Fuel trims again
06-04-2012, 04:22 PM
#11
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Join Date: Sep 2006
Location: Gainesville, FL
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^ Same. I think it's fine.
My LT trims are usually negative -5 to 15% at idle. The two banks are off from each other at idle by quite a bit, sometimes 8% or more. But they don't dip down under -15%. During cruise both banks are -1 to -5% typically. While accelerating they get closer to zero with the more throttle I input. I have an AEM and the car maintains stoich fine during idle and cruise.
Last year the car tended to run richer long term trims. More like +5-8% during cruise. I pulled the fender and replaced the air filter, part of the intake, and put some RTV on the joint where the passenger side PCV hose hooks into the intake, then reset the tune. Not sure if that is what caused the difference but it definitely has learned new trims now vs. before I did this.
My LT trims are usually negative -5 to 15% at idle. The two banks are off from each other at idle by quite a bit, sometimes 8% or more. But they don't dip down under -15%. During cruise both banks are -1 to -5% typically. While accelerating they get closer to zero with the more throttle I input. I have an AEM and the car maintains stoich fine during idle and cruise.
Last year the car tended to run richer long term trims. More like +5-8% during cruise. I pulled the fender and replaced the air filter, part of the intake, and put some RTV on the joint where the passenger side PCV hose hooks into the intake, then reset the tune. Not sure if that is what caused the difference but it definitely has learned new trims now vs. before I did this.
I'm going to get a brenspeed tune, so it will be interesting to see what the trims read.
06-05-2012, 12:43 AM
#12
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Join Date: Dec 2006
Location: Redding, CA
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Between four kids, a 50 -60 hour per week job, a house that needs maintenance, an ex wife, a girlfriend, coaching baseball, going to baseball, going to family functions and eating/sleeping/crapping, I don't have enough time to investigate my short/long trim fuel trims. I love you guys for knowing though. lol. I just get in my car and go. Put in gas, change the belt and plugs from time to time, oil twice a year. Im good.
I guess it must be my Kenne Bell. The whipple must be an inferior product, J/K.
I guess it must be my Kenne Bell. The whipple must be an inferior product, J/K.
06-05-2012, 06:55 PM
#13
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There's your problem! Kids are a huge waste of time and money. Plus they are annoying.
Either I or my wife are sterile, so I will be retiring early and driving my kids college fund. She's a little disappointed, but not me!
Either I or my wife are sterile, so I will be retiring early and driving my kids college fund. She's a little disappointed, but not me!
06-08-2012, 07:19 PM
#14
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I don't know what I was searching for when I found this post, but it's a quote from evolution performance about the FRPP whipple HO tune.
"10.8 AFR is really rich, I have done several Whipple Installs and based lined them with the FRPP Tune, which flat out sucks.
FRPP are WAY TO Conservative.
Their tune is way too rich, timing is very low, and it pulls timing way to quickly.
The FRPP Tune also leaves the CAT Over Temp Cooling enabled in the tune, which will dump a considerable amount of fuel, once the CATS get hot, which could cost you up to 25-30 RWHP, and make the car feel sluggish.
We custom tune every Whipple Supercharged 05-07 Mustang GT for this reason."
Maybe my fluctuating fuel trims at idle are because of the cat over temp cooling. So the computer adds fuel to cool the cats, never knew that.
"10.8 AFR is really rich, I have done several Whipple Installs and based lined them with the FRPP Tune, which flat out sucks.
FRPP are WAY TO Conservative.
Their tune is way too rich, timing is very low, and it pulls timing way to quickly.
The FRPP Tune also leaves the CAT Over Temp Cooling enabled in the tune, which will dump a considerable amount of fuel, once the CATS get hot, which could cost you up to 25-30 RWHP, and make the car feel sluggish.
We custom tune every Whipple Supercharged 05-07 Mustang GT for this reason."
Maybe my fluctuating fuel trims at idle are because of the cat over temp cooling. So the computer adds fuel to cool the cats, never knew that.
09-04-2012, 04:44 PM
#16
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I got a brenspeed tune and guess what. They don't have long term fuel trims enabled, lol! Short term are there and don't change much at all, even at idle, so I'm guessing the whipple tune is just lean in the idle are of the fuel map.
