NefMoto > Technical > Tuning > Big turbo lean idle
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Author Topic: Big turbo lean idle  (Read 20039 times)
catbed
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« Reply #15 on: June 11, 2014, 12:36:43 PM »
Quote from: vwaudiguy on June 11, 2014, 10:35:15 AM
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.

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.
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tjwasiak
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« Reply #16 on: June 11, 2014, 04:39:29 PM »
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.
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Mythbuster74
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« Reply #17 on: June 11, 2014, 05:27:32 PM »
Quote from: catbed on June 11, 2014, 12:36:43 PM
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.
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
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tjwasiak
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« Reply #18 on: June 11, 2014, 06:30:59 PM »
You should check your fuel trims after dialing injectors to fine tune them!
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vwaudiguy
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« Reply #19 on: June 12, 2014, 09:10:15 AM »
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?
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Mythbuster74
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« Reply #20 on: June 12, 2014, 02:04:29 PM »
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?
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Mythbuster74
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« Reply #21 on: June 12, 2014, 02:07:14 PM »
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. 
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nyet
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« Reply #22 on: June 12, 2014, 03:17:54 PM »
Quote from: Mythbuster74 on June 11, 2014, 05:27:32 PM
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?

No.

http://s4wiki.com/wiki/Fuel_injectors#Flow_dependency_on_pressure
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Phasayaseng
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« Reply #23 on: June 12, 2014, 03:51:54 PM »
Quote from: Mythbuster74 on June 12, 2014, 02:07:14 PM
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. 

What are your krkte & temin value?
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Mythbuster74
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« Reply #24 on: June 12, 2014, 04:50:36 PM »
Quote from: Phasayaseng on June 12, 2014, 03:51:54 PM
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.
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Phasayaseng
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« Reply #25 on: June 12, 2014, 06:10:03 PM »
Quote from: Mythbuster74 on June 12, 2014, 04:50:36 PM
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.
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2000 Audi S4 6spd
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Mythbuster74
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« Reply #26 on: June 12, 2014, 06:17:33 PM »
Quote from: Phasayaseng on June 12, 2014, 06:10:03 PM
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
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Phasayaseng
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« Reply #27 on: June 12, 2014, 06:42:50 PM »
Quote from: Mythbuster74 on June 12, 2014, 06:17:33 PM
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
« Last Edit: June 12, 2014, 06:55:39 PM by Phasayaseng » Logged
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TurboNick
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« Reply #28 on: June 12, 2014, 11:30:55 PM »
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?
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Mythbuster74
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« Reply #29 on: June 13, 2014, 05:15:42 AM »
Quote from: TurboNick on June 12, 2014, 11:30:55 PM
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.
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