Taking a shot at fixing a shitty tune...my first tuning experience_09_ctsV_6MT

[adam112]

I'm new to this forum, coming over from ctsvowners. I have a 2009 ctsV TR6060 car.

I recently discovered that my tune is complete shit and am beginning to work through a total overhaul. I am a Mechanical Engineer and with the help of this and other forums I am confident I can get my car running right.

Mods: Stock cam/heads LSA, CAI, lid spacer, headers, e85, making 11.5 lbs, ID1050Xs, Drop Ins and BAP, AEM Wideband

The MAF curve for my car is way off, VE turned off. I have large operating ranges with 20-30% positive total trims.

Injector data isn?t correct.

Low Octane matches High Octane which contains e80 spark, so I?m not safe on flex/93 ratios as I should be.

I have setup my scanner to dial in VE and MAF via EQ %error as my next step.

I have a stock file I have been comparing against. My PE hot table is stock for alcohol and gas. This is making me scratch my head?Was the MAF manipulated to get the desired EQ ratio on the dyno?
The attached log shows a 3rd gear hit at 5:20 in (the file is only 5:35, so its at the end) In the log, I?m taking large trims into WOT and lambda is right around where it should be commanded for flex from what I have read. I didn?t log commanded EQ on this file. I have that channel added now and can log on the way home today.

Can anyone suggest how/why my PE tables are stock? I am to the point of going out this weekend and working on the airflow parameters and want to avoid a catastrophe. I plan to dial in airflow and richen up PE before any WOT with adjusted MAF curve.

[jsllc]

You will want to log cyl airmass and injector tip temp. Common to make spark tables the same even though I do not. I usually tune the high, transfer to the low and subtract 3 or 4 from low table. With CAI you will always have to change MAF. Your flex fuel tables are separate and modify the timing in the high table based on ethanol content. So High should be tuned for 91 or 93 then add for the ethanol if you want to run a single tune. This will however not be as good as running 2 different tunes.

[johnny_boii]

If I was in this situation I would treat it like it was a new car and start from the beginning. Dial in the VVE table then the MAF and the begin to tune WOT. I always set the low octane table about 6 lower than the high just for safety. Be sure to get the injector data updated and corrected or you will be chasing your tail. For the flex fuel tuning I recommend leaving the high octane set up for premium fuel in your area, and then using the Flex Fuel spark table to add or subtract timing.

[adam112]

Thanks for the input guys! I will basically be starting over. Low octane will be dialed back for safety. Going to dial in MAF and VVE. Plan on putting a few degrees of flex spark in the flex adder and a few more in PE/COT adder.

Looking forward to getting her running better. Thanks again!

[OneTwo]

Your car and mine are similar. Mine is:

2009 CTSV - Automatic
ZL1 Lid, ID 1050X, e85 flex fuel kit, 2.4 upper making 14psi boost, K&N drop in, Corsa cat-back. I have been working on my tune for quite some time and have had pretty good success. Let me know if you want to compare notes.

[adam112]

^^Thanks OneTwo, I'd be down for that.

I have a file laid out to flash tomorrow and tune airflow (fingers crossed), conservative timing and Enrich values. That said, I will likely encounter issues and be posting up, haha.

[adam112]

You will want to log cyl airmass and injector tip temp. Common to make spark tables the same even though I do not. I usually tune the high, transfer to the low and subtract 3 or 4 from low table. With CAI you will always have to change MAF. Your flex fuel tables are separate and modify the timing in the high table based on ethanol content. So High should be tuned for 91 or 93 then add for the ethanol if you want to run a single tune. This will however not be as good as running 2 different tunes.

Im trying to follow what you said about the inj temp offset table in another thread here

So you set the cell for typical inj temp to 0 then log your formula to find a pw adjustment for the cells around it? How does this address the rich after reflash (isnt the ECM defaulting to a higher cell than the ones you are tuning)? And how do you achieve operating in different temp cells easily?

Thought I was all good to start dialing airflow tomorrow but now this has got me all thrown off...I'm going to dig into your formula further to understand it. My real job is getting in the way :/

[jsllc]

It is a chicken or the egg thing. They affect each other. Most cars seem to run 122 - 131F on injector tip temp. I pick one as my zero cell. In my case it was 122F. If you zero all of these (VERY BAD IDEA) the cells below will get progressively richer the further away from 122 and the cells above will get progressively leaner. Every car will run much hotter after heat soak. Do not be surprised to see injector tip temps of 165F+ after a car was sitting on a hot day. This table is an injector pulse width adder so usually below 122F they are minus values and above they are positive values. Now for me ... all of this "close enough is good enough system" is how hard you want to work at it. My cars I try to be within 1-3% under ALL environments. Anyone that says they do better is yanking your chain. This is not possible for cars tuned for customers. They will not pay for the 100 hours it takes to do this. I am no engineer but am a CS major with a mathematics minor so i can work the math and logic pretty well. Once I have good (not great) injector tip table I work on the MAF and filter so that MAF values only are populated +-10F of 122 injector tip temp. ESPECIALLY if WOT and PE.

