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Old 07-25-2018, 10:40 AM   #1
currancchs
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Member#: 488200
Join Date: Jul 2018
Location: Brookline, NH
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2006 WRX TR
World Rally Blue

Default Any reason for OL idle?

Just bought a 2006 WRX with a TD05-20G turbo, Walbro 255lph fuel pump*, Injen CAI, catless downpipe, 3 port bcs, and open source tune. Was doing some data logging with the car idling and noticed that fuel trims (learned values) were all 0. I had pulled the battery a few days ago and had only taken it for a short drive since, but thought it odd that fuel trim A, at least, was not moving. Checked CL/OL status and it never went into CL fueling, despite being warmed up. Looked at my OL fueling tables and the minimum OL enrichment value is 14, but the top-left block (idle) in my OL fueling table is 13.73; all nearby blocks are 14.70. Idle MAF is ~3 g/sec. I believe this is what is keeping my car in OL, but am curious why somebody would intentionally force the car to stay in OL at idle. It idles OK, but could certainly be better! Also, all CL/OL delay tables appear to be zero'd out. Car isn't registered and it was late, so I didn't take it for a drive to see if it went into CL during cruise.

My question is, before I change this odd value to 14.70, is there any reason someone may tune a car to idle in OL? The seller had mentioned that he bumped the idle speed up slightly (still under 1k), but didn't explain further (I know I should have asked for more information...).

Additional information:
-Car has a pending P0030 - Upstream O2 Heater Circuit Malfunction - A replacement upstream O2 sensor has been ordered and I know that this could result in the vehicle staying in OL, but I don't think its the only cause here (might have something to do with the seller not wanting it to idle CL though, maybe the O2 sensor was not reading properly at idle and he changed idle to OL to sell the car?)
-Car, according to upstream O2 sensor, goes VERY lean under sustained boost. At boost onset, the AFR drops to ~11:1, but, after about 1-2 seconds at 16psi, goes rapidly max lean. I suspect MAF, fuel pump, primary O2 sensor, or tune. Monitored MAF readings at idle and saw ~1.4 g/s. Cleaned MAF and saw ~3.0 g/s, so may have already solved my issue there. Haven't datalogged WOT since prior to the MAF cleaning, need to get around to installing wideband and have been a bit busy/lazy, but don't feel safe going WOT until I have a standalone monitor in place so I can back out right away if it starts to go lean. Also tested fuel pressure and its about 44 psi on a turn of the key and about 35 at warm idle. I did clamp the line right after the gauge briefly to measure deadhead pressure, and it maxed out at ~65 psi. Thought it should have been closer to 100psi. Pump is, allegedly, a Walbro 255lph. I will be starting a separate thread for this issue eventually, unless I figure it out myself before I get around to posting, but thought it might be relevant to this (potential) issue.
-Wastegate max duty cycle is lower than wastegate min duty cycle in the tune in some ranges...

Map can be accessed here:
https://www.dropbox.com/s/3wv51519mc...chase.bin?dl=0

Datalog can be accessed here:
https://www.dropbox.com/s/z3ic1dy0md...og41.xlsx?dl=0

P.s. if anybody knows of a modification-friendly inspection station in the Southern NH (Nashua, Hollis, Brookline) area, please PM me!

*Turns out it actually had an OEM Sti fuel pump, which is significantly less powerful than the Walbro 255lph I was told it had. Discovered this when I pulled the pump to check on things.
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Last edited by currancchs; 07-27-2018 at 12:49 PM. Reason: Removed visible <br>, corrected typos, added info
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Old 07-26-2018, 05:52 AM   #2
NSFW
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Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

It's funny to see this thread because my car has a 14.0 cell in the top-right corner, which forces open-loop for idle. I noticed that a couple weeks ago, and I still can't remember why I did that. I can't even remember doing it, and I am the only person who has ever tuned my car.

But I'm pretty sure we'll both be just fine setting that cell to 14.7 like its neighbors. I'm guessing it was just done to troubleshoot a vacuum leak (fuel trims will try to hide it), and wasn't supposed to stay that way.

As for going lean in boost, that could be a serious problem. My guess is a bad fuel pump, but it's just a guess. When my old pump went bad it would go somewhat lean at high RPM and full throttle, like 12:1 (maybe 13:1?) instead of 11:1.

