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

[1965 ssvert]

Fuel trims negative after MAF and VE calibration. Actual lambda ratio also shows lean according to the wideband reading.

Tuned MAF and VE according to Greg Banish's methods. They come in consistently within a few percent when isolated.

If scanning and I turn off fuel trim learn, closed loop, and reset fuel trims via vcm controls my lambda error settles down to within a few percent. Assuming it is then fueling primarily off of the MAF/VE tables. Re-enable learn, and closed loop and the fuel trims quickly relearn a 7-15% error. The wideband reads lean at this point about that much as well. The car runs well either way. I have driven it around in forced open loop as well as trimming the 7-15%. Long terms in the histogram don't show more than 8% on average.

I have changed the General>fuel>air fuel ratio>AFR stoich to 14.124 (currently set at this) as well as down to 13.93 (10-15% ethanol fuel around here). The error remains the same. When toggled in VCM editor things improve. I can't seem to find a table or multiplier that could be causing this in VCM editor. I have thought about scaling my injectors, but don't think that is a proper way to fix the problem. What am I missing?

Current tune as well as a log file with marks toggling between fuel trim learn/closed loop off and learn on/open loop on via vcm controls.

[mowton]

First question I always ask (please don't be offended) is did you truly isolate the 2 tune processes. Meaning, for MAF only tuning, setting the Dynamic High RPM disable to 400. For VE only setting the MAF High fail to 1, set DTC P0101,0102 and 0103 to Mil on first error (I leave the SES enable so I can see the MAF has failed) and set the Dynamic High RPM disable to 8000.

Also, make sure you have sufficient filters in your histograms to filter out decal, accel and transient pedal movements. These can "contaminate" your settings. You want only good steady state data to create your tune from.

After looking at the log, I would also add that I believe you have about 5-10% offset difference in your LC-1 settings. When you are in closed loop (narrow bands controlling the fueling), the LC-1 reads like 1.07/1.10 yet when you go open loop it reads between .98 and 1.02

Obviously need to do all the other open loop setups. If you post the tune files for each of the processes, we can apply a second set of eyes.

Ed M

[1965 ssvert]

please don't be offended

No offense taken. I just want to get this right.

I believe that the files are kosher for what you have asked about. The one exception on the MAF calibration file after scratching my head for a while is the Fuel-> OL/CL-> EQ F/A vs. Engine Coolant Temp vs. Map table. Greg's example had several tables here, named slightly differently and I didn't make the connection until now. I believe I need to set this table to 1 across the board for MAF calibration. It looks like according to the description that this is affecting my fueling in open loop while tuning the map and could account for the error we are seeing between OL and CL. My MAF calibration must be incorrect because of this.

The other discrepancy would be that Greg suggested setting MAF hz to zero instead of 1,should accomplish the same thing, for the MAF fail method as well as copying high octane values into the low table. He does not set the high rpm disable to 8000rpm in the video. What exactly does this accomplish and why was it left out if it is necessary? He doesn't use this method, so maybe he forgot to mention or didn't know about setting the high rpm disable to 8000rpm.

The alternate method he provides and uses for VE only calibration is setting the Hi and Lo MAP and TPS Deltas to 0 in lieu of failing the MAF.

I do have a couple of questions about that table though: What does F/A abbreviate? Is the table dividing 14.7 by the table value even if your General->stoich AFR is set to say... 14.1?

I have attached my non-MAF fail VE calibration file, MAF fail VE calibration file, and my MAF calibration file (without the OL EQ ratio set to 1) for review as requested. If that is in fact my problem, I will set it to 1 for another go around. Thanks!

[mowton]

I am out and will look at the files when I get home. As far as the f/a table you would set that at stoich up to the map where the pe would cut in and 176 degrees and up (operating temperature) think it stands for fuel air .

[1965 ssvert]

Forgot to add that I have no filters that I know of in my histograms. Greg didn't show how to set them up as he only advocates steady state dyno tuning. I am not sure what to input for filters. I can definitely see how they would be helpful. I tried to duplicate steady state with the best I have available at the moment...a long uphill stretch in order to keep my speeds low, change throttle input as little as possible through the range, and hold cells until they stabilized before moving to the next. No deceleration until the end when I would just clutch in and the rpms would quickly drop to idle making a very quick appearance in each cell on the way down.

I added the scan configuration I am using, in case you wanted to check for filters, which I believe I have none.