I also got the wideband and it stays at 14.x regardless of what the fuel trims are showing.
09-04-2012, 05:10 PM
#17
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Location: Gallifrey
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One thing I've been meaning to ask. I've watched mine like a hawk due to the long term issue I've had with higher tunes being lean (pinging).
My LTFT under normal driving is yanking fuel by 13% (-13.something), at WOT when it pings that of course goes to 0, but STFT is still yanking it, and it drops steadily. (-3, then -5, -7, etc..).
Is this showing what it is TRYING to do, or what is actually occurring? My tuner still hasn't been returned to me as it was RMA'd, otherwise I'd try some data-logging, just monitoring trims via basic ELM327 chip ODB-II interface. I'm just feeling like I'm missing something..
This is basically all I'm going on for this:
[youtube]oRX2V6_a3dc[/youtube]
My LTFT under normal driving is yanking fuel by 13% (-13.something), at WOT when it pings that of course goes to 0, but STFT is still yanking it, and it drops steadily. (-3, then -5, -7, etc..).
Is this showing what it is TRYING to do, or what is actually occurring? My tuner still hasn't been returned to me as it was RMA'd, otherwise I'd try some data-logging, just monitoring trims via basic ELM327 chip ODB-II interface. I'm just feeling like I'm missing something..
This is basically all I'm going on for this:
[youtube]oRX2V6_a3dc[/youtube]
Last edited by wayne613; 09-04-2012 at 05:19 PM.
09-05-2012, 06:09 PM
#18
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Join Date: Sep 2006
Location: Gainesville, FL
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One thing I've been meaning to ask. I've watched mine like a hawk due to the long term issue I've had with higher tunes being lean (pinging).
My LTFT under normal driving is yanking fuel by 13% (-13.something), at WOT when it pings that of course goes to 0, but STFT is still yanking it, and it drops steadily. (-3, then -5, -7, etc..).
Is this showing what it is TRYING to do, or what is actually occurring? My tuner still hasn't been returned to me as it was RMA'd, otherwise I'd try some data-logging, just monitoring trims via basic ELM327 chip ODB-II interface. I'm just feeling like I'm missing something..
This is basically all I'm going on for this:
[youtube]oRX2V6_a3dc[/youtube]
My LTFT under normal driving is yanking fuel by 13% (-13.something), at WOT when it pings that of course goes to 0, but STFT is still yanking it, and it drops steadily. (-3, then -5, -7, etc..).
Is this showing what it is TRYING to do, or what is actually occurring? My tuner still hasn't been returned to me as it was RMA'd, otherwise I'd try some data-logging, just monitoring trims via basic ELM327 chip ODB-II interface. I'm just feeling like I'm missing something..
This is basically all I'm going on for this:
[youtube]oRX2V6_a3dc[/youtube]
I reloaded my brenspeed tune after the car was hot, so the fuel trims didn't kick in right away and my AFR was 15.5 or so. That means it takes 17% more fuel at idle to lower that 1 full point to around 14.5? That seems like a lot, but I guess it's 17% more than whatever is in that particular fuel cell. So if it's 100, then it needs 117.
09-05-2012, 09:56 PM
#19
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Join Date: Dec 2010
Location: Gallifrey
Posts: 1,596
That makes a bit more sense then. I honestly didn't know. I've tried to practically memorize what I've been exposed to, but this I was ignorant of. So that STFT on mine dropping at WOT is either a symptom, or simply erroneous(open loop).
Last edited by wayne613; 09-05-2012 at 10:03 PM.
09-06-2012, 07:55 AM
#20
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So if you show .90 for short term at WOT, the commanded air fuel should be .90 x 14.64 = 13.176:1. If you had a wide band sensor, then it should reflect that.
Now I'm not sure if -7 at WOT is .93. I will have to record my stft and let you know what I get. Everything I've read says that short term is adding fuel if it's less than 1 and long term is adding fuel if it's more than 1. My aeroforce gauge converts these to percentage, so I assume a positive number for either lt or st is adding fuel.
just monitoring trims via basic ELM327 chip ODB-II interface
Last edited by moosestang; 09-06-2012 at 07:59 AM.