Taking the mystery out of tuning the 1.4

[ScarabEpic22]

So after thinking about this thread for a couple days I decided when I was down to about 8 gallons to top it off with about 4 gallons of E85. My 'back of the napkin' math says that I should have a tank of about 97 octane fuel, and I believe it. It feels like it's pulling harder, and looking at the timing on the Ultragauge it is holding the full advance where it often wouldn't before on 92 octane.

Sooo I got to thinking about those with E85 tunes and wondering just how hard is it to tune for this stuff. Well I did some reading on the HPTuner forum and it actually sounds really easy. I was thinking I'd have to change not only the stoich table but also mess around with a bunch of other fueling tables as well, but fear not, it's not nearly that complicated. You only have to change one table and it's not the one I was thinking.

Here is an excerpt from a thread over at HPTuners:

"When you switch to e85, you have to tell the computer to increase the fuel delivery to make the initial mix 9.8:1. If you change the stoich setting in HPT, you must also change other fueling tables to make sure the calculations stay correct. A simpler method is to tell the injectors to just deliver more fuel. This keeps all the other calculations correct, and only requires changing one table. The rule of thumb is usually to start out by telling the injectors to deliver 30% more fuel, and then tweak from there"

Easy peasy. In fact, that got me thinking back to when I installed the 42 lb injectors and couldn't figure out why MPFab's injector table was so different than mine, if he's running E85 that would explain it.

So, to update your tune for E85 should only take a few log/adjust cycles to get it sorted out and then you can start playing around with more airflow (boost) or start jacking up the timing. I'm not 100% sure I want to run E85 but if I decide to it's nice to know how simple it is!

Stew- This is definitely one way to do it, but this is getting into the "*******" a tune methodoloy...since you're tricking the ECM into thinking it's flowing less fuel (therfore commanding more), there are potentially other modifiers that will come into play. Definitely the quickest and easiest way to try it out as a quick baseline, but I'd really recommend getting a wideband O2 on your car before playing with fueling changes like this. Innovate LC1 is pretty good and cheap, was $150 a few years back so cant imagine they're much more now.

Just changing the stoich table would be the way that requires minimal tweaking to a good, 91-92 octane tune. Since we can assume the airflow model (and therefore fueling) with 92 is correct, changing to a different fuel requires changing the stoich setting and a few other tables (as mentioned above). Then you can start playing with timing and/or boost.

Here comes the BUT, you have to constantly flash tunes when you switch fuel types (AND reprogram the spark tables initially).

If instead you went to the flex fuel sender and wired it into the ECM, the ECM will switch on the fly for you as it will change the stoich point automatically based on what ethanol % it reads (note the stoich table axis is ethanol %). Also, this will use the spark biasing parameters (there are a handful) to either be a correction factor or a blanket #. Check out Spark->Advance then Spark Correction->AFR Correction and Misc->Flex Fuel to start.

Look at the Open Loop section under Fuel->Open & Closed Loop, there are some Alcohol biasing tables for OL operation that will definitely come into play with this.


I like the thinking, people like you who keep playing with it and reporting back are what drives us all forward!

And I only run 91-92 in mine now, ran 87 for the first 7-8k then put a tank of premium in. Big difference, for the extra $1-2 per tank Ill take the extra power and mileage is the same or slightly better.

Making me wish I could program around the BOV with hptuners. Tinkering sounds fun but I can't give up the pssshhhtttt every time I shift

I'll start playing with it soon enough John. Might need to pick one up and play with it, have to be a winter project though.

 

[Stew]

Thanks for the insight Erik, that's good info, I would rather be tuning correctly rather than taking shortcuts.

You know, I need to find some instructional books on tuning to strengthen my tuning knowledge 'foundation'; if you, (or Scot or other SOF members) has some suggestions for reading material that is relatively up to date, I would be appreciative!

As always, thanks a bunch!
Stewart

 

[cndctrdj]

having a little trouble with the tune. get surging or a dead spot at 0-5% throttle comming off vacuum and into boost
also my injector duty cycle seems way off at 45%

https://docs.google.com/file/d/0B7NaKuZT2i6BakJnS1E5WmxUYnc/edit

 

[rcmn0022]

having a little trouble with the tune. get surging or a dead spot at 0-5% throttle comming off vacuum and into boost
also my injector duty cycle seems way off at 45%

https://docs.google.com/file/d/0B7NaKuZT2i6BakJnS1E5WmxUYnc/edit

I'd bet that the surging is related to the fuel trims being way off. My best guess is an air leak, either in the intake or the exhaust. Try disabling MAF temporarily by swapping the high fail and low fail Hz for the sensor. If this fixes the hesitation, then you have an air leak somewhere or you may need to tune the MAF curve.

The PID you are looking at is half of the typical IDC, basically doubling that number will work, or create a custom PID, [PID.6200.ms]*[PID.12]/1200

 

[cndctrdj]

Thank you so much.

The surging started when I took off the trifecta tune. I assumed it was tune related

Also we never touched the fuel trims. They should be stock unless trifecta had some residue left behind

 

[Nick@RebelAutoWorxs]

Thank you so much.

The surging started when I took off the trifecta tune. I assumed it was tune related

Also we never touched the fuel trims. They should be stock unless trifecta had some residue left behind

When I mentioned the fuel trims, you cannot directly change them. It is the ECU self correcting for the errors in the tune or the engine itself. I'd look for vacuum leaks first since if the MAF is off and you correct it but you have any leaks, then you will have to correct the MAF again.

