mike13

iTrader: (27)

I attached the tune and idle log, idle surges up and down a little in park and neutral but when you but it in gear it really hunts up and down.

E85
127lb injectors
390
4000 stall 4L80
the wideband is ngk and only has the gas scale, that's why it looks like it has gas afr's.

Thank You

Chevy406

iTrader: (12)

* Start off by setting your idle ignition advance to mid 20s.
* Make sure your idle>in drive and idle>in park tables match and that they also match your high octane table up to 1,200 rpm or so. Needs to blend seamlessly from idle tables to high octane table. Your huge step from 19° to 30° between 800 and 1,200 rpm in the idle tables is probably causing most of the problem. Get those 19° tables up 6 or 7 degrees and blend into the high octane table.
* Idle Underspeed Spark vs RPM Error is too aggressive. Take out half or more in the -25 to -250 fields.
* Idle Overspeed Spark vs RPM Error is better but could be reduced a little from 50 to 200.
* Injector Flow Rate vs KPA VAC - set at 127 all the way across... Do you have a boost referenced fuel regulator?
* How comfortable are you with the injector flow data?
* I'm a little suprised to see you don't carry the PE table out past 3,600 rpm. Even with an enhanced OS boost table most folks set the PE table and use the boost table as a backup. The way I understand it is slower to react than the PE table.
*Base Running Airflow>Idle Airflow - I assume you have scanned and set this table appropriately?
* Primary VE - What's up with all the peaks and valleys? Lot's of room for improvement with some smoothing.

Maybe some of these comments will help with your idle surge. I typically work on smooth ignition idle tables and then look at idle airflow.

mike13

iTrader: (27)

chevy 406 thanks, yes boost referenced, smoothed the timing tables and is getting better, still needs work.

Slowhawk

iTrader: (12)

Boost reference is good but I do not use the vacuum reference. Have found it to affect idle too much.Can cause surging ect.

Chevy406

iTrader: (12)

That's interesting. I haven't really noticed a problem when the manifold reference reduces fuel pressure at vacuum, but it might be interesting to experiment with a check valve in the reference line.

mike13

iTrader: (27)

How do you run your reference line? Check valve? I've noticed since the switch to E85 that it seems to react different to the underspeed and overspeed timing. I ended up chasing my tail.

Slowhawk

iTrader: (12)

Reference it before the throttle body. The side port next to the cable works good.

Chevy406

iTrader: (12)

I have my HP Tuners usb stick with me today so I did some copy and paste to your tune in the VE, timing and idle areas. This might not exactly work for your particular setup, but it may help get you closer.

mike13

iTrader: (27)

thank you

mike13

iTrader: (27)

I appreciate it.

MMWS6

Slow, you may have just helped me with something that has been kicking my ***..... thanks for the input man, Im going to give this a try for sure