High AFR Trouble - suggestions?

So after a handful of weird CELs, see below, they've all gone away. Maybe it was the purge valve or something. I also fixed a small leak near my intercooler. So the problem now is that my AFR at idle is about 16, and it idles very rough, like it almost wants to die. The car seems fine driving though.

I checked the resistance of the injectors (huge PITA)
cy. 1 = 13.5
cy. 2 = 13.7
cy. 3 = 13.6
cy. 4 = 13.9


What should I do next? I'm running out of ideas and time. I've been neglecting my homework all day long. Which one of you subie gods could I hire to troubleshoot if I decide to throw in the hat?



mods - turbo back 3" exhaust, catless UP, 660 cc modded injectors, Walbro FP, DB 20G, Perrin turbo inlet, SSAC TMIC, snow meth injection (75% methanol), one step colder copper plugs.












here's the story...I filled up my gas tank and tried to start the car. It was turning over for about 5-10 seconds before it would catch. After it started it was running really rough for a bit, then I got misfire codes (there was two or three different cylinders but I forget which, one was definitely 301). Then I reset the ECU and had no problems.

An hour later, I got CEL 457 EVAP system leak (gas cap). Checked the gas cap and it was tight. Reset ECU and all was fine. Somebody suggested that CEL could be related to the fuel tank seal, though I haven't checked it yet.

A few hours later, I filled up my tank again and had the same problem with engine not catching, then I get CEL 301 again. It goes away, but 546 EGT and 457 EVAP come back.

 

This only happens when the fuel is full, correct? Does it still happen if you stay away from being completely full of fuel?

 

My gas tank is only half full.

 

Sounds like you have another post MAF intake leak, or a bad fuel pump, or even a bad injector.

 

Bad or dirty MAF sensors can also cause misfires. Your evap code, and the EGT shouldn't make your car run crappy, so I would check elsewhere first. Don't worry about those two codes.

 

Other thread was fine. Just had more information and thought you guys would pay more attention to a new thread.

Stock intake. Tuner suggested looking for any leak pre-turbo or post-throttle body and check resistance on injectors. I was running my most current map for a few days with no issues.

I've got Enginuity and don't exactly know how to view fuel trims, but it looks like the range is 14.70-11.54

 

You would need to use the enginuity logger, and view learned fuel trim and corrected fuel trim.

 

Post throttle body leaks would be more unlikely, unless you removed your intake when you did the injectors, and you didn't replace the gaskets.

 

Air/Fuel Learning #1 (%) = 5.47, Air/Fuel Correction #3 (%) = -.78

I used new gaskets when I did the injectors.

 

Those trims don't look bad. I'd maybe check your MAF sensor. If you have any different panel filter in the stock box, it may have been over oiled causing your MAF sensor to get gummed up, and read incorrectly at certain times.

 

I had an OEM filter do the exact same thing to me. Ask Brian how over oiled that filter was. It coated the entire top of my air box. Anywho, MAF cleaner and an ECU reset solved the issues I was having after I originally replaced the filter.

 

ECU was just reset here's a log

Some driving logs
http://andrewcox.org/AC_driving_cel_problems.xls

Idle log

http://andrewcox.org/AC_idle_cel_problems.xls

 

Your fuel trims are all ****ed up in both of those logs, more than likely due to your modded injectors. When not tuned properly, they will also idle like ****.

LTFT is +14% in the first one and your STFT is pegged @ 25% in the second.

 

The car had been running great, up until I filled up at Holiday Sunday morning. I pressure tested the intake system by attaching a pvc cap with valve stem to the turbo inlet, no leaks anywhere.

I was just running the engine at idle and the AFRs were floating around 16. Normally the ECU follows the map and keeps AFR around 14.7

I'll post some updated logs tonight. Maybe the leak near the IC that I fixed made some sort of difference. Since those logs, I've taken apart and reassembled various hoses. Maybe I accidentally fixed something.

 

Who would you guys suggest do the tune in town? I don't have an AP.

 

im gonna tell you right now....not db

 

Updated Log
http://andrewcox.org/AC_highAFR.xls

It seems that high AFRs occur only at idle, see end of log...

 

It's the tune, imho.

You are going lean at idle because the ecu cannot add any more fuel. Your long term fuel trim is maxed out at 25% -- this should throw a CEL (if it hasn't been disabled).

The other areas where you are getting afrs of 20:1 are normal from what I can tell -- it looks like you let off the gas while coasting & engine braking. The injectors will momentarily shut off during this process.

 

What kind of car is this?

 

That's normal for modded injectors. Can you post your map or send it to me?

 

2005 WRX - latest map http://andrewcox.org/Alki05WRX20Grev12b.hex

Here are some other logs from a few days ago. I guess the high AFRs have been an issue since I first loaded this map. I guess I didn't notice it then.

