I had some time today to mess with my car. I have taken out alot of fuel in the 60-70kpa area for idle. THe pulse width is under 2.0ms(at idle fully warmed). The thing is starting to run really good. Most of the time starts on the first rotation. I did noticed that big cam want to have a higher idle when cold and warming up. thought it was stumblling when cold because of being rich. It just needed the cold idle bumped up.

I also found out why my p/w was doubled when in cold. I thought it was the open loop f/a ratio vs coolant temp causing the car to run way rich when cold. That table did little to decrease "cold" p/w. It was actually the "open loop change to f/a vs map" table. That's because my kpa @ idle is not in the 0'd areas in that table.

Everything is going great. I did noticed something that I cant explain. When the engine is warmed up and idling, the spark advance varies from 17*-25*. None of my tables are set lower than 20* . I attached a log file with the matching bin. Could someone explain what's going on?

 

Could be something similar to this

 

I just went thru a somewhat similiar issue. My new 4.2 is enough larger that I had to add some to the IAC hot start table for it to start up quickly.

Is there a table for spark timing correction based on idle RPM error?. That'd explain 3d.

Again, Source Code would offer the answer.

 

Keep in mind that if the throttle is closed then you are not using the normal SA tables. You are using the closed throttle SA table. This is one of the most forgotten things I have seen. In TunerCat it is called "Closed TPS Spark Advance vs. RPM". Don't forget to always add in the "Base Cool Advance Correction vs. Load vs. Coolant Temp".

Tim

 

Like I said, all my tables are 20* or above(I think). If someone wants to check out the log data and bin then let me know. I do know about those two s/a tables,BTW.


I thought you could attach zip files to post

 

The 730 8D has some Idle speed error tables that cause the
timing to jump up and down.

The tables are called: [in tunercat]
(Idle Spark Advance vs. Idle speed Error)
(Idle Spark Retard vs. Idle speed Error)

I think the tables are set at 4.9deg.

I played with them and the big cam needs 2deg in the advance
tables and I have the retard tables zero'd out.

My timing is now very stable at Idle, jumps 1 or 2 deg.

 

The 730 8D has some Idle speed error tables that cause the
timing to jump up and down.

The tables are called: [in tunercat]
(Idle Spark Advance vs. Idle speed Error)
(Idle Spark Retard vs. Idle speed Error)

Anyone know what this table might be called in tuner pro?

 

I think they are just for startup. Check out the rpm range. I always start logging data before I turn the key and start the engine. The scan data showed the ecm was showing knock retard at startup. My ks is disabled so that shouldn't happen. I didn't investigate because I get 0 retard when the engine is running. I guess one of those tables would have retarded the cranking s/a. The crazy thing is they seem to cancel out any adjustments in s/a because the amount of retard and advance (in both tables) are the same......

I guess my timing was reporting different s/a (at idle)because my car was loping and the rpms actually dropping for a spit second and the aldl didn't display it. I will raise the idle rpm to 800-850 and the timing should be solid.

 

11sORbust....

I have the same problem with my timing jumping about 5 degrees and this happens only at an idle and I have a stock
motor.. my closed throttle spark advance is set identical to the main spark table that correlates to idle rpm and map but it still jumps and whenever it does my motor gives a little shutter that make the idle not smooth... anyone have suggestions....