e38 ECU information

[swingtan]

Post the tune.....

[snax]

c6_z06_0007.tun

Here you go

[RAZRS EDGE]

Todays lesson is...returning engine to idle!!!

The car wants to die when you shift into neutral coming up to a stop light. You can see it best in the following datalog at around frame 455. Alot of the time the revs will hang around 1600-1700rpm for an excessive amount of time before it returns to idle speed, ~850ish. You can see the revs hanging up at around frame 420.

What tables should I be looking at for the idle issues?

Attachment 8876

Thanks,
Bryan

Post the tune.....

c6_z06_0007.tun

Here you go

Any thoughts? Thank you for everyones help!

[joecar]

Hi RAZRS EDGE welcome to the forum

What vehicle/year/model do you have...?

[swingtan]

OK....

1. Idle fuel mixture is very rich, way richer than commanded. You need to adjust the MAF to fix this up. Running very rich at idle will make it more difficult to control the idle.
2. Min idle air flow is very high, much higher that what the car seems to want. In the tune, you have around 12gm/S to 13gm/S but the engine is only using around 7 to 8. Looking at the log from frame 1092, you can see the ECM is slowly pulling air out to get the engine to idle at the required RPM. When you command too much idle air, the ECM needs to pull progressively more air and timing to drop the RPM to the commanded level. This then moves the ECM further into the "Idle Proportional Step Size" table, causing even more air to be pulled. The results tend to be massive over shoot of the idle control.

So this is what I'd do...

• Reduce the MAF table in the 1600hz to 2000hz range by 6% to 8% and then blend it back in. This should help with the fueling.
• Drop the "Min Idle Air" to around 8gm/S to allow the ECM to use less of the idle correction tables.
• Raise the idle spark table to 20' to help with idles control.
• Clean up the idle over / under speed control spark tables to help with idle control.
• Raise the minimum values in the idle and deceleration spark tables to stop the commanded spark from dropping below 10'. This will also reduce the amount of exhaust backfire ( crackle and pop ) when slowing down.

There is probably a bit more but this should be a start. Here's a tune that I've played with a bit.....

c6_z06_0007 (1)_0000.tun

I can't say if it'llmake things better or worse though.....

[RAZRS EDGE]

Hi RAZRS EDGE welcome to the forum

What vehicle/year/model do you have...?

Thank you for the welcome and help!

My personal car is a 2006 Corvette Z06.

[joecar]

Did swingtan's comments/edits help...?

[RAZRS EDGE]

Did swingtan's comments/edits help...?

Absolutely!

[joecar]

Cool

[BowlingSS]

How it is running now?

Bill