Mythbuster74
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« on: June 11, 2014, 06:47:38 AM »
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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?
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Mythbuster74
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« Reply #1 on: June 11, 2014, 07:03:37 AM »
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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.
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julex
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« Reply #2 on: June 11, 2014, 08:02:41 AM »
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What ecu is it?
Do you reach learning limits on fuel trims?
as far as OBD... Ross-tech cable can't be beat.
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Mythbuster74
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« Reply #3 on: June 11, 2014, 08:16:50 AM »
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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? |
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vwaudiguy
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« Reply #4 on: June 11, 2014, 08:34:25 AM »
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Don't big turbo (you never said which, but based on your injectors..) setups need a larger maf housing?
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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Mythbuster74
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« Reply #5 on: June 11, 2014, 08:39:08 AM »
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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. |
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Mythbuster74
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« Reply #6 on: June 11, 2014, 08:42:20 AM »
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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
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tjwasiak
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« Reply #7 on: June 11, 2014, 08:42:39 AM »
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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...
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Mythbuster74
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« Reply #8 on: June 11, 2014, 08:47:28 AM »
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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. |
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Mythbuster74
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« Reply #9 on: June 11, 2014, 08:48:23 AM »
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I did just order another one a few minutes ago so hopefully that one works correctly
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tjwasiak
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« Reply #10 on: June 11, 2014, 08:50:00 AM »
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If you are using stock MAF it should be scaled pretty well, don't you think so? Unless someone put his fingers there  |
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vwaudiguy
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« Reply #11 on: June 11, 2014, 10:15:44 AM »
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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.
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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Mythbuster74
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« Reply #12 on: June 11, 2014, 10:25:11 AM »
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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 |
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vwaudiguy
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« Reply #13 on: June 11, 2014, 10:35:15 AM »
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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.
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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Mythbuster74
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« Reply #14 on: June 11, 2014, 12:02:55 PM »
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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 |
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