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Old 02-24-2008, 06:47 PM   #1
simon021
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Member#: 157532
Join Date: Aug 2007
Chapter/Region: MWSOC
Location: Iowa
Vehicle:
2002 MY03 EJ207 E85
Dom 1.5XTR Twinscroll!

Default Wierd AFR Issues. Swinging almost a full point.

2002 WRX Sedan
EVOIII16G
modd'd stock injectors 808, 820, 820, 824
gp moto catless 3" TBE.
helix v3 up pipe
tial 38mm EWG
LC-1
Lightweight flywheel
domtune boost control solenoid

I think thats everything...

Anyways about a month or so ago the hose blew off the passangers side of the intake manifold and i lost fuel pressure and was running lean for a day or so. Got it hooked back up on there and stuck a ziptie around it for good measure. Immediately I noticed I was running ~10:1 instead of my target 11.3:1 or so. sometimes even in the high 9s:1 ratio. pig rich basicly. I figured it was just because that line had been leaking the whole time, causing me to have poor fuel pressure, and we had just been tuning around it the whole time. Either that, or the TGVs were getting sucked closed at high rpms since my sensor was screwed up from the new turbo install. I took some logs for a few days, and then one day all of a sudden I was running right where I should be, right at 11.3:1. It's been doing this for a few weeks now.

I put in new plugs the other day, one step colder NGK Iridiums at the request of my tuner. Also fixed the TGV sensor that we screwed up on the turbo install.

did a compression test and the results were great. I can never remember which cylinder is which so I'll just use front and rear.

Drivers Front - 160
Drivers Rear - 155
Pass Front - 149
Pass Rear - 155
Drivers Front - 155


I still have the same AFR problems, although the car does feel much better with the new plugs. Here are the 2 most recent logs. The rich log was taken 2 days before the lean log. I haven't even opened the hood since then. I haven't touched anything on the car in between these 2 logs.

Here is a link to the romraider forums. I posted this up there because I couldnt get the logs to look readable on these forums. Also i posted my fuel map as well.

http://www.romraider.com/forum/post27658.html#p27658

I realize there is a huge boost spike but I can't imagine that is causing this issue at all. That will be taken care of soon enough, We are just totally stumped on why the AFRs are going crazy like that. Any ideas would be greatly appreciated.
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Old 02-25-2008, 02:09 AM   #2
williaty
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Is there any possibility it was tuned while you had some problem making you run lean? In other words, if the car weren't happy, then you tuned it, then you made it happy, your tune is going to be off.
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Old 02-25-2008, 09:12 AM   #3
simon021
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Quote:
Originally Posted by williaty View Post
Is there any possibility it was tuned while you had some problem making you run lean? In other words, if the car weren't happy, then you tuned it, then you made it happy, your tune is going to be off.
That was my original idea. I figured that hose on the manifold was leaking, causing me to get poor fuel pressure, making it run leaner than it should be and we were tuning around that. Then i got it fixed, and i was pig rich. The only problem is, we didnt change the map at all, or anything under the hood, and it spontaniously started running right on target again, not rich at all. Then a few days later it would be running rich as hell again. now it's been running on target for the last 2 or 3 days, I've been logging a few times a day and it's been looking good. I got a new map today to fix the boost spike, so I'm going to flash that, reset the ECU, and take some more logs and see if that changes anything.
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Old 02-25-2008, 10:10 AM   #4
simon021
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Dom 1.5XTR Twinscroll!

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Ok I think i have it figured out. Correct me if I'm wrong here.

My tuner sent me a new map today to fix the boost issue. I had a hunch that after I reset the ECU i was going to be running pig rich again, because I noticed my AFR learning was almost -7. Sure enough, I flashed the new map, reset the ECU and went to take a log and I'm running high 9s low 10:1. I'm willing to bet it will get leaner incrementally until it's hitting targets again. Which leads me back to my original theory, that the line coming off the manifold that effects fuel pressure was leaking the whole time we were tuning before, and now that it's on there tight, it's running rich.

Is this a plausible situation? AFR learning is in percent right? 7% leaner than ~10:1 is pretty close to 10.7:1 Makes sense right?

The new log is in the linked romraider post.
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Old 02-25-2008, 04:06 PM   #5
Infamous1
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Black/Black

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Check your A/F Learning A,B,C and D in your case after some miles it will most likely show values in the negative % ranges. Simply your car was tuned with low fuel pressure and the injector values are now off after the problem has been fixed.
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