About to throw in the towel nailing down idle

[5_Liter_Eater]

The rule of thumb (IMO) is about 25 degrees. You don't want to optimize spark at idle. You want it middle of the road so the adaptive idle spark is able to quickly increase spark to speed up idle and quickly decrease spark to lower it.

[mdmbkr]

Right now I'm running around 12 degrees ... so you're saying reduce the airflow and increase the timing?

Another issue I have is that the VE table cell for idle is also used in cruise, so I can either be rich at idle or lean during cruise... or can that be fixed somehow?

[5_Liter_Eater]

Right now I'm running around 12 degrees ... so you're saying reduce the airflow and increase the timing?

Another issue I have is that the VE table cell for idle is also used in cruise, so I can either be rich at idle or lean during cruise... or can that be fixed somehow?

Just leave your timing where it's at and run through the procedure.

Your second question doesnt make sense and doesnt have anything to do with this thread. Start a new thread for that please.

[mdmbkr]

My second question does indeed make sense and is in fact relevant to the subject of idle tuning.

I have tuned my VE table to be accurate while driving. However, the same four spots in the VE table that are referenced during idle (800 rpm, 60 kpa; 800 rpm, 66kpa; 1200 rpm, 60kpa; 1200 rpm, 66kpa) are also often referenced during driving (primarily in 6th gear where I would be hoping to save gas). When driving the AFR is accurate. When idling it is about 8% rich.

I hope this clarifies what I was trying to ask earlier. Perhaps it indicates that my idle needs a lot of work?

[5_Liter_Eater]

VE is VE, it doesn't matter what mode you're in. 1200 RPM and 60kPa should be the same value no matter what condition. But again, this thread deals with dialing in the final aifrlow minimum table to get rid of problems like dipping or hanging idle. It has nothing to do with VE or MAF values or AFR.

[mdmbkr]

Sorry for stepping on your toes. I was assuming that AFR at idle was relevant to tuning idle. More specifically that the AFR error at idle as compared to while driving indicates that the actual VE of the engine at idle is being hurt by poor timing or airflow. This I think supports your recommendation to advance idle timing well beyond stock.

[mdmbkr]

Have you ever gotten "reduced performance" mode when tuning idle? The guidance is to command lower and lower RPMs to determine airflow but if I command much below 900 it wants to fall into "reduced performance".

Notwithstanding that .. I logged delivered engine torque vs timing advance, 400 counts at each degree, to determine max torque, which was at around 22 degrees. I subtracted 5 from that, setting my idle advance to 17 degrees, which is 4 degrees more than stock. Min airflow is set to 3.16 and average idle adaptive advance is very close to zero. I wouldn't say that it idles any smoother but I do get more vacuum - around 58kpa vs 62kpa.

[5_Liter_Eater]

Haven't seen that and not sure why it would go into REP mode. Look at engine diags, general. The tests there are what would cause you to go into REP (reduced engine power). Try increasing P0068 to ~1000.

[mdmbkr]

So for the P0068 test is it checking that the MAP reading corresponds reasonably well to the TPS reading? As in, a poor vacuum at idle would cause the test to fail? Will definitely try your recommendation.

[5_Liter_Eater]

The main idea behind the P0101, 0106, 0121 and 0068 tests are to ensure that the ETC is not in a runaway state. Thats why I don't know why you'd be encountering it at idle.

[mdmbkr]

OK, I made the recommended changes and no longer get reduced performance. Thanks!

My AFR at idle was very rich, and all accounts that I've read seem to indicate that a cammed car will typically idle lean. I reduced the VE in the idle area until it idles around 10% lean and that's also helped quite a bit with idle quality.

Now it's stable at 900 rpm and I'm fairly happy with that.

[jetttstream]

5 L E,
Thanks for the thread/typing up the procedure.

I used it on a cam/header install and has worked out quite well.

[5_Liter_Eater]

Beauty. Glad to hear it. I'm working on a simpler process.

[carlrx7]

lol, i got my cam to idle so well, i went back to stock so i could hear the lope again! lol im gonna try for 650 this weekend

[5_Liter_Eater]

I updated the procedure for 2.23 and refined it a bit based on re-doing my idle yesterday. Still back on post 85.

http://www.hptuners.com/forum/showpo...3&postcount=85

[carlrx7]

was the config updated as well?

[5_Liter_Eater]

Yea. The only change was to use dynamic airflow. The old one used ve airflow.

[carlrx7]

nice, will use again for my new turbo cam.. =)

[BluV]

I am not on the beta - so I cannot open the config.

Can you post the items/details of your config so I can recreate in 2.22 (released version of the software) ?

Thanks

[Google]

Make your table display look like this and save the config in 2.22