NefMoto

So with my big turbo setup I've never been able to get it to run correctly at idle.  Without the maf plugged in it has an oscillating idle that sometimes like to go all the way up to 17 or 18.  With the maf plugged in its constantly lean at idle(18 afr), normal driving seems alright though.  I have the stock maf and housing attached to a flexible tube(until I have time to fiberglass an intake) and then that runs into the turbo inlet.  I also have a forge splitter, with the recirc part routed in after the maf but pre turbo.  I can take a picture if that would help.

I've tried adding fuel via kffvs (I know it's kind of a cop out for a bigger problem) and have upped my temina and teminva.  Do I have to rescale the maf tables?  I thought I wouldn't have to because i'm using the stock sensor and housing. 

What would you guys check or do?

I also have 870cc injectors installed with the correct tvub values, and i'm pretty sure my krkte is close (little less than .04).  My map sensor is reading too far in both directions it seems like too when I look at it with the torque app.  Could the silicone I used to seal it to the intake tube caused the sensor to go bad?

Has anyone bought a obd cable lately that works?  I've bought 2 before and both had the non-ftdi chip.  Currently I'm using a mpps clone.

What ecu is it?

Do you reach learning limits on fuel trims?

as far as OBD... Ross-tech cable can't be beat.

Its an 018ch out of an awm 2001 Audi a4.  Me7.5 wideband ecu.  I don't think I have the rear cat coded out completely so my fuel trims don't adapt correctly, I also don't have vvt but have turned it off in the eskonf but I still get a timing related error code. But I don't think that affects anything until I actually trip the timing error.

 Would you like to look at my file? 

Don't big turbo (you never said which, but based on your injectors..) setups need a larger maf housing?

From what I've read you do once you reach the stock maf gloe limit, or you can just go past it but you don't know how much air there really is.  But at idle it shouldn't flow all that much which should def be within stock limits.

And the turbo is a Garrett t04e I believe is the name.  T3/t4 50 trim.  Full 3in exhaust.  2.0t coilpacks (since my "unbreakable" bolt downs went bad), need to change my dwell time for them.  AEM uego

IMHO it is out of question if big turbo needs bigger MAF when we are talking about idle. It looks like your injector scaling is off, you should correct your issues with coding out catalysator and variable timing correctly and then dial your injectors...

Injector scaling as in which values? 

Without the maf the car runs pretty well.  Which leads me to believe that its a maf scaling problem of some sort, unless the wideband system is correcting my tuning flaws.  And since I don't have a reliable ftdi cable I can't log my ft's from a trusted source.

I did just order another one a few minutes ago so hopefully that one works correctly

If you are using stock MAF it should be scaled pretty well, don't you think so? Unless someone put his fingers there ;)

Just to clarify, I wasn't suggesting the reasons you were having problems at idle was because of the stock diameter housing, but if you were going to make tuning changes why not start with the larger housing.

Haha that's my logic too, but just wanted to check.  Maybe my tvub values are wrong for the idle voltage

All the big turbo cars I've seen have a 3" diameter housing, and that's with smaller turbos than you have (I think). It's also my understanding that changing TVUB values make the most difference @ idle.

I'm pretty sure my inlet size is 3.5in, but what does that change?  Just asking

You shouldn't adjust TVUB values to compensate. Set them once according to injector specs and tune fueling through FKKVS.

Doesn't matter which MAF you use to dial in fueling, as long as you upgrade it after to not peg the MAF voltage.

IMHO it is easier to dial in injectors and then in second step MAF then dialing everything in one step as you can face issues and you will not know if it is because of imperfect injectors scaling or MAF scaling.

The injector data sheet for the 870s that's floating around had been called incorrect by some people.  And also they're rated at 3 bar and Audi's stock are 4.  I scaled these values by the difference percentage between the 2 pressures.  Is this correct?  And I'll try and find the datasheet for you guys to look at

You should check your fuel trims after dialing injectors to fine tune them!

