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Old 04-25-2005, 12:06 PM   #1
MMBOOST
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Default My Stg 4 is always rich in CLF mode

[I incorrectly posted this first in the EJ20 forum]

I have a TXS-ish Stage 4. Since the first day I've ever captured a log from my UTEC in July 2004, now that I have gone back and checked all my old logs, when my car is in the UTEC's 0% column (i.e. closed loop fuel mode, under 30% TPS), my AFRs average to around 13.8:1. To date, I have not been able to figure out why. All of my modifications involved in this are: TXS UTEC running 4.2c, with a TXS Tuner (VW), recently tuned by PDX. VF34, Vishnu IC hoses, STi pinks, Helix up and down pipes, Borla hush, Helix catch can

Things I have checked so far:

Fuel pressure: deemd fine by LIC Motorsports, ~40PSI
O2 sensors: Both the TXS Tuner w/ VW WB 02 and the OEM front O2 sensors agree on the 13.8:1 AFRs. If both were bad sensors, that'd be quite a coincidence.
MAF sensor: Borrowed a friends MAF and went for a ride. 13.8:1. Reset the ECU and went for another ride, 13.8:1.
IC Hoses: fine, except I had some oil vapors on the bottom of the stock TMIC near the outlet to the throttlebody. Cleaned it up, put the stock hose back in because the Vishnu was in bad shape. As could be expected when fixing a boost leak, my AFRs went up a bit all around, about 0.2... except in the 0% column.
Various boost and vacuum hoses off the intake manifold: Brake assist hose looks fine. Line to MAP sensor (that's the thing readoff the nipple infront of the throttle body, right?) looks fine and its T off to my boost meter seems fine. BOV read line looks good. FPR read line looks good.

Todo: I haven't taken apart the web of hoses near what I'm thinking the MAP sensor is. There' that black disc-ish thing with one hose to its own nipple in the manifold, and another to the intake and another to somewhere I haven't traced yet. I also need to replace the gasket for my BOV - it has seen lots of action, as I used to have an aftermarket BOV, but no longer.

I haven't check my fuel trims because I do not have a device with which I can do that. I'm guess, what they are is not to important as I can see they are off by how how bad CLF mode is performaing. I figure that they are way off, since I am not hitting 14.7:1 in CLF. What I fear is that they are actually already at -25% and can correct no more.

Also, The AFRs I am quoting are from extensive logging, and from using my log combing software at http:// www.logmapper.com. These averages are from non-anomolous, continuous CLF mode readings. I do hit low 14s now and again for a few seconds, but I rarely hit stoich or higher unless they are part of the anomolous transitional AFRs (between on and off throttle or between CLF and OLF).

And ideas, suggestions, advice, etc, in solving this would be greatly appreciated.

jason
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Old 04-25-2005, 01:43 PM   #2
hippy
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What's the 0% column like in your fuel map like? What is the fueling scaling like in your olf parameters?
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Old 04-25-2005, 01:48 PM   #3
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I had the same problem on a car I tuned a few weeks ago. I started dialing in the idle A/F and got it to ~ 14.5:1. 2 days later the car threw a lean code and I put the injector scaling back to stock. Sorry I can't help just thought you woud like to know that it is not only you experiecing this. I have not had the car back to try and figure out what is wrong.

TMS
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Old 04-25-2005, 01:56 PM   #4
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Yeh, I forgot to say that if you want to fiddle with it a bit without getting something to check your fuel trims, it would be pretty easy seeing as you know the a/f ratio. All ya gotta do is raise the stock scaling number in the olf parameters a bit at a time(maybe 20 points at a time) and see what happens. This shouldn't change the hard throttle fueling.

peace
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Old 04-25-2005, 02:58 PM   #5
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Default

I have run anywhere from around -1.5 to around -6.0. Looking back when I was running -1.5 to -2.0 I was seeing AFRs like 13.6:1. Looking at a log of my latest settings of -6.0 is where I see 13.8:1. That's a small enough change to be the delta effect between morning and evening ambient temps... so either way, its around the same low AFR.

I never even thought of messing with the scaling. Here are my params:

[550] [420]

which I believe means I am set to stock as 420 and the STi pinks are scaled to 550. Are you recommending I nudge the stock to 440? Why would you nudge the old (stock) injector value and not the new injector value instead? I'm not sure I am understanding the play between the new and old settings in injectors scaling. It seems raising the new and lowering the old would give the same effect? And visa versa?


