I know there was a thread on it but I can't seem to come up with the magic combination of words to get the thread to pop up with the search function (I've tried for the past 30 minutes). Any help is appreciated. Thank you.

 

'cam idle' worked for me.
http://www.forums.evolutionm.net/sho...m+idle+advance

although i dont agree with as much advance as it recomends

 

1) Increase idle speed to 1000/1100rpm in neutral 1200/1300 w/ AC on.. This can vary depending on your mods, only raise it enough to keep it from loading up.

2) Add fuel at the idle load cells until your Fuel trims are close to 0% (100% in Evoscan)

3) Add a bit of timing *ONLY* if the above two things don't really help, Timing changes HC and NOx emissions at idle, especially with cams.. But I have found 11-12 degrees cooperates best if you need any.. Over that, and you run the risk of throwing P0300 occasionally at low load cruising around at near idle speeds..

USe the BISS adjustment as a last resort, basically if your Idle speed target in ECUFlash is off by a few hundred RPM, it means the BISS is out of adjustment, its generally hard to tell if the car is in closed loop, but if the RPM goes low, then gets higher, or goes high, then gets lower, then your BISS may need minor adjustment, since its a valve similar to the ISCV the settings between the two are cumulative.. When its adjusted correctly, it will hit the speed your looking for without hitting high then dropping, or hitting low then raising.. This will help a bit if you find your car returns to idle and drops a little low.. (Not the Lift-Vent anomoly that causes stalling, thats something different)

 

Any inputs on how to fix the "Lift-Vent" stalling issue? We get a real low idle (and sometimes stall) at the end of an Auto-x run. 03 with 272 cams, FP, 720 injectors, FMIC, etc.

 

We should really make this sticky, as the question will continue to come up as long as people are doing cam swaps.

Mods?

d

 

there will likely be no fix.. Most of the time its due to poorly designed intakes or venting your DV..

I found the first gen buschur intake would have that problem, when I flipped it around so the recirc fitting faced the turbo (under the intake instead of on top) the problem went away..

Basically, most of the issue is due to airflow confusing the sensor, either stalling the airflow or reversing, when you VTA, you vent air thats metered and it tries to compensate when it cant..

The correct solution is to tighten the DV valve slightly to prevent it from being open at idle, but that can lead to surge, the other alternative is to keep the turbo from surging, and the airflow recirculated as far from the MAF as possible.. Raising idle and maintaining more airflow through the sensor also helps.. clamping the idle value using an ECU+ or something similar also helps alot..

 

In your case you should look at the ISCV values, have them target for a larger value so when you come to a stop, it hovers at a slightly higher idle then drops to target..

 

Thanks Jack. Right now the car is running the stock intake box with a drop in filter, and a turbosmart DV on full recirc which is set tight enough so we do get a *bit* of surging.

Here are the ISCV values:

Desired ISCV initial step position with AC off - Drive:
-32 : 247
-8 : 163
7 : 133
20 : 121
34 : 100
50 : 82
77 : 23
82 : 7

Desired ISCV initial step position with AC off - Neutral:
-32 : 145
-8 : 131
7 : 122
20 : 113
34 : 95
50 : 68
77 : 13
82 : 7

Also to be noted, the injector scaling of this car is still at 513, but I'm going to scale that up to 640 or so with the next flash.

 

You might have to alter your scaling sooner than you think... Part of the problem without scaling is the fuel trims go way out of whack, there can be significant difference between higher RPM closed loop and idle, and that in turn can cause the engine to swing really rich, or really lean, and that can indeed result in a stall.. Loosen the DV slightly, you need to eliminate that surge too, surge will stall airflow in the intake and could stall the MAF sensor's reading (you can tell if its doing that if the sensor readings drop at idle, jump around high low high low, then resumes a normal reading..)

 

Good info. I'll flash in the bigger injector scaling first and see how that does this weekend on Sunday. I'll be pulling some logs from the car then as well.

 

did someone delete that thread? i can't find it anymore!

 

I have a car Im working on with a set of Revolvers in it......has anyone had experience working with them? the idle is terrible.... I got to idle reasonably well but as I sit at a stop light the idle slowly deteriorates. I set the idles the the same values stated earlier in this thread 1000/1100..... and increase the ISCV tables significantly and it seem to help, but Im not very familiar with these table yet, and need to read up on them... If I understand it right, the ISCV tables are the "over shoot" the car does then slowly bring it down the specified idle..... but as I said before... I need to read up on them.... any help is greatly appreciated.

 

I had revolvers. I upped the timing and opened up the biss. Both things I do not recommend. I just didn't have the knowledge at the time to try something else.

If nothing else works, and you don't see the cel as a problem, timing and biss did work. It took a lot of timing in my case.

 

^^^^Thanks...... I got it running ok just messing with the idle tables...I have a few more things I want to try, but just looking for some input before I half -hazardly go changing values :-) .... its running well it enough that if it was my car I would leave it alone, but the guy that owns the car what a moded car to run like a stock car......

Did you have adjustable cam gears? If so did you keep them at 0,0 or find any combination that helped with idle?


zze86 I didn't mean to jack your thread, but it seems as if you got the advice you needed and seemed like the appropriate topic to ask the question. We are both looking at a similar issue....

 

bump for more info on tuning large cams for idle