If there is a leak, the leak can be tuned out by Trifecta or anyone for that matter but you will start to notice some small hesitations if you try to quickly change the demand of the engine.

Some places to get a leak would be the valve cover rupture disc, charge piping, loose vacuum lines, intake piping, etc.

 

[cndctrdj]

Thanks. I'll start to look for vac leaks

 

[cndctrdj]

What is everyone enabling or disabling to make the Bov run with no cels?

 

[rcmn0022]

I'm not aware that anyone was running a bov on HPTUNERS or EFILive.

I'm going to go out on a limb and say that I believe ScarabEpic22 was looking into making it work but I could be crazy. Maybe MPFab might have looked into it well.

 

[cndctrdj]

Thanks for the heads up. I know people are running them just want to know how to enable them


Also found this
http://www.hptuners.com/forum/showthread.php?44292-sonic-1-4t-tuning-experience

 

[NewZJ]

Trifecta has the tuning to run BOV, I hope it can be done without trifecta but I don't know anybody that has

 

[ScarabEpic22]

I'm not aware that anyone was running a bov on HPTUNERS or EFILive.

I'm going to go out on a limb and say that I believe ScarabEpic22 was looking into making it work but I could be crazy. Maybe MPFab might have looked into it well.

It's on my to-do list, but wont be happening anytime soon. Maybe beginning of next year if I have a few things squared away by then.


Fuel trims are directly related to the MAF and VVE coefficients, once you have verified you do not have any vacuum leaks then I'd start looking at the tune (or lack thereof with aftermarket parts).

 

[cndctrdj]

I'll know exactly what's wrong by 6:15 tonight. Then I'll have to worry about everything else after that

 

['12Eco]

Stew,

Just an FYI, Although the max boost table says it is controlled by engine coolant temp it is mislabeled and is actually max boost by manifold air temp

 

[Flyer]

I'd like some help with this if anyone has a the answer.

2 things I'm looking for:

EQ ratio modifier table, In my PE table, I'm commanding 11.5 but it goes as rich as 11.14.

Boost table that limits by RPM. It falls about 20-25 kpa from 4k to 6300k.

Any help would be GREATLY appreciated.

 

[CheapFuneral]

Can anyone tell me how a tune is adjusted to work with a larger intake like zzp without the insert?


If I die, bury me in my truck, because it's never been in a hole it can't get out of!

 

[Flyer]

Can anyone tell me how a tune is adjusted to work with a larger intake like zzp without the insert?


If I die, bury me in my truck, because it's never been in a hole it can't get out of!

MAF table adjusted to new fuel trims.

 

[ScarabEpic22]

I'd like some help with this if anyone has a the answer.

2 things I'm looking for:

EQ ratio modifier table, In my PE table, I'm commanding 11.5 but it goes as rich as 11.14.

Boost table that limits by RPM. It falls about 20-25 kpa from 4k to 6300k.

Any help would be GREATLY appreciated.

How do your MAF curve/VVE coeffs look? I.e. Is your airflow model calibrated correctly? If it isnt, commanded/desired PE will never equal actual.

Get the MAF/VVE coeffs dialed in, then you can command whatever you want in the PE table and get it.

Also look at COT (Cat OverTemp) if you havent, repeated WOT pulls usually has the ECM hit it's predefined temp limits and dump fuel to "save" the cat.


For the boost limit, have a log of it happening? I would also like to see the tune if you dont mind, might be able to see something looking at the tune/log combo. Are you hitting a TQ limit, what's your commanded v actual TQ?

 

[Flyer]

How do your MAF curve/VVE coeffs look? I.e. Is your airflow model calibrated correctly? If it isnt, commanded/desired PE will never equal actual.

Get the MAF/VVE coeffs dialed in, then you can command whatever you want in the PE table and get it.

Also look at COT (Cat OverTemp) if you havent, repeated WOT pulls usually has the ECM hit it's predefined temp limits and dump fuel to "save" the cat.


For the boost limit, have a log of it happening? I would also like to see the tune if you dont mind, might be able to see something looking at the tune/log combo. Are you hitting a TQ limit, what's your commanded v actual TQ?

I haven't been logging commanded torque, but I'm pretty sure I'm not hitting it. I'll upload a current tune to HPTuners forum sometime today in THIS thread. I have logs of it happening and a very similar tune already uploaded in THIS thread.

Thanks for the reply.

The commanded AFR is what's dropping so low. I'm not logging with a wideband yet. I've got to replace the downpipe so I can get a bung. Also, I don't see the need to until I get the small things ironed out.

I have not messed with any MAF tables. If by VVE Coeffs you mean the equivelance of the VE table, no. I'd love to be able to though, but the Tunercats deal doesn't work on this file since it doesn't have some of the tables it looks for. Please school me on the VVE tuning though (links are good with me).

 

[ScarabEpic22]

Re-reading your previous post, I think your question is why is my commanded EQ ratio (via tables) not equal to what the ECM is commanding (via logs). It could be a few things like TQ limit, COT protection, a modifier table, etc that are impacting what the ECM commands.

If your question is regarding actual output know that without a wideband, you're shooting in the dark. Get that bung installed in your downpipe, log it, and correct the fueling. If you havent touched the MAF or VVE Coeffs, I'm betting you'll have some work to do...

Look at BlueCat's EQ_VE tool LINK, it will show you the VVE Coeffs as a simulated VE table and make tuning much simpler. Also, in the 2.25 beta, HPT has this built-in but it is just a view currently. Cant edit and get the updated coeffs yet, still have to use EQ_VE for that.

I'll try to look at the tune later tonight or this weekend.