RickyMartinZ28

iTrader: (5)

I've got the idle exactly where I want on startup and in open loop. Once the car warms completely up it goes into closed loop and the idle increases and sounds like timing is changing as well...

Is there a way to always command open loop when TPS @ 0% ?

Or, does anyone have any ideas? I'm no pro, but I'm having issues with tuning the idle and getting it where I want in closed loop...

Higgs Boson

iTrader: (3)

There is a way but it only works on Vettes, not Camaros. You need to tune your O2 sensor tables, idle proportional tables, switching tables, etc in the Fueling Tab (HPT). It is a PITA, IMO, to get it right with LTs and a bigger cam so I set mine to idle in OL, but recently said screw it and just went OL full time (Vette). It actually runs much better everywhere. I'll leave it.

SSpdDmon

iTrader: (10)

If idle increases when the car is warm (beyond what is commanded in the tune), then I would look for a mechanical problem (i.e. too much airflow is being allowed into the motor either because the IAC is bottomed out or you have a vacuum leak). With higher RPMs comes a different spot in the timing map. It's possible that's the reason for the change in timing.

Closed loop is simply adjusting fuel. It shouldn't affect timing or airflow.

Higgs Boson

iTrader: (3)

That actually brings up a point of clarification. Is your idle slowly increasing steadily or does it jump up and down?

RickyMartinZ28

iTrader: (5)

Just suddenly increases by about 100 rpm when it enters closed loop... it's odd, I'm still experimenting.

BTW, I'm running 44* of timing at idle currently.... no knock, very smooth...

edcmat-l1

iTrader: (10)

Holy sheep **** batman! That's a lot of timing! How big is the cam? The most I've ever had to run is about 35 degrees, and that was in a solid roller with some crazy duration.

RickyMartinZ28

iTrader: (5)

Stupid question, but would not having the EGR blocked off cause this issue?


It's a decent size cam, it's a custom grind from CompCams. With the timing, fueling, etc, the lope is almost non-existent. It's been tricky to get the idle correct. But driveability is perfect... Seems like I either have way too much lope, or none at all. If I get the idle nice, then it's hard to start. It's been a real pain.

SSpdDmon

iTrader: (10)

Getting the car to start is more of an airflow problem more often than not. I bet that car would idle just fine near 30*. Drive-ability typically improves with less timing (specifically speaking about low airflow/low rpm scenarios). It's too much for me to try to explain at the moment. But, try an experiment in a big open parking lot driving around in 1st gear at 1500rpm. Lock the timing in at 30* the first time, then lock it in at 15* the second time. My money says the car drives smooth as butter at 15* of timing with less than 1800rpm and less than .22 grams/cyl of airflow.

joecar

Yes, it's an airleak, either into the exhaust manifold/header ahead of the NBO2's, or into the intake manifold after the MAF.

RickyMartinZ28

iTrader: (5)

The EGR is disabled, but still 100% intact. I'm about to order some block plates, I totally forgot about this until I started messing with idle the other day.

RickyMartinZ28

iTrader: (5)

Also, lowered to 35* last night, made the idle more choppy, still not where I want to be. Gonna wait for my egr plates to get here then tinker some more.