3rd WOT
http://andrewcox.org/AC_rev12b_3rdWOT.xls

driving
http://andrewcox.org/AC_rev12b_driving.xls

 

You injector latency values have been raised a bit. It looks like your tuner was attempting to compensate for the nonlinearity of modded injectors by changing that. Obviously it didn't work.

 

I switched back to another map that originally produced logs with AFRs nearly pegged at 14.70 The car is still idling at around 16.0 Wouldn't that definitely suggest that something mechanically has changed?

 

Maybe, but its more likely still something wrong with the tune. The only thing that would mess up your idle fuel trim that much is a drastic fuel pressure change, but I've never seens that happen.

 

I can't argue against a bad tune as I'm no expert, but how could a map give good AFRs one week and 16s another, without any change to the tune?

 

updated map, i'll run it tonight and post new logs

http://andrewcox.or/Alki05WRX20Grev13.hex

 

My lc-1 is screwy right now. I'm going to try recalibrating it. I went to Holiday on the way home to buy some Octane boost, maybe to clean out the system and potentially bad gas. The guy at the counter said, "Oh, you got bad gas huh, well Holiday gas is the best." I told where I suspiciously got the bad gas.

 

When is your meth injection set to turn on and off? I don't know how those things work.

 

~3.7 volts MAF - max voltage

I really don't think it's the tune, as the car was running great before. I made no changes and it started idling funny. I even switched back to a conservative map that produced good logs with good AFRs and the car still ran funny. This all started after filled up at Holiday on University. Could it be bad gas?

 

found an exhaust leak at the midpipe-downpipe joint. the section is about an inch down from the stock O2 sensor. would that cause the AFR readings to be high? i'm going to get it welded in the morning.

 

it could be

 

i think only pre-turbo will cause afr issues, not after

 

well the leak is about 2 inches downstream of the o2 sensor. maybe, at idle the small leak is under vacuum, air is sucked in, voila...high afrs? i'll know after i get it welded shut tomorrow morning. i was just hoping somebody would say, "yup, you solved your problem."

 

dang.

 

ditto.

 

as the tuner of this car, I just want to point out a few things.

Andrew is running the factory intake. Therefore drastic change of the MAF cal shouldn't be necessary. Sometimes, the use of modded injectors can require a small change in the maf cal to make up for the non linear flow, but not something as drastic as what just happened all of a sudden.

His previous logs on older maps did show a learned of about 14% with an instantaneous correction of 0. So there was some adjustment needed to get the trims down low taken care of.

Customers however, want to see improvement. They want results. Making little changes here and there to combat a slightly high learned correction that isn't affecting the way the car runs doesn't achieve what is frequently desired. So I wasn't working on that primarily. My largest focus was getting the fuel and timing correct for the current setup.

Someone said the "timing is ****". I don't believe they realized how the alky kit was triggered.

If you look at the timing advance, you'll see the areas with higher correction are the areas where alcohol is being injected and at its highest concentration for total combustibles. As the fuel percentage gets higher and alcohol percentage gets lower, the timing is backed off again. Fuel map is similar.
In Andrew's case, his injection starts at 3.7volts. Going to his MAF cal will get you the g/sec airflow that correlates to 3.7volts.
g/sec*60/RPM gets you the load site at the specific RPM that alcohol is admitted. Thus, the diagonal trend on the fuel and timing maps.

I added the timing to the timing correction/advance map to give the ecu more authority to pull more timing in the event of a knock event due to an alcohol problem or air bubble. I don't want to raise the base timing too far because then even with a IAM of 6, there might still be too much timing.

As far as Andrew's problem is concerned, I think something happened to the car or he got some bad gas. I had a similar problem at Chevron more than once. I don't use Chevron anymore. Car wouldn't start for 5 minutes or even idle for 10.

"Mail order tunes" aren't bad at all as long as you find someone who is willing to make constant revisions to the tune via logs and communication. I have many many customers who are satisfied with their internet tunes and the low cost. Unfortunately, I have to deal with people who always point the finger at the tune first off. 90% of the time I can troubleshoot the problem via email and the customer will argue with me about it for days. Claiming it's the tune. Then a week later, the problem will be found and I'll get an apology. My favorite was a customer who ran my tune for a month without any problems. Then he cleaned his MAF and the car wouldn't idle smoothly. Told me over and over that my tune was the problem. I told him over and over that his car was stock and I didn't adjust ANYTHING associated with the idle. He finally found his vacuum leak after bitching at me for a month.

 

zing.....


again OP never mentioned alcahol injection or the likes....

 

:???:

 

ha ha maybe he did... was too lazy to look back over the posting... either way... zing from tuner



and I stand corrected... ha ha