If you have a data log of the leaning out happening, check the MAF values and see whether it is dropping significantly. If it's holding pretty steady then you can rule out MAF as the problem. It might drop a bit at high RPM, but not dramatically. If you plot it, it should look a lot like a horsepower curve.
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Old 07-26-2018, 08:39 AM   #3
contaminatrix
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Join Date: Dec 2015
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Location: Nairobi
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2002 SG5-2.0-XT-JDM
45A, originally 18L

Default

i think i have the same problem as you OP. unfortunately for me, I can't pull my map and I have no cables that can do so. I'm using btSSm to log.

my afr sensor needs to be toyed with to work. one time i'll start the car and it doesn't read. after some tlc and massaging it wakes up and reads (after an ecu reset however).

i think my mapper also put me in permanent open loop. i see idle at ~12.5 - 13.9 during warm up. when i begin to drive it drops to around 11.0, when it's fully warm it idles at 15.2.

during boost, as you can see here, my afr goes lean. granted my intercooler is useless (evidently from my rising intake temp) but it should become richer as air flows.

mods
SD tune
pinks
tbe
cai
255 lph with voltage relay hardwire mod
inline fuel filter
3port bcs
td05-16g hw
sti-size tmic
93 octane
max boost 1.35-1.42 bar




do you consume more at idle than you normally would?
have you also tested the pump's flow rate?
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Old 07-26-2018, 08:42 AM   #4
contaminatrix
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Member#: 435611
Join Date: Dec 2015
Chapter/Region: International
Location: Nairobi
Vehicle:
2002 SG5-2.0-XT-JDM
45A, originally 18L

Default

WOW DUDE!! 20:1 is INSANE!

MAAAAAAAAAAAAYBE the afr isn't working as it should.....?
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Old 07-26-2018, 10:31 AM   #5
currancchs
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Join Date: Jul 2018
Location: Brookline, NH
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2006 WRX TR
World Rally Blue

Default I agree!

Quote:
Originally Posted by contaminatrix View Post
WOW DUDE!! 20:1 is INSANE!

MAAAAAAAAAAAAYBE the afr isn't working as it should.....?
contaminatrix, I agree. Perhaps under high backpressure the O2 sensor is reading incorrectly and the mixture is actually OK? Not sure if this is a failure mode of these sensors, but seems possible to me. Also perhaps relevant is that I have virtually no knock during these apparent lean events, Fine Learning has gone -1.5 on occasion, but dam stays at 1 and Feedback Knock Correction stays at 0. I would think that I'd be knocking like crazy at those values!

In any case, new O2 sensor is on the way and I already have a wideband ready to install, just have to find the time to do it. Might not be until next weekend (going away this weekend), but I'll get to it and report back with fresh logs when I can.
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Old 07-26-2018, 10:45 AM   #6
currancchs
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Member#: 488200
Join Date: Jul 2018
Location: Brookline, NH
Vehicle:
2006 WRX TR
World Rally Blue

Default Thanks!

Quote:
Originally Posted by NSFW View Post
It's funny to see this thread because my car has a 14.0 cell in the top-right corner, which forces open-loop for idle. I noticed that a couple weeks ago, and I still can't remember why I did that. I can't even remember doing it, and I am the only person who has ever tuned my car.

But I'm pretty sure we'll both be just fine setting that cell to 14.7 like its neighbors. I'm guessing it was just done to troubleshoot a vacuum leak (fuel trims will try to hide it), and wasn't supposed to stay that way.

As for going lean in boost, that could be a serious problem. My guess is a bad fuel pump, but it's just a guess. When my old pump went bad it would go somewhat lean at high RPM and full throttle, like 12:1 (maybe 13:1?) instead of 11:1.

If you have a data log of the leaning out happening, check the MAF values and see whether it is dropping significantly. If it's holding pretty steady then you can rule out MAF as the problem. It might drop a bit at high RPM, but not dramatically. If you plot it, it should look a lot like a horsepower curve.
Hi NSFW, thanks for reading/commenting, I really appreciate it. That's pretty funny re: your open loop tuning accident! I will change the block back to 14.7 and see if the car runs OK. Will also smoke test the intake to verify no leaks in case that's why the previous owner made the car OL idle.

Regarding lean in boost, I used to ride 2-stroke MX bikes and am aware of how bad a lean condition can be; I was terrified when I reviewed the datalog! The MAF looks to max out around 220-230, which I think is very low for this setup. AFR is fine, then suddenly drops like a rock, but the car pulls pretty hard and no knock. While I agree that it could be a fuel pump and my lack of familiarity with modified WRX's, I also think it could also be possible that the O2 sensor is reading incorrectly and fueling is actually OK (otherwise I'd expect serious knock!). I also have a fuel pressure gauge hooked up and taped to the windshield for testing, so could do a pull with that setup and look for a fuel pressure drop, that should be interesting I'll find out either way once I install the wideband/new O2!