When you log the inj temp it will work up from cold. I run until it starts filling in all the way through my zero cell (in my case 122F). This is done at a constant RPM with NO throttle change so you do not have to worry about transient. You can use the controls section to force the car to idle a 1000 or 1100 to move the process along. I put those in Excel and subtract the value found in my zero cell from all those below. Then reflash the car with these values. This will force a very hot inj temp. Log and it will walk its way down to 131 take the value you had for 122 from the previous log and subtract it from all the values above. this should give you a pretty good table with just a couple of tries. The value from your zero cell is how far the the MAF is off at hertz value. Once you are happy with the values one above your zero cell and one below your zero cell and the rest are safe (not going lean) tune your MAF and SD/VVE.

I always to MAF first on GM because that is how it supposed to run plus I have formulas that build SD/VVE from and accurate MAF.

EASY , not!

[adam112]

EASY , not!

I appreciate your breakdown! I'm embracing the challenge, haha. Digesting all of this and spending all day tomorrow accomplishing what I can with the car.

In your formula correcting for the AEM WB (I have the same one), how did you calculate the .95 and 1.003 constants? I am going to think on this one more myself today and see if it comes to me. **

Thanks again!

**I'll do what GHuggins suggested, keeping up my RPMs in a 0stft area and comparing to wb...I could then swap in my own constants for the next iteration? Think I've got that right**

[GHuggins]

I may be speaking out of term here, but he came up with those corrections because the AEMs are setup to read that much leaner than what the fueling actually is - don't know if they do this for safety sake or what, but you can compare one of them to a lab grade - very expensive - wideband and they always will read that much leaner than what the air fuel actually is... I personally love the AEMs - only use my lab grade wideband for analog inputs now when I can't use the CAN network associated one - just had too much going on to wire up one of my AEMs for it's analog outputs

[adam112]

Glad I got the AEM then!

[adam112]

Cold start and the commanded EQ is super rich, wb reading close to stoich...as the engine warms up, the error drops dramatically. Why does the commanded EQ lean out steadily as car warms but WB stays consistent around stoich?

Maf only. IVT gain is set to stock. Thought I had forced open loop but clearly did not with STFT coming in.

[jsllc]

Did not post the tune so I cannot tell where the mistake is. So log has no value. You should log fuel system status. I have a good list of PIDs attached.

[jsllc]

I defer to an engineer much smarter that me on the subject. Dr. Mike. (posts on forum) who tells me that the AEM is more accurate. I do not know. What I do know is that the AEM WB shows it leaner than 14.7 where the stock NB and other WBs say 14.7. It is 3-5% depending on location in exhaust stream. Dr. Mike told me If i wanted to check the accuracy build a device and blow bottled CO2 slowly over the WB. WB should read 14.7. I did this with the AEM and it reads 14.7. I choose not to figure out the the discrepancy but rather to build a formula to make them even. On my car the formula uses the AEM as the basis and adjusts the NB -STFT/LTFT to match. This results in a 2-3% trim on STFT/LTFT If I run them at all. On a customer's I do it the other way around so I do not have to argue on these forums (Not that GHuggins and i disaggree on this) or explain to a customer or the next tuner, which there always is. I always use the WB info for PE.

[adam112]

Did not post the tune so I cannot tell where the mistake is. So log has no value. You should log fuel system status. I have a good list of PIDs attached.

Here's the file

[GHuggins]

Go back to stock VE tables, 0 out prediction coefficients, smooth entire MAF curve 35 times to smooth it out then start making corrections again... Try to get as much steady state slow moving throttle progressions as possible... Killing lt ft's will help keep PE corrections separate from regular fueling corrections too...

[jsllc]

Okay MAF is off 20+%. What CAI did you use? Whom ever did this did it wrong. Your STFT are at MAX add now and then and LTFT are off so it is have lean issues. If you have a STOCK tune for car post it as well. Really need to know the CAI type and size of pipe the MAF is installed in.

[adam112]

Okay MAF is off 20+%. What CAI did you use? Whom ever did this did it wrong. Your STFT are at MAX add now and then and LTFT are off so it is have lean issues. If you have a STOCK tune for car post it as well. Really need to know the CAI type and size of pipe the MAF is installed in.

4" D3 CAI...not a well liked one among V owners, it came on the car. I installed a 7:1 honeycomb with 1/8" cells 3.5" before MAF, this is right after a 90 deg bend. It just dawned on me that the file I posted was after several runs getting MAF data closer.

The changes to VVE were just messing around pasting from the VE calc table I made and VE stayed off Greg. All trims were off during the maf tuning I did. Turns out the injector Tip Temp today was 110 cruising. I think the MAF low is closer to correct now. Here is a log with driving, pe, idling at the end I turned CL back on, the NBs are lean to my wideband it looks like.

This file has the maf values for the first log, the attached log here has the MAF values from the file I posted previously...sorry for the confusion.

I've been filtering my maf eq error table by throttle slope 0 for +/- 500 ms and vehicle acceleration 0 +/- 500 ms too

**What I dont understand about the situation from the first log and maf numbers...the STFT are pegged at max, yet the wb eq and commanded eq get closer with time without any change in stft. wb is at stoich, commanded creeps leaner and leaner towards stoich, stft pegged...idle airflow or some IVT gain?

[jsllc]

In answer to your question it usually means they STFT are at MAX and the error is greater than that.

[jsllc]

So according to the tunes you gave me. Your current tune says the CAI is smaller in diameter than the stock tube. I find this hard to believe. Is it?