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09-08-2003, 10:21 PM | #1 |
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Need experts! Open loop fueling coming on too slow...
Hi,
My car seems to take too long to shift from closed-loop to open loop fueling. I think a lot of other 04's have this problem. First, my engine mods: 04 WRX wagon, vf34, UTEC, walbro 255 pump, STi injectors, HKS uppipe, TXS turbo-back exhaust. Here's the situation: when I go to wide-open, it takes the ECU a LONG time to stop fighting for stoich fueling. On my UTEC logs, it's typically 8-15 log cycles at WOT and full boost before the injector duty cycle jumps dramatically (typically 20-25%) between 2 cycles and the AFR starts to read "rich" (>12.0 AFR). For those cycles, the ECU is still trying to force stoich fueling. Because of this, I've had to pull 1-4 points of timing and more than 2 pounds of boost off my very strong dyno-tuned 91 octane map. I do not usually have this problem in a long sustained pull, such as a dyno pull or a long, fast pull from, say 3K, and I think this is because the ECU has time before high loads are reached to switch to open-loop fueling. My map was dyno tuned to a spot-on 11.0, and the car was very strong on 91-octane pump YooHoo. On the road, though, I have problems. If I'm cruising along under boost but at revs that will bring me to high boost, say 4500, and roll into WOT, those 8-15 cycles at stoich fueling but full boost and strong timing will cause det at anything like my full timing and boost settings. It sometimes causes det even on my ridiculously de-tuned map. This is why I've pulled so much timing and boost out of a strong map, leaving perhaps 30awhp on the table. This is just tuning around the problem, not solving the problem, and I want to SOLVE it. What I think I need is a way to get the ECU to go to open-loop fueling faster. From what I've seen, with other people's posted logs, 02 and 03 cars don't seem to have this problem, at least not as seriously as 04 cars. I've seen posted logs from several 04 cars with this same issue. Is there a way to re-flash the ECU, trick it, or anything else to make it react more quickly? I'm SURE I could go back to my awsome, strong map if I could get the ECU to give up stoich faster. Thanks in advance, Sean
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09-09-2003, 09:49 AM | #2 |
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23 views and no comments? Something, anything, please...
-Sean |
09-09-2003, 09:58 AM | #3 |
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It would be nice to see the logs for review.
Tom |
09-09-2003, 11:47 AM | #4 |
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Logs? No problem...
Notice how the injector duty shoots up from 42 to 62 right at 4997 rpm. This is NOT where the switchover always occurs, so it's not acceptable to just try to bump fuel there or anything. I think this was a third gear pull, there was no det, notice how little boost I'm running there. Code:
3663 2.3 3 17 0 0 14.8 28.5 17 ECU. -5.5 ECU. 2.7 3711 1.9 2.8 13 0 0 14.9 34.5 14 ECU. -5.5 ECU. 2.6 3720 0.4 2.5 8 0 0 14.3 40.4 8 ECU. -5.5 ECU. 2.2 3728 -2 2.3 8 0 0 15.1 41.1 8 ECU. -5.5 ECU. 2.2 3775 -4.1 2.9 20 0 0 12.7 37.3 11 ECU. -5.5 ECU. 3 3716 -3.2 3.3 78 10 0 14.1 25 6 19 -4 175 3.1 3762 -0.6 3.4 100 30 0 12.7 17.4 28 17.4 -3.8 175 3.4 3935 3.5 3.7 101 40 0 12.3 13.7 32 17.4 -3.2 175 3.6 4025 8.2 3.7 101 50 0 13.7 12.9 36 18.5 -5.2 175 3.5 4182 11 3.7 101 70 0 13.9 14.2 36 19.2 -5.4 175 3.5 4208 12.5 3.7 101 70 0 13.4 15.1 35 19.4 -5.5 175 3.5 4235 13.3 3.8 101 60 0 14.2 14.3 36 20.1 -5.6 175 3.5 4380 13.3 3.8 101 60 0 14.6 13.7 37 20.5 -5.7 175 3.7 4492 13.1 3.8 101 70 0 14.9 13.2 38 20.7 -5.8 175 3.6 4553 13.1 3.9 100 60 0 14.7 13.5 40 21 -5.9 175 3.6 4649 13.1 4 101 