Re: Datalog, there was one attached to the original post, but it was pretty lengthy and the WOT portion of it was difficult to find. A shorter datalog having a WOT portion can be viewed/downloaded here: https://www.dropbox.com/s/zbu8o9g7ex...log40.csv?dl=0
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Old 07-26-2018, 10:49 AM   #7
currancchs
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Member#: 488200
Join Date: Jul 2018
Location: Brookline, NH
Vehicle:
2006 WRX TR
World Rally Blue

Default Thanks/Good luck

Quote:
Originally Posted by contaminatrix View Post
i think i have the same problem as you OP. unfortunately for me, I can't pull my map and I have no cables that can do so. I'm using btSSm to log.

my afr sensor needs to be toyed with to work. one time i'll start the car and it doesn't read. after some tlc and massaging it wakes up and reads (after an ecu reset however).

i think my mapper also put me in permanent open loop. i see idle at ~12.5 - 13.9 during warm up. when i begin to drive it drops to around 11.0, when it's fully warm it idles at 15.2.

during boost, as you can see here, my afr goes lean. granted my intercooler is useless (evidently from my rising intake temp) but it should become richer as air flows.

mods
SD tune
pinks
tbe
cai
255 lph with voltage relay hardwire mod
inline fuel filter
3port bcs
td05-16g hw
sti-size tmic
93 octane
max boost 1.35-1.42 bar




do you consume more at idle than you normally would?
have you also tested the pump's flow rate?
Hi again contaminatrix, couldn't see the picture, not sure if it's a problem on your end or mine. Re: consuming more at idle, not sure what you mean. If you're talking about fuel consumption, I'm not sure how I'd measure that. Sorry if this is a term I should understand, I'm relatively new to Subaru tuning. Re: the pump flow rate, I have not tested this yet, but do have a fuel pressure gauge hooked into the delivery line with an extension on it so that I can read while driving, but haven't gone WOT with it on yet. Will perform a flow rate test at some point during troubleshooting, if not solved before I get to that point. Thanks for the suggestions. Hope you are able to resolve your issue as well!
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Old 07-26-2018, 04:58 PM   #8
contaminatrix
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Member#: 435611
Join Date: Dec 2015
Chapter/Region: International
Location: Nairobi
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2002 SG5-2.0-XT-JDM
45A, originally 18L

Default

I don't know what's happening with the photos. How does Google photos work?? Can't embed anything.

https://photos.app.goo.gl/aMACTD3Qhk2jvvF39

Anyway, please keep us updated coz chances are what you fix will also be my fix. I have an extra 255 lying around which I'll put in tomorrow and do another log.

For consumption, yes I meant fuel. Do you see the gauge move or black smoke as you idle? Agreed you should be knocking... Actually you should have exploded by now hehehe. Why the ecu isn't picking it up is quite something. Your knock sensor is working right?

When you get to install the afr let us know. I believe it's just being stubborn. Or the pump flow rate. Check also the voltage at the pump when at 100% duty cycle.
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Old 07-26-2018, 06:21 PM   #9
currancchs
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Member#: 488200
Join Date: Jul 2018
Location: Brookline, NH
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2006 WRX TR
World Rally Blue

Default Thanks/Good Luck!

Quote:
Originally Posted by contaminatrix View Post
I don't know what's happening with the photos. How does Google photos work?? Can't embed anything.

https://photos.app.goo.gl/aMACTD3Qhk2jvvF39

Anyway, please keep us updated coz chances are what you fix will also be my fix. I have an extra 255 lying around which I'll put in tomorrow and do another log.

For consumption, yes I meant fuel. Do you see the gauge move or black smoke as you idle? Agreed you should be knocking... Actually you should have exploded by now hehehe. Why the ecu isn't picking it up is quite something. Your knock sensor is working right?

When you get to install the afr let us know. I believe it's just being stubborn. Or the pump flow rate. Check also the voltage at the pump when at 100% duty cycle.
Thanks again for the suggestions. No black smoke or visibly-moving fuel gauge (that would be a crazy amount of fuel use at idle! I would expect a heavy stench of gas in the oil as well!). I do believe that my knock sensors are working, but should probably graph them as a sanity check. Let me know if the Walbro takes care of things for you!

Re: your AFR readings, I'm not positive that you are open loop all of the time, at least at idle. During warmup, it's normal to be OL, only odd to be OL once fully warmed up (or at least the primary/upstream O2 being warm enough to start reading). 15.2:1 once warm sounds like closed loop to me, although could certainly be OL if tuned that way, but typically I think people like to stay a tad rich, so I doubt your tuner would have intentionally tuned the car to run OL @ 15.2:1 @ idle, but who knows. The very rich mixtures during normal driving do sound like OL though; maybe your tuner set the OL transition very low? If you can get a Tactrix cable, you should be able to monitor the OL/CL status block to confirm your suspicion that your car is in OL when it shouldn't be. I believe that 7 is OL during warmup, 10 is OL post-warmup, and 8 is CL.

