VE/MAF tuning Q's. Negative fuel trims after.

[540gts]

Post the tune and any logs.

Ed M

Don't have any current logs but this is the current tune.
We looked at older logs and MAF was never working. but the car ran fine then started the extreme lean condition.

[540gts]

More info might help 383 LT1 4L60E, 390 ford 9", 3600 circle D converter, 24x LS1 2000 silverado pcm, Granitelli LS1 MAF sensor, Granitelli 255 LPH fuel p, Golen forged short block, 11.4 comp, diamond pistons, 195 AFR eliminator heads, 36 lb bosch injectors,58 mm TB, Pacesetter LT, ported LT1 intake, Comp cam custom 605/618 lift, 238/246 duration, 110 LSA, Comp Pro 1.6 rockers, thought you might need this, thanks again

[mowton]

Don't have any current logs but this is the current tune.
We looked at older logs and MAF was never working. but the car ran fine then started the extreme lean condition.

Without logs, based on the info provided, my first conclusion is you are defaulted into Speed Density because your MAF isn't working. If you change your P0101 DTC from no mil to mil first error, you should see a check engine light. As a result of this, you will be fueling exclusively from the VE table. That is the first place I would look.

I would also suggest starting another Thread as to not "hijack" as you say the thread.

Ed M

[540gts]

thanks for the help, I will start a new one with log.

[1965 ssvert]

I am going to read up on the filters here in a bit.
Right now as far as the tune goes...I am ready to throw in the towel, but just can't leave it alone. I tried setting the open loop table to 1 in the area we discussed and went out and tried calibrating the MAF again. Seemed like it was all dialed in so I flashed the new table into my regular tune and drove home....trimming fuel and reading lean at the wideband. LTFTs no where near zero. Figured it must be the VE table I played with prior. Went out and got that where it seemed pretty close. Flashed it back into my regular tune. Still trimming fuel in CL!!! scaled the VE table down 6%, since I had scaled it up in prior attempts, not much change. Scaled it down 6% more just hoping to see a massive change. I then changed the open loop EQ table to match my tune file EQ table to rule that out, you guessed it, same thing. I then flashed the stock VE table and MAF table back into the tune. Still reading lean at the wideband, but trimming near zero on LTFTs and STFTs at idle according to the factory O2s. I multiplied the commanded lambda vs. actual lambda PID by .92 to compensate for wideband showing 8% lean when the fuel trims were near zero. I figured if I at least matched the factory O2s at idle maybe I would end up with an accurate lambda error reading to use for MAF and VE tuning. Tried nailing down the MAF again, too far positive, then negative, then started using the paste special multiply by 1/2%. It is fairly close in the lower hz then jumps into the teens (% wise) towards the 4000hz mark. I ended up throwing the stock tables back in again. The fuel trims aren't great in the higher hz regions with the stock table, but neither were my calibrated tables. I don't even know whether to trust the stock O2s or the wideband at this point.
Maybe I have a massive vacuum leak or another issue. I feel like I should have been able to pull it in by now, but just wasting time and fuel making the stock tables worse I feel. I took so many logs I can't even decide which ones to post to describe the situation. I am just at a loss. Is there possibly another table I am missing that would be messing with my CL fuel trims? Can I change the factory O2 switching points to fool the O2s and get the wideband readings I want?

[1965 ssvert]

It looks like compensating for the 8% error on the wideband and turning off the DFCO is going to help tremendously tuning in OL. At least my wideband vs. commanded error is reading 1 when 1 is the commanded lambda and the trims are near zero. I am also finding it easier to check my progress in CL with the LTFTs off in the CL tune and just logging the short terms as a check for what has been done in OL. I am hoping to add some good filters on the histograms as well and give it another go around from the beginning. Ed, I should have paid more attention when you mentioned it looked like I had a 5% offset in my wideband reading. It all zeros in around 8%. Am I right in thinking a good starting point is when my wideband vs. commanded error is reading 1 and my commanded is 1 and my fuel trims are switching either side of zero in CL? I feel at this point I can trust the wideband vs. commanded error PID as a multiplier for my MAF and VE tables in open loop.