60 0 14.7 13.4 41 21 -5.9 175 3.7 4662 13.1 4 101 60 0 14.6 13.6 42 21 -5.9 175 3.7 4916 13.1 4 101 70 0 14.8 14.4 43 21 -5.9 175 3.7 4837 13.5 4 101 70 0 14.7 15 43 21.2 -6 175 3.7 4997 13.7 4 101 70 0 14.5 15.7 42 21.9 -6.1 175 3.7 4975 14.1 4 101 70 0 14.6 16.7 62 22 -6.2 175 3.7 5035 13.5 4 101 60 0 rich 19 66 22 -6.2 175 3.8 5159 13.7 4 101 60 0 rich 19.5 68 22 -6.2 175 3.8 5274 13.7 4.1 101 70 0 rich 19.6 68 22 -6.4 175 3.8 5350 13.5 4.1 101 70 0 rich 19.6 70 22.3 -6.7 175 3.8 5376 13.7 4.1 101 60 0 rich 20 70 22.6 -6.7 175 3.9 5455 13.9 4.1 101 70 0 rich 21.5 68 22.9 -7 185 3.8 5574 13.5 4.1 100 60 0 rich 21.4 70 23.3 -7.3 185 3.9 Code:
2231 -4.3 2.4 39 0 0 14.4 33.8 9 ECU. -5 ECU. 2.3 2579 -2 2.5 39 0 0 15 33.2 12 ECU. -5 ECU. 2.4 2560 -0.2 2.6 41 0 0 13.8 31.5 12 ECU. -5 ECU. 2.4 2364 0 2.6 47 0 0 13.8 29.8 11 ECU. -5 ECU. 2.5 2097 0.4 2.5 51 0 0 14.4 30.9 10 ECU. -5 ECU. 2.3 1737 1 2.4 53 0 0 14.2 25.8 8 ECU. -5 ECU. 2.2 1579 1.4 2.2 58 0 0 14.5 21.3 7 ECU. -5 ECU. 2.2 1963 1.6 2.5 72 10 0 13 30.5 8 33 -5.8 500 2.3 2116 1.9 2.5 72 10 0 16.4 30.8 9 33 -5.4 500 2.4 2283 2.1 2.6 73 10 0 15.4 31.4 10 32.7 -5.4 500 2.4 2620 2.1 2.7 73 10 0 15 32.1 13 28.5 -5.1 500 2.6 2766 2.3 2.8 73 10 0 14.8 31.2 14 26.6 -4.9 500 2.7 3033 2.7 3 73 20 0 14.5 28.6 17 24.2 -4.3 220 2.8 3290 3.1 3 73 20 0 13.9 26.4 19 20.1 -3.8 220 3 3591 3.9 3.2 83 20 0 12.5 25.3 19 18 -4 220 3.1 3880 4.9 3.3 101 30 0 16.2 21.6 27 18.6 -4.5 220 3.3 4161 6.3 3.7 101 40 0 15.2 19.6 32 19.2 -3.5 220 3.5 4662 8.4 3.9 101 50 0 14.8 16.6 41 24 -5.9 220 3.7 5073 10.2 4.1 101 60 0 15.3 21.6 47 24.5 -6.6 220 3.8 5640 11.8 4.2 100 60 0 rich 22.4 76 25.8 -7.7 220 3.9 6060 12.9 4.2 101 60 0 rich 24.2 80 26 -7.5 220 4 6472 13.3 4.3 101 60 0 rich 28.1 85 26 -7.2 220 4 6930 13.7 4.3 83 70 0 rich 29.3 87 26 -6.2 220 4 6447 10.4 3 0 0 0 12.7 10.8 6 ECU. -5 ECU. 2.8 Code:
3809 -0.8 2.9 18 0 0 14.7 33.8 16 ECU. -5 ECU. 2.8 3796 -0.4 2.9 18 0 0 14.7 33.6 16 ECU. -5 ECU. 2.8 3770 0 3 19 0 0 14.4 32.4 17 ECU. -5 ECU. 2.8 3831 1 3.3 85 10 0 16 26.1 27 ECU. -4.3 215 3.2 3835 3.5 3.6 101 30 0 13.3 21.6 28 17.6 -3.8 215 3.5 3926 6.3 3.7 101 50 0 13.8 12.8 31 15.8 -3.7 215 3.6 3940 10.2 3.7 101 70 0 14.7 11.9 33 16.2 -4.4 215 3.5 3987 13.7 3.7 101 80 0 14.6 12.4 34 16.6 -4.4 215 3.5 4001 14.9 3.7 101 70 0 14.9 13.1 33 16.6 -4.6 215 3.5 3977 15.3 3.8 101 70 0 14.5 12.8 35 17 -4.6 215 3.6 4016 15.1 3.7 101 70 0 14.7 12.7 36 17.6 -4.6 215 3.6 4095 14.7 3.7 101 70 0 14.9 12.8 36 17.2 -4.6 215 3.6 4079 15.1 3.7 101 70 0 14.7 12.7 36 17.4 -4.6 215 3.6 4145 15.1 3.7 101 70 0 14 11.8 35 17.4 -4.6 215 3.7 4120 14.9 3.9 101 70 0 14.3 11.8 36 17.5 -4.6 215 3.6 4192 14.9 3.8 101 70 0 14.8 9.1 37 17.8 -4.6 215 3.7 4214 15.1 3.8 101 70 0 14.6 16.6 36 17.9 -4.6 215 3.7 4240 15.5 3.8 101 70 0 14.8 16.6 37 17.9 -4.6 215 3.7 4273 15.9 3.7 101 70 0 12.5 16.6 52 18 -4.7 215 3.7 4312 15.7 3.9 101 70 0 rich 16.3 53 18.3 -4.7 215 3.6 4351 15.7 3.8 101 70 0 rich 16.2 54 18.4 -4.8 215 3.7 4363 15.7 3.9 101 70 0 rich 15.7 55 18.5 -4.8 215 3.7 4403 15.5 3.9 101 70 0 rich 16.3 56 18.5 -4.8 215 3.7 4409 15.5 3.8 101 70 0 rich 16 57 18.8 -4.8 215 3.6 4438 15.3 3.9 101 70 0 rich 16.3 59 18.8 -4.9 215 3.7 Obviously, the lower the revs where the switch occurs, the lower the load and thus the lower the jump has to be, but you can see a consistent jump. I've got literally hundreds of examples, this effect is just about 100% consistent. Someone in another post mentioned that they use an 03 ECU in an 04 to get more agressive timing and other performance benefits. Since the 04 (or, at least, my 04) has this problem, would switching to an 03 ECU solve it? Can an 04 run on an 03 ECU? Thanks in advance, Sean |
09-10-2003, 12:56 PM | #5 |
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Bump. If anyone knows an answer, I'd really appreciate it...
