I'm Trying to get my car to start better. And to get it to Run correctly Right after start up. When i come to a stop for about 10 seconds or so the Idle Drops. This was due to a Timing shift of the engine not a throttle adjustment. The Stock system that controls timing vs Vacuum is Lame imo for a few reasons But i dont like it. . What is telling the ECU to change my timing when i am Under load or coming to a stop? And I notice that even if i have my Timing RIGHT on the money Sometimes when i start the car the Timing marks are off because i think the Computer is Firing the engine at some other timing point that makes the car Backfire Sometimes. And it wont start Right up. Would anyone know how i can adjust this? Vacuum controls the timing, But isnt there some Over ride or adjustment?

 

No one at all? No one knows how to COntrol Idle timing and Vacuum timing?

 

Could your bac valve be bad? That is what bumps up your idle under electrical load.

rotary>pistons

 

It could be.. Or i have a vac leak.. I sorta want to know what triggers the timing to change under load.. I need to find that part

 

The timing map is burned in to the ECU. It's essentially an excel spreadsheet that has %load(vacuum/pressure) on the y axis, and rpm on the x axis.

If you're setting the timing correctly, then you'd know to jumper the initial set coupler, and that the idle speed has to be <1000 rpm. That will lock in the base timing signal so you can adjust it without the ECU continually adjusting the timing.

The timing shift is a RESULT of the idle speed drop. It's probably advancing the timing a little to accommodate for the drop in RPM.

Moral of the story: follow the FSM for setting timing. Fully warm up engine, adjust idle speed, jumper initial set coupler, set timing.

 

Ok thanks sir. I will look into it more. I gotta find that set coupler. I understand the ECU changes timing with Vacuum. But i know vac lines dont goto the Ecu. So what tells the ECU what vacuum it has. Is it the set coupler that tells the ecu?

 

Pressure sensor... Don't mess with it!

 

the set coupler is by the battery, the S4 is a 2 pin green connector you need to jumper, and the S5 is a single green pin you ground. the set coupler puts the ECU into a "fixed" map, so you can set the timing and idle speeds

the ECU actually has different zones or "maps", there is an idle zone, which is basically anything from 0-1098 rpm, in this zone the ECU will run -5L and -20T. above 1100rpm the (actually every ecu does this) ECU calculates timing (and fuel) by RPM vs LOAD. you are saying vacuum, and its the same idea, but the ECU primarily uses the Air Flow Meter as its load input. the FC also has a sensor for vacuum/pressure, but it isn't the primary one.

the pic is the zone chart, i think this is the FD one, but the FC uses something really similar.

 

From the last page of the electrical section of the FSM. Yes there is altered timing on deceleration.

If your TPS and throttle stop are not set correctly, it won't switch from 'decel' to 'idle' mode soon enough and the engine dies. Double check the TPS setting.

There is a different 'start' timing map used for about 10 seconds after startup. So don't use that to set your timing.

It sounds like you either have a big draw causing the alternator or AC to introduce too much drag on the crank or your timing is just set wrong.

Edit: And I thought my picture was going to be too big.

 

Awsome diagram j9fd3s,, and rxspeed. . I always wanted to find that page..