Awesome, thanks.

 

Did you learn anything that can be shared with others?

 

i learned that my rich idle was due to my piece of **** aftermarket header. Threw on a GM manifold and like magic, my afr is fixed:-\

 

I've been wondering if that's the issue. I kinda wonder if moving my NB O2 down the pipe a bit would fix it.

 

You just sold me that header!!!!

Since we're talking about mileage, how many you guys getting from a tank? I'm averaging just about 200 on a full tank. 60's,2.8, stupid other ****.

I think my so called dyno tuner sucks at life.

 

oops I didn't know it caused that. I just sold it because I needed $.
It didnt throw any codes or cause drivability issues.
It's not just that header. ive seen other brands do it as well. It doesn't hurt anything and wont throw a code.

And yes, your tuner probably does suck at life. Who tuned you? I get alot more than 200 per tank. Do you have HPtuners? I can help...

I think that should solve it. The bung is maybe placed too high up in the collector and may not be getting flow from all the runners?

 

200 per tank???????? You should be getting at least 250-275 mixed highway city, well over 300 pure highway

 

Tuned by Matt at tune time performance. 14* timing, car is slow as **** and runs stupid rich. I knew he sucked at tuning 3 days after it was tuned. Might I add, that's 200/tank without 1psi of boost. If I lay on it forget it.

I'm gonna order hpt soon enough.

 

You guys are going to want to tune your VE tables to stabilize your idle air fuel ratios and dial in your stft and ltft to as close to zero as you can, dont do this forever, but aim for -2-0 %stft. This will bring your idle afr and cruise afr's to become very stable. When I idle my AFR changes from 14.5-14.7 that is it, at cruise I have the VE table dialed in to give me a steady 14.7-14.9AFR, and it stays fairly steady, meaning it does not flash between the two numbers very much at all.
It is not worth changing the commanded stoich to a leaner afr!! Next after you have your VE tables dialed in, you will want to tune the timing, see what Omega is offering you as I know he too has had success. For me, alot more timing is not the answer, you have to balance the load with the timing because you can go to far advance and start to lose mileage. What happens is as you add timing you reduce EGT's, however, as you continue to increase timing you start to work against yourself and EGT's start to increase, this is very bad. I have seen motors burn out pistons because they tuned the part throttle timing wrong. Finally, smooth all of your timing out, BY HAND not selection. Smooth the timing to have no holes or drops and to smoothly transition between load changes.
This works for me as I average between 520km (327miles) a tank in town when I drive it nice ( meaning I watch the boost gauge, pick a higher gear and keep the vacum as high as possible under cruise), and pull 700-750km (450-472miles) a tank on the highway.

 

Hmm.. some good advice here. At what rpm do you set the high rpm disable for dynamic airflow?

 

That's exactly what my theory was, especially with how my header/collector is designed compared to the stock one. I might get an O2 extender or weld in the spare bung to test this.

Tried that, changing VE never did anything to my cruise/idle AFR unless I disabled STFT/LTFT. No matter what you program the car to run, your O2 sensor will add or subtract fuel according to what it thinks you need. I actually got the VE table so low the car would idle at 16-18 when I first started it up (before the O2 kicks in), but my driving AFR was still in the low 14s.

 

Dain, what header? has me curious on my new issue.

 

[QUOTE=Bika;3975016]oops I didn't know it caused that. I just sold it because I needed $.
It didnt throw any codes or cause drivability issues.
It's not just that header. ive seen other brands do it as well. It doesn't hurt anything and wont throw a code.

And yes, your tuner probably does suck at life. Who tuned you? I get alot more than 200 per tank. Do you have HPtuners? I can help...


willing to help me? same issues... getting about 240-250 miles on a tank....not city but far from highway.. ive got hptuners... just seems like i should be getting more idk

 

Clear Image Automotive.



Great header, but I wonder if the O2 isn't reading accurately due to the position of it.

 

nope...header is not the problem.

 

[/QUOTE]Tried that, changing VE never did anything to my cruise/idle AFR unless I disabled STFT/LTFT. No matter what you program the car to run, your O2 sensor will add or subtract fuel according to what it thinks you need. I actually got the VE table so low the car would idle at 16-18 when I first started it up (before the O2 kicks in), but my driving AFR was still in the low 14s.[/QUOTE]

That leads me to believe you have a problem in your system, due to the AFR being fine until the vehicle goes into closed loop and accepts the signal from the oxygen sensor. I would look for vacum leaks, poor spark plugs, dirty air filter and exhaust leaks. (remember you dont have to hear an exhaust leak for it to be their.)

My dynamic airflow is enabled at 2800rpm.

 

14* of timing is not enough. not enough timing can be as bad as too much timing. What are your AFR at idle, cruise, and w0t? unless you are for some f'd up reason getting knock with only 14* of timing, bump it up until you see a lil knock, then back it off 1*. Most cars i tune seem to like 20* unless they are on the meth then i can go more.

send me your scanner config, some data logs, and your tune. I will look at them.

Ive tuned cars with clear image header/dp combo and cobalt addiction that have weird idle afr.

 

Unknown on the afr, back when it was tuned it ran high 10's wot. I ported the blower and it leaned out some. Then I went back and he only adjusted the timing from 19* to 14* in hopes to revive my gas mileage. Haven't been back since.