Timing During Start

[HAILERS]

With the key to ON and engine OFF the Palm shows -25 degrees for lead and trail. The question is, is this figure a default number that represents nothing? I assume it is since the FSM says timing during start is 5 BTDC. During the actual cranking the figure never changes from 25, only after start does the figure change. Come to think of it I never have tried to log a start before and maybe it would show in a log? Just thought of that, but would like an answer about the number -25.

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[danec020]

I was actually wondering this myself.. Any word back? I don't know if you remember Hailers but we were talking about the timing awhile back when I thought I had an issue. Anyone have an answer to this question?

Thanks
Dane

[turbo2ltr]

The ECU sends over "raw" data, usually an 8 bit value (16 bit in the case of RPM, Airflow and injector PW). The raw value is then scaled to be human readable within the PDA. -25 is the result of a zero raw value. Henrik will have to confirm, but I will take a guess that if the motor isn't turning, the timing value isn't calculated in the ECU and defaults to a zero value. During start, a predefined timing value may be used, not in the map, so again the value is not updated until the ECU doesn't see the starter signal. But thats a guess.

[Henrik]

Mikes got it. Timing is not updated unless the CAS is spinning. I'll have to check if its fixed during start or not, its been a while since I was in that part of the code.

-Henrik

[HAILERS]

Here's the deal. If one disables the fuel pump and tries to start the car you can look at the PW and see what the PW is during start. Done that a number of times. Liked that feature of being able to do so.

Soooooo, one day I looked at PW and Lead timing and noticed the timing stayed -25 while cranking and only changed if the engine actually started. Soooooooo I fooled myself into thinking the timing during Start was -25. Bad thinking since the FSM says it's set at 5ATDC (I think).

So, I became and probably am still confused about what the timing is during the start cycle. Right now I'm fairly sure the timing isn't shown at all during START, only if the engine actually starts, unlike the PW which is shown during start.