OP stated this in the first post " I have the stock maf and housing attached ". I suggested rather than change anything file-wise at this point it might be good to start with a housing you know you won't peg. If he makes adjustments now using the stock housing won't he have to re-adjust everything again if he decides he needs to move up to a larger housing even at idle?

I'm at work right now and its raining, but I think I may have figured the problem partially. 

My car came with a narrowband ecu, but I swapped it for a wideband from the next year.  When I was looking up mass airs today they have the atw (narrowband) maf and they have the awm (wideband) maf listed with different part numbers.

In the swap threads I've seen no one has mentioned the mafs being different sensors.  Anyone know if they're physically different?  They both look to be bosch sensors. 

I guess I should find the stock maps and copy them into my current file. 

What's the suggested setup for a 400 awhp car?  V8 maf housing?  I think I can go to the local junkyard and pick up the maf housing and sensor for like $25.  Then it would just be a matter of copying the values from a v8 file right?

Also earlier this morning I was playing around with the different injector settings, and I could not get a good idle to save my life haha. 

No.

http://s4wiki.com/wiki/Fuel_injectors#Flow_dependency_on_pressure

What are your krkte & temin value?

Krkte= .4

Temin= .9 I think

I've tried adjusting these values but it seems the happiest with these.

Looks like your krkte is off try .04000
& temin @ .501 as base.

Since you have large injectors dial down krkte a little bit at a time.

Oops your right it is .04, typed it wrong. 

And what is the difference between temin and teminva?  Should they both be the same?

While I had the maf plugged in today I kept trying to adjust my krkte but it only seemed to change how much fuel was given when I hit the pedal, but steady holding the pedal resulted in richer than 10 afrs. 

I've also set both timing maps equal to try and get rid of the vvt timing error but I continue to get it.  Stuck on this as well

I have a 2.7 & teminva is zeroed out. Have you tried switching back to stock timing maps.
Also read
http://s4wiki.com/wiki/Tuning

maybe the injector on time is so low on the 830cc that they just arent pumping out enough fuel? hows your vaccuum at idle? is it around 20 inches of vacuum?  which injectors exactly are you running? what FPR are you running? any more relavent information you could provide would help. what are your injector on times at idle? whats it like as you drive? can we see some logs also?

Deka 870cc at 3bar injectors (ev1), stock maf, t04e turbo, stock 4 bar fpr, stock fuel pump, 3 in intercooler and piping, forge splitter valve on intake side, map sensor in intake tube.

On Apr tune I pulled about 21-22 in at idle, now its at about 19 and sometimes I have a hanging idle at about 1000-1100 rpm.

I only have an mpps clone cable, and am waiting on another ftdi cable that will hopefully work.  I can log some things with the torque app on my phone.

Yesterday I was looking at the stfts on my phone and every where except idle and cruising it was pulling about 6% fuel.  But was idling lean again.  Unless idle trims are controlled be something else I don't understand what's happening.  This was with the maf unplugged because its my daily driver.

I am asking again how are you going to properly dial MAF and injectors at once? When dialing injectors you are (maybe silently but still) taking MAF reading for granted (so you use fuel trims). When dialing MAF you are depending on properly dialed in injectors so you can use your fuel trims to dial MAF in... When trying to dial both MAF and injectors at once what are you going to use? Trying to dial the injectors with disconnected MAF is also not the wisest idea!

judging b your vacuum numbers you said you have a small vaccuum leak. the high idle is evident of that plus the gauge. if youre near northern california i can help you lock it down. if not just gotta find where it is.

Yes I did.  Fixed that and now it pulls normal vacuum at idle.  Also changed some injector settings and now have a pretty normal idle.

Problem now is my ltft's are getting turned off because of a cam over retarded error.  I've turned off the vvt in the eskonf and have set both timing maps for both the timing variables equal but from there on I'm lost on what to change.  The threads I've seen discussing this never seem to come to a head.

Does anyone know the complete list of variables that need to be changed to completly code out CVT?