Thanks

[RonSSnova]

I would also like to see the formulas for these filters. I am having a heck of a time getting good steady state data while navigating city traffic. I did add one for off the throttle.

Ron

[mowton]

I do have a couple of questions about that table though: What does F/A abbreviate? Is the table dividing 14.7 by the table value even if your General->stoich AFR is set to say... 14.1?

It is a single table that covers all the temperature and MAP regions and defines the open loop EQ values (1/Lambda). Attached is a crude graphic showing the 3 main area's of the table. The PCM puts itself into open loop at cold start. This is where it gets its commanded EQ values to determine fueling. You would address this area if you were having cold start/run issues while still in open loop. Per your tune, at 92.5 *F, the PCM reverts to Closed Loop and uses the O2 sensor data to perform fueling adjustments by swinging rich to lean to rich etc. in an effort to maintain a Lambda 1 value. This is the area when you force open loop to tune that should be set to 1.0. The last area is the PE region which defines the fueling requirements when the PCM enters WOT, which is also an Open Loop operation. This you would set to 1.12/1.15 (NA) or 1.23/25 (FI). There is also a PE table (the real place that PE is set) and the PCM will take the richer of the 2 as required.

Per your question on the table and stoich values, yes they will adjust you stoich value in your tune which is the 14.1/EQ value. As a result of the numerous different fuel types out there, I tune exclusively in Lambda to do away with "guessing" what the alcohol content is of the fuel in the tank.

And Yes you will have to go back, set the Open Loop table to the 1.0 and redo the MAF and VE. Other than that, the tune files look ok for separate MAF and VE tuning. The 1 I use vs. Gregs 0 for the MAF High fail is a nit.

Hope this helps explain the table.

Ed M

F-A table explanation.jpg

[1965 ssvert]

Ed, breaking it into sections like that was golden. Thanks! That is definitely where my error is coming from.

Just to clarify: I only need to set the "normally closed loop area" to 1 for MAF tuning or should I also set the PE area to 1 (for tuning only) so I can tune the MAF into the PE area a little bit as well?

Do I also need to set these areas to 1 for the VE tuning? May be a dumb question. SD probably doesn't use this table as it is related to the MAF and that is what we are failing to tune in SD.

set the Dynamic High RPM disable to 8000

What exactly does this do. Is it just to make double sure that the pcm will not try to use MAF data during SD tuning? The description mentions "filtered MAF"?

I attached a screenshot of the table after I changed the values to 1. HPtuners description (at the bottom of the screenshot) refers to stoich value and then uses 14.7 as an example. I am tuning in lambda, but wouldn't the table use the stoich value under Engine->fuel->general->stoich AFR (mine is set to 14.124). I guess what you are saying, ED, is that it is all relative to lambda because it is a multiplied value?

Ron,

I am having a heck of a time getting good steady state data while navigating city traffic

I don't think it would be possible to get good steady state data in stop and go traffic and hit all the cells. I also am not an expert. I am however interested in your off the throttle filter. Mind posting it up?

[mowton]

Just to clarify: I only need to set the "normally closed loop area" to 1 for MAF tuning or should I also set the PE area to 1 (for tuning only) so I can tune the MAF into the PE area a little bit as well?

Yes you can set it to 1.0 but set the actual PE table desired PE. For an NA car it should be like 1.15 and FI 1.23 across the board. Remember to put the Open Loop table back to original after your tuning sessions are done.

Do I also need to set these areas to 1 for the VE tuning? May be a dumb question. SD probably doesn't use this table as it is related to the MAF and that is what we are failing to tune in SD.

Yes, you still want the commanded Lambda/AFR to be 1.0 for tuning purposes and the PE will kick in and be added as required. Regardless of the PE adder, you will still be tuning the base VE value to its required value.

What exactly does this do. Is it just to make double sure that the pcm will not try to use MAF data during SD tuning? The description mentions "filtered MAF"?

As the 400 rpm forces the fueling to be derived from the MAF only, the 8000 tells the pcm to continue looking at the MAF/VE hybrid until 8000 rpm. This is used when you use the "fail the MAF" approach to entering SD. Normally the fueling is a MAF/VE blended (Filtered MAF) from 0-4000 RPM and then MAF only up to 8000 RPM. It is just an extra precaution as you said to make sure the PCM continues to look at VE. Your approach should not need it.

Will address the filters tomorrow night....I'm tired :-O

Ed M

[RonSSnova]

I just did a run out I84 doing steady state where I could and some throttle rolls into boost (6.7 psi springs)
Got some good data, especially wanted to see the boost areas hit my commanded AFR. So thru 5000 I'm good now.

