hrspwr

iTrader: (3)

I am currently tuning my car and am at the point where I am stumped.

In closed loop if I slowly open the throttle my narrowband O2 will go down to the mid 200mV range and then once PE comes in it will shoot back up to high 800's low 900's. The issue is once the O2 starts getting into the low 300's high 200 range, my knock count starts and it starts to remove timing. Now, I know I cannot tune properly with a narrowband O2, but something is definetly up with the way the tune is acting. Everything is pointing towards it is going lean. I have tried to increase AE in the lower Delta LV8 range with no change.

The other thing that I noticed was that when I am idling and the car is hot, my blm is at 110 and int is at 128( I know the ecm is pulling fuel due to a rich condition). My issue here is that the O2 reading swings between 330-400 instead of the high 500's. Why is it reading lean when it thinks it is rich, and why is it not adding fuel back? Is there something within the bin where I can tell what voltage the O2 should target for? This happens in both closed and open loop, but the O2 reading is different in open. In open loop the O2 reading is in the mid 600's to low 700's. Same with the above. The O2 reading will come down to the low 500's instead of the 200's.

I am currently running an arap bin with modified timing for vortec heads.

RBob

iTrader: (1)

You won't get any AE with a slow roll into the throttle.

> Is there something within the bin where I can tell what voltage the O2 should target for?

Yes, there are three tables: lower, upper, and mean for the O2 feedback targets.

What is the INT doing during this time? Also, be sure that the "reset INT with a BLM cell change" option flag isn't set. As that can prevent the INT from adding the required fuel.

RBob.

hrspwr

iTrader: (3)

After looking through all the flags and constants, I found that for AE to become active there has to be a load change of at least 20. I have not changed that.
I will take a look at those tables. What should they be set at? Should I shift them upwards to increase fuel, or should I tighten the lower and upper closer to the mean?
I cannot recall what is happening to the INT. I will look at my log and see what it is doing.

RBob

iTrader: (1)

AE is based on a change to the TPS or LV8 over time. A slow roll has very little change, so very little to no AE. In this case it is usually the INT that makes up for the lack of AE.

RBob.

hrspwr

iTrader: (3)

That is what I thought, and that is why there was no change when rolling into the throttle when I increased AE.

I took a look at the logs and it does not look like INT is doing much of anything. It may go down a number or two but that is it and stays there. Meanwhile the O2 is decreasing. Once it hits a certain spot the O2 will jump back up. On one slow roll in the INT and BLM stayed at a constant number until I stopped pressing the throttle and held a steady pedal, then the INT started to drop. It went from 128 to 121 within a second and O2 went from 570mv to 400mv.

The other thing I noticed is that even when I roll into the throttle, it looks like the O2 is swinging. It comes down, spikes up, comes down and then spikes again.

I am not able to find the tables you mentioned earlier either. The only thing that I can see is closed loop rich/lean threshold vs airflow and rich/lean offset vs coolant. Also the flag is not set for BLM change.

RBob

iTrader: (1)

The high/low oscillation of the O2 value is likely from being in closed loop. The ECM forces it.

From the ARAP hac here are the table names & addresses for the O2 target:

RBob.

hrspwr

iTrader: (3)

The values in the upper and lower tables, should they be closer to the mean, or should I shift the mean value up and then adjust the upper and lower according to the mean value?

RBob

iTrader: (1)

Try shifting all three by the same amount.

RBob.

hrspwr

iTrader: (3)

I tried moving all three table values down by 50mV and it looked like it ran better but it had once nice lean pop. The other thing I noticed is the O2 dipped even lower when rolling into the throttle.

I know I am still rich. My int is at 128 but my blm is at 120 for idle and light cruise areas. Would having the ecm pull fuel in cruise cause it to 'hesitate' to add fuel when rolling into the throttle?

