "Scott Simmons" <indischrot at gmail.com>
> To: "urq" <urq at pacbell.net>
> Cc: <v8 at audifans.com>
> Sent: Tuesday, March 18, 2008 8:56 PM
> Subject: Re: [V8] sanity check, what, from a V8Q owner?
>
>
>> Are we saying that the V8 uses wasted spark?  Also, what times the
>> injectors?  I assume they're batch fire.  Which fire at what time?
>>
>> ~Scott S.
>>
>> urq wrote:
>>
>>> For an engine with a distributor and an even number of cylinders it 
>>> doesn't
>>> matter whether you're at TDC compression or exhaust, the time to 
>>> fire the
>>> coil(s) is the same.  My V8 ran for a long time with a no Hall 
>>> Sender signal
>>> code.  Odd number of cylinders, or coil per plug then the ECU needs 
>>> to know
>>> whether it is exhaust or compression.  An I-5 will not start if the 
>>> Hall
>>> Sender is bad ... the PT in a V8Q will ...
>>>
>>> Steve B
>>> San Jose, CA (USA)
>>>
>>> -----Original Message-----
>>>
>>>
>>> so who does if not the Hall sensor? ;)
>>>
>>> 73
>>>
>>> Bastian
>>>
>>>
>>> Scott Simmons schrieb:
>>>
>>>
>>>> The ignition sensor pin the flywheel will only tell you if you're at
>>>> TDC, but not if it's compression or exhaust, BTW.
>>>>
>>>>
>>>>
>>>
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>>
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>
>