Fuel curve tuning!

[Redog]

OK I fixed my Evap Purge Soilnoid about 2 weeks ago and now the car runs a bit rich, but also still leans out.

Story: On a cold engine I'll start driving and then at crusing speed, around 2000 RPM's the WB A/F will show 17.0, all red, and the car will be driving like it has 3,000 lbs in the trunk, quick slap of the gas pedal and it will unlean and go rich. It used to go back to say 13's then try leaning out again and get into the high 16's before going back to a normal A/F range, but now it does that but it also will stay rich and be running in the 11's even at idle.

Once the car is warm, it will still from time to time do the 17 A/F thing, but go back with a gas pedal slap.

Any idea of what to look at in HP tuners?

[MMGT1]

Can you post a log and your current tune? HP format is good, I use HP as well. What mods are done?

[[ion] C2]

You need to set up histograms.

[Redog]

How do I set those up?

[MMGT1]

Here is a fuel trim set-up. You need to add it to both your main table and your histo.
http://i823.photobucket.com/albums/zz159/MMGT1/FuelTrimSetUp.jpg

[Redog]

n00b brain!!

What sets do I need to do for that? I've never seen that page before :eek:

[MMGT1]

Without a scan loaded, just the scaner open, RT click on the Main Table. At the bottom you will see "Configure User Defined" The above table will open.

Then open your histogram view, to the RT of the last histo number there is a "histogram configuration" tab. Click that one and the other one pic'd above will open.

Just make yours look like those one's and then you need to add the "pid" you just made to your "main table". You can now view your fuel trims with long and short added so the changes you make to your MAF table are quick and accurate. Three or so runs and you will have your cruise nailed within a couple of %. I dont know how much tuning you have done so I dont wish to insult you with some really long winded answer, but if you need help with HP, ask away.

[[ion] C2]

Tune using your wideband, not STFT/LTFT readings.

[MMGT1]

WB is good for PE mode. I use NB to tune low end because our PCM will move trims as soon as NB is back in. Then the couple of % you are off in difference between the NB and WB gets carried into PE mode. NB is actually very effective at 14.7:1, or whatever it is reading 1 lambda at.
I should add though, this is if you are going to use your NB. If you are leaving the WB in place as a perminant install, then yes, no need for trim tuning like that.

[Redog]

OK so I finally got a scan and saved it (I did one on Saturday, but didn't save it correctly :( )

So I'm driving around the area and my a/f WB gauge goes once to 16.3 and then topped out again at 17.

So I'm looking at the scan chart and notice that the O2 B1S1 dropped out during this time, I mean it totally flatlined, but right before it flatlined, it peaked and stayed up for a period. So it's something with the O2 sensor.

What do I look at? The O2 sensor is pretty new. I replaced it this spring

[MMGT1]

Is this happening when you are not on the throttle, coasting to a stop? The PCM will cut fuel and timing when comming to a stop, that is normal. Once you are at a stop, fuel and timing will revert to your idle tables and then AFR should return to 14.7:1. Look at what your TPS is reading when this happens. Better yet, post the log and I will have a look and see if what you have going on is normal

[Redog]

Oh it's not normal, Yes it flatlines at idle which I know is OK, but is also does it while cruising.

The graph show me going in the 40's range, with the O2 sensor reading toplined, then flatlined :hanged: :panic:

[Redog]

I'll have to take a screen shot and show you what I'm dealing with. I'm getting a little worried about the car leaning out so much :(

[MMGT1]

Replace your crank position sensor and connector. The 7x sensor at the back of the engine. The connector leads from the sensor to the ignition module