Thread: Idle timing table VS Main timing table....Dave or John?

Ok, hope i got it now.

So when the correlation between the two match, then there is ZERO degrees added to the main timing map.

and when there is a difference in correlation between the two, then the difference is added/subtracted from the main timing table?

All correct except that last part. It is added/subtracted from EVERYTHING having to do with timing. Not just the main timing table.


Imagine the ECU sends out a timing value. Whatever that is. It sends it to a black box which adds (or subtracts) something to it. No matter what. And that's the timing you get.

if bens explanaition isnt clear...

how the ecu and the engine calibrates timing values is through the idle table.
if the table states it to be 15* then the mechanical timing that is confirmed using your timing light should be 15*

by advancing your mechanical timing (bumping your distro) to say 19* degrees, you would have added 4* degrees to every timing adjustment the ecu would communicate to the engine.

hope that helps

thats how i've always understood the dist timing to work. what you advance over the stock value of 15 you add/subtract to all timing values BUT if i try this 25deg of distributor timing at idle how is it not adding 10deg to all timing values then?

Is this because my 25deg of distributor timing would match the 25deg timing in the idle table?

Do you guys up the idle timing on big cam engines or just leave stock?

Thanks for all the help guys

the table is used when the TPS is in the closed state (ie Idling)

when the TPS is open the 16x16 timing maps are used....

John said that earlier... post #2

because you synchronized the computers timing value with the mechanical timing on the distributor...

by setting the mechanical timing to 25* doesnt mean the ecu cant/wont be able to have the distributor fire at 10* before the piston hits top dead center...

So when the mech timing matches the timing in the "idle timing table" then there is ZERO addition/subtraction to the rest of the timing tables.

When there is a difference between the two tables, then thats when u will see an addition/subraction to the rest of the timing tables.

I was in the same boat as you Hualin200sx.

After my Tomie 256/256 11.5mm Lift PonCam install my car likes to idle smooth around 950rpm at 20deg timing.

My tuner has set the idle at 20deg at the CAS/Distro and on the Standalone ECU (HKS Vpro) also at 20deg this is for the IDLE MAP. They both match! Thus no Offset.

As for the timing map the Standalone ECU (HKS Vpro) has full control of whatever the tuner wants it to do. Again NO +/- (offset) Not based on whatever the idle timing is set at.

**If your ECU is stock and you mess with the CAS/Distro say advance +/- 5 deg then yes it will advance/retard the whole map, because its STOCK ecu which is based at 15 deg.

Hope that helps.

Steve.

I do believe you're right Haulin200sx, but Dave or John will have to confirm.

I don't know if Tunercode has the same "ignition timing set mode" that the stock ECUs have. This removes all timing trims and locks to some known timing. (I guess it used the idle timing table?)

OK, there is a lot of stuff in here that is definitely confusing.

Let's simplify this a bit.

The "IDLE TIMING" table is ONLY USED when the throttled is closed and the car is at an IDLE .. this has NO CORRELATION to the "MAIN TIMING" table. They are two separate tables and are used independent of each other.

If you add 5 degrees to every value in the "IDLE TIMING" table it will ONLY affect those values .. it DOES NOT add 5 degrees to the "MAIN TIMING" table.

So to do this properly, you would do as follows.

1) Set your "IDLE TIMING" table values in NismoTronic to 20 degrees.
2) Check the Timing Mode option to lock the timing value from any corrections .. you can view the "FINAL IGNITION VALUE" in the data screen to confirm the timing that the ECU is currently requesting.
3) SYNC your mechanical timing to the value that you are seeing in the "FINAL IGNITION VALUE" log item on the data screen .. if you set it to 20 in the first step, then you should see 20 as the final ignition value and then should set your distributor to 20* at the crank pulley.
4) UN-Check the timing mode check box

NOW .. All of the values in the "IDLE TIMING TABLE" and "MAIN TABLE" should now match what the engine is actually seeing.

For example, if you put 24 in the "IDLE" table then you should see 24* at the crank pulley with a timing light (without adjusting the distributor!)

Moral of the story is sync the ignition at idle with whatever you are seeing as your final ignition value with the "Set Timing/Idle Mode" ON. Then all of the values in ALL of the tables will match.. so you can adjust the IDLE timing INDEPENDENT of the main table.. if you are just trying to smooth out your idle.