Edit: I think that warmup open loop is slightly different from warm open loop. Warmup open loop, I think, uses a few sensors that aren't used during warm open loop, i.e. it doesn't use the O2 sensor for AFR, but does use other sensors that don't need to be hot to work.

Edit #2: Re: the pictures not uploading properly, I use a free imgur.com account to host pictures then copy/paste the "BB Code" link (click on the picture, once uploaded, and you'll have a bunch of links in slightly different formats) to a forum post and that seems to work well for me. If someone else knows of a better/more preferred way to upload pictures, let us know!

Last edited by currancchs; 07-27-2018 at 11:51 AM. Reason: Added information following "Edit:"
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Old 07-27-2018, 12:00 AM   #10
currancchs
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Join Date: Jul 2018
Location: Brookline, NH
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2006 WRX TR
World Rally Blue

Default

Just pulled the fuel pump to check on the filter and hose (someone else on the forums had a similar issue that wound up being traced to a split hose connecting the pump to the OEM, in-tank filter). It must have been on there a while, as there was a thick layer of crud covering everything. In-tank/pre-pump filter was a little dirty looking too. Turns out the pump is not a Walbro 255lph, its a "unisia jecs a42h24 022". I think this is an OEM sti pump. Not sure if its rated 145lph (same as '06 wrx stock pump) or 165lph, but, either way, a far cry from the 255lph I was told was on there and, I suspect, insufficient for a td05-20G @16psi... Ordered a Walbro/filter. Will provide update post-install.


Last edited by currancchs; 07-27-2018 at 11:49 AM. Reason: Added Picture of Pump
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Old 07-29-2018, 08:01 PM   #11
contaminatrix
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Join Date: Dec 2015
Chapter/Region: International
Location: Nairobi
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2002 SG5-2.0-XT-JDM
45A, originally 18L

Default

oh cool! so it seems the pump was insufficient. i'll be waiting for the post-walbro update.
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Old 09-05-2018, 11:56 AM   #12
currancchs
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Join Date: Jul 2018
Location: Brookline, NH
Vehicle:
2006 WRX TR
World Rally Blue

Default Sorry for the long delay...

Apologies for the delay in getting back to you guys, got busy with other stuff and this project got put on the backburner for a bit. Anyways, seems to be resolved now, but not sure what exactly was the cause of my issues, as I resolved a fair number of issues before testing the vehicle.

These resolved issues included:
-Exhaust leaking slightly at downpipe (right-most stud hole stripped and previous owner repaired with nut and bolt, but the nut didn't lay flat on the backside of the exhaust housing) - I repaired with helicoil and OEM stud/nut and new 5 layer OEM gasket
-Turbo wastegate preload maxed out (tight) by previous owner, I loosened it up a bit to a more reasonable (IMHO) 3 turns tighter from no preload
-OEM STI fuel pump replaced with Walbro 255lph unit
-Boost leak from turbo compressor housing caused by missing wastegate actuator bolt repaired (coolant line was blocking access to the bolt, so re-routed and installed new bolt) (previous owner had coolant intake and outlet in top ports on each side of turbo, I moved the coolant intake to the bottom port to facilitate coolant flow during engine off cooldown)
-MAF reading low at idle (~1.3g/s) resolved by cleaning MAF (now see 3g/s at idle) and air filter

With these changes, the car now settles at ~11:1 under WOT and stays there throughout the rev range. Boost builds MUCH earlier too, although I'm not sure exactly why (boost used to start building just before 4k RPM, now builds just after 3k RPM). Boost is fluctuating a bit under WOT and not peaking as high as before, but I believe this to be a tuning issue relating to the wastegate preload change. I will be tuning this, but not before installing a new wastegate actuator that has a slotted mounting bracket, primarily to resolve an issue of the wastegate actuator being at a slight angle to the wastegate, which doesn't appear to be causing any issues, but does bother me.

As an aside, vacuum at idle is ~22-20 inHg, which seems strong to me, maybe even a bit on the high side, although I'm not sure that it can be too high or what might cause an overly-high reading (don't think it is high enough to be considered abnormal, but mostly see people mention 18inHg as expected).

Pictures of repairs and gauge install below:






Thanks for all of the help guys!
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Old 09-16-2018, 05:50 PM   #13
NSFW
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Location: Near Seattle, WA
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05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

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Glad to hear you got it sorted out.
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