weird timing reading

[TEK310]

-21* at idle. whats wrong?

 

[MoarkatsINmuhtrailer]

What scanner are you using? Some scan tools read negative, for what ever reason I have no clue.

 

[matt5112]

its a 97.

it reads timing relative to TDC.

 

[tylerbinski]

its a 97.

it reads timing relative to TDC.

This ^

 

[MoarkatsINmuhtrailer]

its a 97.

it reads timing relative to TDC.

Ahh gotcha

 

[TEK310]

so that is normal? can you explain why it reads negative when reading relative to TDC?

 

[DanGTP]

If you think of your timing as a number line with TDC in the center, representing zero, and 180 degrees on either side, anything to the left would be negative, or before TDC. So 'timing' is negative in this case. In newer computers, 'timing advance' is calculated and displayed as a positive number. However, it still represents the same value. I hope this description makes sense to you guys... At least it makes sense in my head...

 

[TEK310]

thank you. that makes perfect sense, same as how timing advance was taught to me at school, think of it as you had a meeting at 12 and it got advanced to 10. they just never taught me to look at it as a negative number.

 

[darkhorizon]

its a 97.

it reads timing relative to TDC.

wrong.

3800 timing is measured in advance via the PCM. Base timing is 14 degrees.

97's just have a negative number.. pretend the negative sign isnt there.