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Old 10-01-2002, 01:19 AM   #1
davidm_sh
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Member#: 5994
Join Date: Apr 2001
Location: Fort Collins, CO
Vehicle:
2004 Impreza WRX STi
Java Black

Default Got the Utec: Think I need some help tuning it.

Ok-

Got the UTEC today and installed it tonight. VERY straight forward install btw. Except for one tiny little thing. The ground cable that comes with it suggests connecting it to the passenger seat bolt but it's WAY TOO SMALL to get it around that bolt thread for the seat? SO I just put the ground on the lower nut/stud of the ECU harness plate (the plate with two nuts that hold it down to the car). Maybe I have a bad ground?

Let me start with my setup:
-VF22
-AEM CAI
-STi injectors + GSS342 fuel pump
-MRT 3" catless turbo back
-perrin catless uppipe
-lightened pullies
-Blitz DSBC for boost
-gauges (EGT, 2 boost, narrow and wideband A/F, knocklink).

ANyway onto the initial review I guess. First off put it in the car and fired it up (starts MUCH quicker than the Link did... nice). But after doing a initial WOT run with it it was off the scale rich (pegged my FJO wideband to 10:1 and was stuttering bad = oops had the switch set to "0" so the stock ECU was doing the best it could with the STi injectors = not so good [heh]). After I pulled into a parking lot I proceeded to get CEL P1507 = malfunctioning idle system. Reset the ECU and switched to Map1 and all was better. Now Phil included two maps for me:

1) STG4+TMIC 17psi
2) STG4+TMIC+Injen Intake (agressive map 18psi)

First odd thing I noticed was that the 0% column (closed loop fuel map) had a difference between the two maps. Map 1 had a -5.5% correction value and Map 2 had a -7% correction value. Accordingly in the idle range of 0% column map 1 was around -6.x% and Map 2 was around -5.5%.

With idle fuel range in the -6 to -7% range my STFT values per my OBDII palm pilot were showing +20-25% correction. With these values I was also getting an idle around 15-16:1. Then I tried adjusting the idle fuel to bring the STFTrim down close to 0% and my A/F went to high 14's:1 range but the value that got it there in the UTEC map was about -2% which seems AWFULLY low correction to me.

Now onto the most annoying things... maybe I am just too used to the Link's static timing/fueling ways. But I don't remember my unichip tune being this jerky in vacuum/off boost driving. I thought the jerkiness was caused by the "dynamic timing" of the stock ECU but after watching my wideband it's CLEARLY the A/F that's causing it. I mean it's fluctuating SO fast that my narrow band A/F gauge is practically all lit up all the time. And my wideband is flying between high 13:1 and high 14:1 A/F's when cruising under very light throttle = bad stuttering of car. Almost bucking when I drive in 1st gear very slowly. I have tried correction values in the 0% column from -2%, -5%, and -7% (the last two were what were in the two maps Phil sent to me) and they all yielded about the same results.

So am I doing somthing wrong? Is this normal? From what I remember on my unichip tune the A/F would stay almost RIGHT at 14.7:1 on my wideband (for the short time I had the two things in my car) and the unichip was MUCH smoother.

Well that is all for now. I am sure most of these "details" are just due to my being new to tuning this ECU so any and all help would be greatly appreciated.

Thanks
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Old 10-01-2002, 01:55 AM   #2
ScoobieSnaX
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David,

Couple of things....

1. Can you send me your Injen map? Thanks!

2. You said you were chaning the idle fuel when you were at ~16:1. Why is that? I could only dream of the day my car would idle (smoothly) at even 15:1 with the Link. I'm thinking the fuel trim values you're reading might not be "adjusted values" which the UTEC is sending.....just a guess.

I remember changing fuel during idle with the Link and having it run WAY lean or on the rich side of things (14:1). It was tempermental at best...

My car drives quite well at part throttle, low boost, and vacuum. If I could get my damn laptop to stop locking up Hyperterminal I might be able to compare some data which brings me to my next point.

Either post, or send me your datalog....just curious if nothing else. My injector duty cycle was all over the map (no pun intended) and showed values of 1079!! odd!!
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Old 10-01-2002, 02:04 AM   #3
davidm_sh
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2004 Impreza WRX STi
Java Black

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Quote:
Originally posted by ScoobieSnaX
David,

Couple of things....

1. Can you send me your Injen map? Thanks!

2. You said you were chaning the idle fuel when you were at ~16:1. Why is that? I could only dream of the day my car would idle (smoothly) at even 15:1 with the Link. I'm thinking the fuel trim values you're reading might not be "adjusted values" which the UTEC is sending.....just a guess.

I remember changing fuel during idle with the Link and having it run WAY lean or on the rich side of things (14:1). It was tempermental at best...

My car drives quite well at part throttle, low boost, and vacuum. If I could get my damn laptop to stop locking up Hyperterminal I might be able to compare some data which brings me to my next point.

Either post, or send me your datalog....just curious if nothing else. My injector duty cycle was all over the map (no pun intended) and showed values of 1079!! odd!!
1) Sure... as soon as I download it too my laptop and then to my main machine.

2) I wanted to get the idle as close to what the stock ECU wants as possible via the stftrim values... but you maybe right in that I maybe reading a "false" reading through the OBDII port as I don't know if that is pre/post/whatever UTEC data.

I haven't datalogged yet... I was just driving looking at the dashboard and my gauges getting a feel for how the car was behaving.
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Old 10-01-2002, 04:54 AM   #4
davidm_sh
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2004 Impreza WRX STi
Java Black

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Well I put the UTEC ground wire to a different spot with no affects noticable so I think my first grounding point was good.

I went up to about -9% in column 0% for closed loop and the A/F's shifted from high 13's-14.7:1 to mid 14's to low 15's:1. It helped out a little bit. Did a little more WOT tuning. Just for reference when my boost gauge reads about 3-4psi that equals 0psi on the map sensor. I am getting some fairly serious hesitation around 0psi-4psi (boost gauge) so probably about -2 to -3psi UTEC sea-level scale.

Once I go TPS = 100% things seem to smooth out considerably and the A/F stabilizes as well. I need to lean things out a bit more but it's getting there. WOT stuff is EASY to tune... I just don't really have much idea about closed loop since I don't really have that much control there .
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Old 10-01-2002, 09:20 AM   #5
nmyeti
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Location: Albuquerque, NM USA
Default

David,
A few things here...

1. You need to make sure that your 0% zone is tuned to help the ECU learn how closed loop control should be. In the end though, because we are letting the ECU help control some of that zone, you need to help the car by letting it learn just a bit.


2. Your "-2" in the idle zone is likely related to your AEM intake with its larger than stock mass air sensor housing.

3. If you have questions call...
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Old 10-01-2002, 11:31 AM   #6
RiftsWRX
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Location: Glendale Hts, IL, USA
Vehicle:
2000 NFR AP1 S2000
'07 Honda FIT sport (5MT)

Default

Ditto on what nathan said.. that initial +25% is probobly from the LFT that was learned PRIOR to the UTEC installation.

If in doubt.. set the 0% map where it was originally, reset the ecu, and check SFT again in about 3 or 4 trip cycles and report back.

The other thing... for your 0-4PSI hesitation, look at the parameters map and look in special constants and make sure your TPS crossover % is set right (55%-65% typically) and not at 0%

Jorge (RiftsWRX)
www.ProjectWRX.com
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