[mowton]

It looks like compensating for the 8% error on the wideband and turning off the DFCO is going to help tremendously tuning in OL. At least my wideband vs. commanded error is reading 1 when 1 is the commanded lambda and the trims are near zero. I am also finding it easier to check my progress in CL with the LTFTs off in the CL tune and just logging the short terms as a check for what has been done in OL. I am hoping to add some good filters on the histograms as well and give it another go around from the beginning. Ed, I should have paid more attention when you mentioned it looked like I had a 5% offset in my wideband reading. It all zeros in around 8%. Am I right in thinking a good starting point is when my wideband vs. commanded error is reading 1 and my commanded is 1 and my fuel trims are switching either side of zero in CL? I feel at this point I can trust the wideband vs. commanded error PID as a multiplier for my MAF and VE tables in open loop.

Sometimes I forget what thread I am in. Should have posted this info as well. Great free downloads from the Tuning School for setting up the wideband. You will use the offset adjustments in the excel file (attached) to bring your WB input in line with your narrowbands when running in closed loop. The wb will be bouncing about a bit, but just make sure it is toggling around the lambda 1 value similar to your narrowbands. That is how I do the final tweak to the HPTiners WB O2 User Defined Aux input slop with the excel worksheet.

Ed M

[c.u]

This will show you how to use there Wideband_offset.http://www.thetuningschool.com/downl...p_wideband.wmv

[1965 ssvert]

Thanks guys. I had compensated at the lambda error PID, but that tutorial showed me how to compensate at the wideband input and eliminate the compensation at the lambda error PID. It also got me setup with the wideband in the chart and gauges. Everything looks to be in line now...sweet!

Now I just need to wrap my head around the dx/dy filters and figure out which ones are the best to use for VE and MAF tuning. I know how to put them into the histogram configuration now and have seen some examples, just need to do some more digging to figure out the best one to use.

[RonSSnova]

Good job. Now you can tune mine

[mowton]

Good job. Now you can tune mine

We all learn together

[RonSSnova]

With E85 in the tank, and a turbo under the hood, I have a big task in front of me. I've had to go back 5 iterations and rethink the process. I got lost.
I put it in closed loop just to have a look at trims and it surged badly just off idle.
My car is very loud which makes drive around tuning quite difficult, esp since I live in the middle of the city.
Ron

[1965 ssvert]

Ron, what I have come out of this thread with is the importance to have something trusted to compare your wideband with before it is trusted to tune off of exclusively. In my case my OL calibrations were fighting my CL operation due to the offset, not helping CL get closer like they should have been.

Might mean going to a shop that has a high dollar wideband to compare and modify your offset to match ( I used the numbers from the manufacturer, calibrated to free air and was still off). Maybe even find a stock car that will trim close to zero to plug HP into and your wideband so that you can tweak the equation.

I would find it hard to trust a wideband now without doing something like this, especially on a custom setup that I never planned on putting back into CL.

Definitely a learning experience to gain the learned experience ....and it is just the beginning

[mowton]

Ron, what I have come out of this thread with is the importance to have something trusted to compare your wideband with before it is trusted to tune off of exclusively. In my case my OL calibrations were fighting my CL operation due to the offset, not helping CL get closer like they should have been.

That is why I recommend connecting the WB to your car when both narrow bands are operating in the Closed Loop mode thus maintaining a Lambda 1 AFR. Your WB should be reading, on average, the same. Any difference is an offset and you tweak the WB User Configuration offset values to bring in line.

Ed M

[RonSSnova]

Hey guys,

First I needed to get CL working. Tried to outsmart myself and convert all of the CL parameters from the orig file which was a 5.7 Camaro to the 99 5.3 truck settings. That was a mistake. When I converted all that back to the 5.7 numbers, CL works fine.

So I set the tune up to go o closed loop at 150F and went for a short drive. My WB was reading 2% rich on the lambda scale.
So I went into the User defined config for my AFX and added 3% to the offset. Went for a drive, and now the AF is 1% lean, so 2 is the number.

STFT were all positive, which makes sense. STFT are also hard to learn from as far as I can tell. Unless you can get good steady state data. I also seem to have an offset between the NB's, but not all the time. They are original to the 99 Camaro harness and PCM I bought. I should tighten the exh Vbands, haven't done that since first running the car.

Anyway, I now think I can trust he WB. I might even be able to get away with simply richening the entire VE table by 2% as a start.

FWIW, a buddy got fed up and bought a bottle of test gas, checked several LC1 sensors and found them to be approx. 6% off. They read rich........

Next step for me is to get a speed sensor in the car. There are a few things that rely on it tuning wise!

I agree with ssvert, wouldn't it be nice to have a lab grace WB to compare to. I even wonder exactly how close one NB is to another......

Ron