The lingering question then is, "Why me?". If I understand what you are getting at, why are my STi pinks magically flowing more than other STi pinks?

jason
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Old 04-25-2005, 03:12 PM   #6
MMBOOST
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Default

Quote:
Originally Posted by TheMadScientist
I had the same problem on a car I tuned a few weeks ago. I started dialing in the idle A/F and got it to ~ 14.5:1. 2 days later the car threw a lean code and I put the injector scaling back to stock. Sorry I can't help just thought you woud like to know that it is not only you experiecing this. I have not had the car back to try and figure out what is wrong.

TMS
Hmmm, so you've already tried what hippy's suggesting? Thanks for letting me know and please keep me informed if you figure out anything else.

thanks,

jason
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Old 04-25-2005, 03:20 PM   #7
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I was thinkin backwards sorry. Ya want to lower the stock scale not raise it(like put it to 400, 380 or whatever). This would be the same as removing maf voltage in your 0% column. The split between the stock and the new injector scale is what makes the utec pull maf voltage at part throttle. The bigger the gap, the more maf voltage the utec will pull. So lowering the stock(while leaving the new injector scaling alone) will pull more maf voltage at part throttle. The new injector scale is what the utec uses for hard throttle adjustment. If you change that, it will change the amount of maf adjustment at hard throttle(higher values being removing more voltage and lower being removing less)........

I dunno why your injectors seem to be flowing more then others. Could be an intake leak somewhere, or certain mods(none that you listed.....). Does the a/f ratio change between when you're at negative pressure more then at small amounts of positive pressure(all at part throttle)? If the answer is yes, I would think it probably has something to do with an intake leak.

peace
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Old 04-25-2005, 04:44 PM   #8
MMBOOST
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The only thing modified on my intake is I cut the resonator "bulb" off and sealed the hole, so that the rest of it is still in place.

Also it sounds like, from TMS's post, that the ECU figures out what you're trying to do and bits you in the butt.

jason
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Old 04-25-2005, 05:11 PM   #9
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Quote:
Originally Posted by hippy
I was thinkin backwards sorry. Ya want to lower the stock scale not raise it(like put it to 400, 380 or whatever). This would be the same as removing maf voltage in your 0% column. The split between the stock and the new injector scale is what makes the utec pull maf voltage at part throttle. The bigger the gap, the more maf voltage the utec will pull. So lowering the stock(while leaving the new injector scaling alone) will pull more maf voltage at part throttle. The new injector scale is what the utec uses for hard throttle adjustment. If you change that, it will change the amount of maf adjustment at hard throttle(higher values being removing more voltage and lower being removing less)........

I dunno why your injectors seem to be flowing more then others. Could be an intake leak somewhere, or certain mods(none that you listed.....). Does the a/f ratio change between when you're at negative pressure more then at small amounts of positive pressure(all at part throttle)? If the answer is yes, I would think it probably has something to do with an intake leak.

peace

This happened on a car with STOCK injectors and turbo. I had both at 440 and it would idle ~13.7:1. I ended up with 440 and 365 and then it would idle ~14.3:1. EGT's were ~1100F with those settings. The car seemd to be fine I did not have a WBO2 on it so I was only reading A/F with the stock sensor using the Utec and my OBD2 software. About 2 days latter it threw the lean code, I forget the #'s. I want to get a WBO2 on it to check that it is reading right. If it is I have no Idea what to do. Maybe reflash back to an earilier fimware in the Utec?

TMS
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Old 04-25-2005, 05:20 PM   #10
MMBOOST
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Default

OK, when I get home tonight I'm going to mess w/ the scaling and see how it goes. Can I change parameters on the fly, while the car is running - that is sitting idle in the garage just change the params and watch the Tuner readout?

For a close to 0% ST trim, what sort of AFRs at warm idle (750rpm) should I be looking for?

jason
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Old 04-25-2005, 05:27 PM   #11
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14.7:1 +/-.2 or .3

You have to save every change for them to take effect. It would be much easier with something to read the ST + LT fuel trims. I got that one cars trims to ~-6% to -9%ST and 0-1%LT and it still threw a code.

TMS
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Old 04-25-2005, 10:55 PM   #12
MMBOOST
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Default

So I played with the Stock Injector Flow setting. From 420, I turned it up to 440. I turned it down to 365. And from some preliminary tests, and it seems to have had NO effect!

This doesn't sound good... sounds like my UTEC might be bad.

jason
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