Another question I have is my exhaust smells rich at idle, to the point where it will burn your eyes. I am not running an EGR valve, but do have a cat. I noticed if I pulled 2* of timing at idle the smell gets better, but the idle is choppier and shakes the car. With the timing pulled, it also has a stumble when trying to accelerate. Without pulling the timing, it runs great, but smells. I have also tried to pull fuel and lower timing with the same results(develops a stumble). Anything I can try here? I am running about 21-23* of timing at idle

RBob

iTrader: (1)

I'm going to say that there are areas that are lean and areas that are rich. The burning eye syndrome is usually caused by being lean. And as you pull timing (SA) the engine runs worse. Another sign that it is lean.

There may be some other factors here such as aftermarket injectors and/or a larger TB.

De-screened MAF by any chance?

You may need to work on the delta TPS% threshold for AE, along with working on the volume of AE.

RBob.

hrspwr

iTrader: (3)

Its funny because I thought that the burning eyes would be because it was Rich, not lean. If it is because its lean, that would make sense why pulling timing helped. The thing that I cannot figure out is if it is lean, why is it still pulling fuel? If I leave the tune in open loop the O2 mV is mid 700's and it still burns my eyes. Not sure what to make of it.

I have 24lb injectors in the car now, with stock FP. I also have runners and a baseplate, but the TB and plenum are stock.

MAF has both screens still in it.

Delta TPS% threshold, is that the same as LV8 to enable AE? I have increased AE as well.

Not sure if this makes a difference or not, and if I need to compensate for it, but I have moved my MAT sensor into the snorkel. Not sure if the lower air temps are causing it to put more fuel and then the O2 is trying to pull it.

I also do not have an air pump on the car. Would this also cause an issue if I had not tuned it out? If so, do I tune it out with the constants listed in the above posts?

RBob

iTrader: (1)

Delta TPS% AE is different then the delta LV8, throttle movement versus a change in load.

Moving the MAT will usually disable the EGR. Not much else. The ECM uses it as the temperature threshold to enable EGR. Note that the MAT is also used in the crank PW, ARAP adds fuel when the engine is really heat soaked.

Without the air pump you should set the CTS enable for it high. So it is always in divert mode. When in divert the ECM typically reduces the O2 window values (the three tables). So as the ECM switches the phantom AIR pump in & out of divert the O2 target will change.

Can also subtract that value from the O2 tables then 0 out the value. This also helps in that when you look at the values in the three O2 tables they will be the real target.

With the larger injectors should also reduce the proportional gains. They are only about 9% larger, but the proportional gains are tricky as it is.

RBob.

hrspwr

iTrader: (3)

I see, one is throttle movement to enable AE and one is LV8 based. Do both parameters have to be true in order for AE to be activated?

I set the AIR enable CTS temp to FF in the hex editor. Will also subtract the O2 out of the tables.

How do you adjust proportional gain?

hrspwr

iTrader: (3)

As a test I put in a AUJM bin and put conserved timing into it. With stock fueling I believe I saw what O2 swinging is suppose to look like (go high, INT will decrease, O2 mV comes down, INT returns to 128 and repeats). I then took out 10% fuel out of the MAF tables in idle and this stopped. My O2 is only moving ~120-140mV total while idling over a 30 second period of time. It only moves up or down 50-60mV tops at a given time. What would cause this? O2 thresholds are stock.

hrspwr

iTrader: (3)

Anyone?

hrspwr

iTrader: (3)

No one?

RBob

iTrader: (1)

Sluggish O2 sensor? Have you compared it to the other BIN.

RBob.

hrspwr

iTrader: (3)

Th aujm bin swings a lot more than the arap bin that I was using. It looks like it is coming around slowly. The only thing that I changed in the aujm bin to get it to work on my car was I took out the 100mV O2 offset, disabled AIR and EGR. That combination made the car feel better and the O2 start swinging(tried the above on the arap bin but did not help). I am now playing with fueling to get it dialed in and put conservative timing in the spark table.