A/F at idle is WAY lean

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Aug 3, 2008 | 01:08 PM

jmtx86

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From: NY

A/F at idle is WAY lean

I just bought the car and at idle the car is WAY lean, Right now im just running a stock map with the injector size bumped. I haven't change the injector battery voltage latency. Is that maybe my problem?

I have precision 850cc installed in the car at the moment with hks 280's. When ever I give the car a little rev and the rpm drop after, the car just dies on me.

Can someone offer me a little help?

Aug 3, 2008 | 04:18 PM

tephra

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what are your fuel trims saying?

Aug 3, 2008 | 04:42 PM

jmtx86

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im going to buy logging software tomorrow, im just trying to get it right tonight, but i guess im going to have to wait it out.

Aug 4, 2008 | 07:35 AM

justboosted02

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search the forum for injector scaling, there are some good instructions on how to do it. just using the scaling number is not enough

Aug 4, 2008 | 12:08 PM

G20

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how did you know it's too lean?

Aug 4, 2008 | 12:13 PM

srcevo8

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From: Orange County, CA

If you give it some gas before the car dies, can you keep the car running? Or does it really want to die at that point and is unrecoverable? If you can save it then it sounds fairly normal for cams.

Sep 20, 2008 | 06:32 AM

jmtx86

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Quote:

Originally Posted by G20

how did you know it's too lean?

AEM WB

Quote:

Originally Posted by srcevo8

If you give it some gas before the car dies, can you keep the car running? Or does it really want to die at that point and is unrecoverable? If you can save it then it sounds fairly normal for cams.

I can save it but it wants to die, I have HKS 280 so that might be it.

Also when I drive the car and give it 25% throttle it leans way out and the car sputters and I have the map extremely rich. Im going to TRY to scale the injectors today and see what happens.

Last edited by jmtx86; Sep 20, 2008 at 06:35 AM.

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Sep 20, 2008 | 09:40 AM

RazorLab

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If the car has larger injectors and the latency table isn't tuned for them, that is your issue.

I am sure the fuel trims are all out of wack.

Sep 20, 2008 | 07:03 PM

Jack_of_Trades

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From: Opelika,AL

Lemme guess, you have 850cc injectors and scaled them with a value of 850 right? Try a value of 780cc and that should get you more in the ballpark for the moment.

Sep 20, 2008 | 11:13 PM

#10

jmtx86

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From: NY

Nope I have them scale lower then that. I need someone to tune my car i think

Sep 21, 2008 | 12:26 AM

#11

tephra

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what are your fuel trims telling you?

Sep 21, 2008 | 09:25 AM

#12

jmtx86

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I have fuel trim Low, Middle, High. Which should I be looking at? I got the car to Idle better but my AF goes from like 14.7-15.1-16.0- then Back up, HKS 280's causing this?

This is the first car im tuning, I just want to get it so I can have some fun (wot runs) and not have to worry about blowing it up until I can get to my tuner.

Sep 21, 2008 | 04:15 PM

#13

tephra

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add these to your evoscan data.xml (near the current fuel trims will do)

Code:

        <DataListItem DataLog="N" Color="" Display="Fuel Trim Idle" LogReference="FuelTrim_Idle" RequestID="0C" Eval="(0.1961*x)-25" Unit="%" MetricEval="" MetricUnit="" ResponseBytes="1" GaugeMin="-255" GaugeMax="255" ChartMin="-255" ChartMax="255" ScalingFactor="1" Notes="" Priority="1" Visible="False" />
        <DataListItem DataLog="N" Color="" Display="Fuel Trim Cruise" LogReference="FuelTrim_Cruise" RequestID="0D" Eval="(0.1961*x)-25" MetricEval="" MetricUnit="" Unit="%" ResponseBytes="1" GaugeMin="-255" GaugeMax="255" ChartMin="-255" ChartMax="255" ScalingFactor="1" Notes="Measured voltage from the car battery. May be as low as 10 Volts when ignition is off. Should rise to around 14-15 Volts when the engine is running." Priority="1" Visible="False" />

Then you can log Idle+Cruise...

Sep 21, 2008 | 05:14 PM

#14

mnbvcxz

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From: Long Beach

im having the same problems!!!i cant figure it out. did a boost leak test, checked for exhaust leaks, switched front o2 sensors. car drives fine. but the idle sucks! it throws the p0300 code every single time at idle. a/f goes from 14.7 and drops to 18.0.