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View Full Version : Should my LTFT be this high?



Trader
02-20-2009, 12:47 PM
My long term fuel trims are the following:

idle = 4 to 6
Part throttle = 7.0
Engine breaking = 7.8
Medium throttle & WOT = 10.2

My only mods right now are the MSCAI2 with straighteners.

I have checked all the typical areas for leaks. I tightened up all the intercooler piping and intake piping couplers.

The car does not seem any faster with the intake.

Sport6
02-20-2009, 01:05 PM
Hmmm my LTFTs are way different with the "old" mscai...

idle: -7
part throttle: -3
engine braking:-6
medium-wot: 0-1.6

on the way home ill make sure i have those numbers right

bova80
02-20-2009, 01:38 PM
a good range to be within is +/-8%. The ecu won't throw a CEL unless you are +/-20% though.

Trader
02-20-2009, 02:55 PM
What is typical for a stock MS3 with just a CAI?

pwrful4
02-20-2009, 04:55 PM
Did you disconnect the battery during the install?

Trader
02-20-2009, 05:04 PM
No but the ECU has readjusted. These LTFT are after about 100 miles.

CWPspeed3
02-20-2009, 05:07 PM
I get similar numbers with my cobb sri after having it on since June. Hasnt caused any problems yet.

Trader
02-20-2009, 05:11 PM
Yea I have read some people getting higher numbers, but there really is not a lot of response for what is typical or what should they be at. They just seem a little high for just an intake. I am going to check the air straighteners to make sure they are oriented properly.

Could people that have just a CAI or SRI post their LTFT.\

Thanks

bscott2275
02-20-2009, 09:14 PM
cobb sri

idle 3.6
part throttle 7.8 to 8.6
wot 12.6

pretty sure those are the numbers

Silver Ecstasy
02-20-2009, 09:21 PM
I think a lot of this could vary based on temperature too, especially considering we're posting from different climates right now.

Sport6
02-20-2009, 09:23 PM
Yah my estimate was way off

its: MSCAI with the straightener
-3.1 idle
0 for light throttle
3.1 for WOT

I only travel about 3 miles home from work so maybe it wasn't 100% warmed up but I'll let you know if it changes on a longer trip

Silver Ecstasy
02-20-2009, 09:26 PM
MSCAI v2.0

Idle: 7.8
Light to WOT: 3.9

Atleast 200-300 miles on the car since ECU was reset, and I did not baby the car whatsoever after I reset.

mazdaspeedster3
02-20-2009, 09:43 PM
That doesnt seem to bad Mike! I am hoping to get my MSCAI on Tuesday morning first thing! Should be an easy install having done it several times and all I am doing is taking out my Injen. :-)

frito
02-21-2009, 07:59 AM
From the Cobb site.
"- One of the most important things you will want to do after you install a properly designed aftermarket intake system is to reset the ECU and drive at very light loads for extended periods of time after the installation. Resetting the ECU will erase any STFT and LTFT values which will allow the ECU to start
making compensatory corrections to the fueling calculations."

Sport6
02-21-2009, 10:51 AM
Hmm maybe that why are lower than most? I babied it after the install cept for a few runs.

mrmazdaspeed3
08-01-2009, 05:09 PM
how do you check these ltft is there a device i need or what? srry im a noob.

mazdaspeedster3
08-01-2009, 05:22 PM
A dash hawk tells you all of these perameters.

bykeryder4life
08-02-2009, 09:43 PM
guys you gotta take alot of things into account when dealing with fuel trims. where you live, things like elevation, temp, and any mods done will affect them. with the original style MS CAI(i dont know about the V2), the maf housing is larger than stock so this makes the cars run lean, particularly at idle. with the air straighteners they settle down a little bit. With the Standback I can just scale my maf voltage and adjust my trims where necessary with the maf x-fer.