Why is my timng at idle 13.500 degrees?

[Italian LX]

After my car has been running and reached operating temperature, my spark at idle holds a very steady advance of 13.500* which seems kind of low to me. It will bump up to around 15* every now and then, but usually returns back.

As I learn different aspects of EEC management, I've been trying to watch my datalogs and see if I can figure out exactly how the computer came up with certain values. This is one of the instances where I just can't figure it out.

I have looked at all the functions, scalars, and tables related to spark advance, but I can't find where any combination would pull my spark down that low. What am I missing here? :think:

I do know that the EEC will use spark retard to control idle if it can't do it using the IAC, but it doesn't appear that my idle is in bad shape. Also, wouldn't the spark actually be flucuating if it was being used to control engine idle speed?

[Sendero]

Brian, someone on the TwEECer board had the equations of how the EEC calculated final spark. Not that it would specifically answer your question, but I think it would be relevant for this discussion.

Clint, do you have any insight on this because I am coming up empty on the searches.

[Italian LX]

Brian, someone on the TwEECer board had the equations of how the EEC calculated final spark. Not that it would specifically answer your question, but I think it would be relevant for this discussion.

Clint, do you have any insight on this because I am coming up empty on the searches.
Yeah, I searched the TwEECer board last week for timing threads; came up with a bunch of interesting stuff, but I never could find an answer to my question.

I guess I need to post this thread over there. too. :huh:

[86GT]

If the EEC sees the idle as being to high it will reduce spark. If you are constantly above the desired idle the spark will go down as far as 15. Then if there is multipliers for ACT and ECT the spark could go lower. It seems as if the TB set screw is set to high. The EEC can not control the idle, so it tries the best it can by lowering the spark to its max.

I personally have not looked into the final calculation for the spark. I have not needed to. I just use the three spark tables in the tables section.

Keep in mind that FN901 is used under loads defined by FN125. Table FN904a and 905a are used if the load exceeds FN125. You then have to add all of the multipliers and adders.

[Italian LX]

If the EEC sees the idle as being to high it will reduce spark. If you are constantly above the desired idle the spark will go down as far as 15. Then if there is multipliers for ACT and ECT the spark could go lower. It seems as if the TB set screw is set to high. The EEC can not control the idle, so it tries the best it can by lowering the spark to its max.
Ahhh, that makes sense. I'll try resetting my idle and see how that does. :nice:

[Sendero]

Ahhh, that makes sense. I'll try resetting my idle and see how that does. :nice:


On that subject, what is the correct procedure on setting idle on a fox? Isn't there something like setting the TB screw, turning the A/C on and off, and etc?

[Italian LX]

On that subject, what is the correct procedure on setting idle on a fox? Isn't there something like setting the TB screw, turning the A/C on and off, and etc?
Look at the FAQ forum over on the TwEECer board.

[Sendero]

Look at the FAQ forum over on the TwEECer board.

Whoops, I meant to ask for a non-TwEEC'd car. Since we swapped the Cobra intake and full length headers onto Dad's car, he's having idling issues (cold start). I never did set the idle correctly and there is a manual way to do it, but I am not sure how.

[QWKSNKE]

you can do it with the t/b screw or you can follow the procedure that is in the EEC Analyzer software and use your tweecer off the cobra long enough to data log the IAC duty cycle while setting the idle