This weekend 88tripleblack came up from Philadelphia to allow me to burn some chips for his car. During the tuning we check many items and got his car running much better.

I did however pick up on one thing that his car seemed to have that mine did not. During the starting of the car, my laptop (that is plugged into the cig. lighter) never went off like it does in my car. I tried to fix the problem in my car by running a seperate power cord and putting some pretty good capacitors in line. This made it work about 80% of the time instead of never.

I also noticed that his car's starter was much quicker at turning the engine over than mine. I went out and poked around at his battery and noticed his was 675 CA and mine was only 450CA. We took a ride out to my parents dealership and located the largest battery they had that would fit. Brought it home and installed it.

First startup was super fast and no loss of power to the laptop at the regular cig lighter (no cap.) I was thrilled! I then noticed that my stalling problem was fixed too. Here is what was happening.

When I would rev the engine up in park/neutral the engine would rev very quickly, but when coming back to idle would just stall. I am 99% sure this is why:

The ECM uses a table called battery correction voltage for fuel delivery. Since my batter was not working properly the car was primarily running off the alternator. Well the alternator is a function of RPM to some extent. So when I would rev up the car the ECM would see a different voltage being supplied, correct for it, then the car's RPM would slow and the ECM must not have been able to make adjustments fast enough and hence the engine would stall.

I always noticed that the voltage indicator inside the car would raise on revs, and lower quite a bit. Now with the new battery, it hold right at 13.8-13.9 Volts no matter what! No stalls could be invoked no matter how high I revved the engine or how little. The idle is a million times smoother too.

I guess I wanted to share this with you all in the event someone else is having similiar problems with stalling. I never realized the batter was that relavant to a smooth consistant idle.

Maybe I will pick up some performance too, but I think that would be a stretch.

Later :cheers:

 

:eek: Me neither!

Thanks for posting that discovery! :cheers:

 

War Machine....

What do you drive? A tank? :lol: :lol: Sorry I couldn't help myself..


[Modified by ski_dwn_it, 1:09 PM 6/24/2002]

 

Good to know. Thanks.

 

:lol: :lol:

I could mod the targa to pop up and expose a rocket launcher. ;)

 

The first thing to check when a computer controlled car is not performing right is the battery and charging system because as you stated it screws up the ECM> :yesnod: