Our base timing is usually set at 6 degrees BTC right? What is the wire that you have to disconnect to set this? How does the computer work, does it start at the base timing and use it's programming to adjust from there, or does it just change how it feels necessary? What I mean is, will adding base timing be beneficial, or will the computer just pull timing to compensate and give me the same overall timing anyways (assuming there's no more knock then at a base of 6 degrees)? Thanks.

 

The spark tables in the ECM are fixed, unlike the fueling. It will pull timing out only if there is knock present, otherwise you will get whatever you add with the base timing.

The wire is on the passenger side of the car under the hood, brown/tan wire with a black stripe. Has a single weatherpack connector just above the AC box.

 

LIke madmax said...

Initial Timing + ECM controlled Timing = Total Timing.

So Bumping the Intial timing 2 deg will effectivly increase your timing 2* acrost the range, Providing there is no Resulting knock.

 

Why do you disconnect the brown and white wire?

 

The ECM adds timing, even at idle. So, if you set the base timing with it connected, it would be around 10-15 degrees retarded. Not a good thing.

 

Cool, that's exactly the info I was looking for. Thanks a lot.

 

What you should also know is that it's best to mess with the timing under controlled conditions so you can actually tell if you're accomplishing anything. It's really easy to bump the timing a couple degrees and have it feel faster off the bottom, only to have it actually slow down because it gets into detonation in the midrange and has the knock sensor take all the timing out.

You want to play with your timing under one of the following conditions:
1- at the track or witha g-tech. Obviously here you can do plenty of back to back testing to see what works the best
2 - with a scan tool. At least with a scan tool you can see if you're getting into knock
3- with the knock sensor bypassed. This way at least you can hear the detonation and know to pull some timing back out.

 

Thanks for the advice. I have access to a Snap-On Scan tool so I was planning on using that to look for knock on the top end. If I come across a good deal on a G-tech I may pick that up.