This is the filter I put in the AFR error Histogram.

[SENS.90] > 10 & [SENS.10] > 80

SENS.90 is the TPS sensor so less than 10% doesn't populate.
SENS.10 is ECT in Celsius so I don't capture warm up data. 176 degrees F.

You can add the filters after gathering the data btw.

The TPS filter pretty much requires a full throttle lift to work right. It's those gradual lifts that mess me up because my setup goes rich then.
110lb/hr injectors on E85. One more thing to figure out!

Ron

[1965 ssvert]

Thanks Ed. You are a treasure trove of very good information. I appreciate the detailed responses. I really would like to see some of your filter tricks if you end up finding time. No rush and don't feel obligated to do so, I think you have given me a few things to chew on for a while.

Ron,

So thru 5000 I'm good now

110lb/hr injectors on E85. One more thing to figure out!

If you don't have the injector data dialed in before doing your MAF and VE isn't it going to throw everything else out of whack when you do? Thanks for the filter equation to get me thinking.

[RonSSnova]

The ID1000's come with very detailed and accurate info.
I'm confident I have all that correct.

I know what to try, but one thing at a time or we get lost quick!

Rookies, ha!

ron

[mowton]

The ID1000's come with very detailed and accurate info.
I'm confident I have all that correct.

I know what to try, but one thing at a time or we get lost quick!

Rookies, ha!

ron

Ron,

What year PCM are you using the ID1000's in? Certain years, based on coding hard limits will need you to scale the injector data as well as all the airflow parameters. And yes, Injector Dynamics goes well beyond most injector suppliers with good, detailed data.

Ed M

[RonSSnova]

Hi Ed,
PCM is a 1999 Camaro SS
Ron

[mowton]

Hi Ed,
PCM is a 1999 Camaro SS
Ron

That's cool, plenty of IFR headroom. Should be good as long as you don't run out of MAF.

Ed M

[RonSSnova]

Ed, it's a 3 bar os, so there is no maf.

ssvert, sorry to hijack a bit here!

Ron

[1965 ssvert]

ssvert, sorry to hijack a bit here!

No worries, I'm learning from it too.....just glad Ed is posting up some solid info for us!

[mowton]

As far as the filters go, you want to set up parameters that will help isolate only the area of the log results which pertains to your tuning effort at the time. Some include, but are not limited to ECT at say 176 degrees (operating Temp), IAT at the points where you have set your spark correction not to pull timing, Commanded AFR can be used to filter out PE or non PE data, RPM/MAP to isolate specific load area's, MAP can be used to help filter out deceleration data by setting to say greater than 35-40 kPa and TPS for isolating idle from cruise or cruise from WOT etc.

Search Filters in the Help file and there are great tutorials on how to set them up. The nice thing about the filters is they can be created and used after the log has been completed. Just make sure you are logging all the required OIDS/Sensors you will need later to isolate any specific data you are looking for.

Hope this helps

Ed M

[540gts]

Hi Ed Not to high jack, but looks like you guys got some stuff fiquared out. We converted 95 Trans Am 383 LT1 to 24x LS1 coils and 2000 pcm. we were tuning and all was going great, then bout a week later I started getting a hard lean situation from about 1800 to 2200 rpm, my Inovate LC 2 guage pegs the AFR to lean and car almost dies. If I play with the throttle I can get it past the lean zone, then it revs out good and the AFR is good. I have replaced the MAF sensor and triple check it, on HP tuner it show 0 grams and 0 hrz when not running. When running grams show a constant 3.17 and 0 hrz. the MAF fail high is set at 14000 Hrz. any help would be greatly appreciated.

[mowton]

Hi Ed Not to high jack, but looks like you guys got some stuff fiquared out. We converted 95 Trans Am 383 LT1 to 24x LS1 coils and 2000 pcm. we were tuning and all was going great, then bout a week later I started getting a hard lean situation from about 1800 to 2200 rpm, my Inovate LC 2 guage pegs the AFR to lean and car almost dies. If I play with the throttle I can get it past the lean zone, then it revs out good and the AFR is good. I have replaced the MAF sensor and triple check it, on HP tuner it show 0 grams and 0 hrz when not running. When running grams show a constant 3.17 and 0 hrz. the MAF fail high is set at 14000 Hrz. any help would be greatly appreciated.

Post the tune and any logs.

Ed M