-Sean |
09-10-2003, 01:00 PM | #6 |
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dude your using a piggyback fuel and timing computer, they are just slow in nature anyways, get real engine manegment or a reflash to fix your problems
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09-10-2003, 01:23 PM | #7 |
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Does the UTEC effect when the ECU goes to open-loop fueling from closed-loop fueling? I don't think that it does, but I certainly could be wrong. All the UTEC does for fueling is adjust the MAF, which has a pretty limited effect on closed-loop fueling, from what I understand.
Besides, lots and lots of people seem to run UTECs on 02s and 03s and don't see this issue at all. Their systems still switch from CL to OL at 63% TPS. Mine does not seem to. What I'd like to know is why this is so, so I can fix it. I'll get a reflash if I need to. But I also don't want to lose the ability to switch from 91-octane to 100-octane gas, and the UTEC makes that easy. Thanks, Sean |
09-11-2003, 03:55 AM | #8 |
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This is something I have not looked at as of yet. But from what is in the EcuTeK software I can see there is a Open/Closed Loop Fueling at a Throttle Theshold of 25% and Open/Closed Loop Fueling at a Load Threshold of 6ms.
This gives me the impression that at least 25% throttle and under a consistent load for more then 6ms then the Closed Loop will switch over. So my guesses are it will come on when you are cruising down the highway at a consistent load for 6ms, which will give you better fuel economy but under quick accelerations at any throttle, load and boost the values it will run in open loop mode. Here are my reasons for this design, which is actually sheer genius by Subaru. 1. It takes up less space on the board, so other cool features can be added. 2. This is a common problem on how to resolve the pinging and knock issues under quick changes in loads, which are #1 reason for pinging and knocking. Subaru solved this problem with the ECU by using some amazing thinking. So simple but yet works so well. 3. A possible idea under full boost at a consistent load level, which happens while the car is already in full boost and the load is dropping slowly, the ECU can actually retune the car for optimal performance. Possible, what amount of time would be required for this though? Bill Knose I-SpeedUSA |
09-11-2003, 12:27 PM | #9 |
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Skywalker,
That is AWSOME information. It's the first time I've had someone tell me what the software actually says. Unfortunately, it's not what my car seems to want to do. I've added DeltaDash to my logging tools, and from what I've been told, the Air/Fuel correction zeroes out when you're in OL fueling. That makes sense, really. Well, as I mentioned above and in other posts, I was watching injector duty percentages and AFR to try to guess when the car completed the cutover. I typically see the car fighting for stoich for 2-3 seconds, then there is a sudden jump in ID% and the AFR immediately drops to "rich". In DeltaDash, A/F correction zeroes out at exactly the same point the ID% increases, and the AFRs drop to rich. I did a bunch more runs today, not at WOT. I can confirm that it will cutover under acceleration as low as 30%. However, I can also confirm that it's always AT LEAST 2 seconds from the time I start accelerating until the time it cuts over to OL fueling. Is it possible that the firmware in my ECU, or ones just like mine, are configured for a 2 second cutover time? This would DEFINITELY explain why lots of people with 04s have similar problems to mine. The nice thing is that if that's the case, it's something that can probably be EASILY flashed out of the ECU. wooHOO! -Sean |
09-11-2003, 12:45 PM | #10 |
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I want to see more on this...
And i'd like to know if anyone knows if this can be changed through subaru diagnostic tools... or it must be reflashed by some facility. |
09-11-2003, 12:55 PM | #11 |
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On the bright side, it looks like something that will PROBABLY be fix-able with a reflash of some kind...
-Sean |
09-11-2003, 01:05 PM | #12 |
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I just re-read Skywalker's post there, and will post a counter-view:
I DON'T think that it will ever switch to OL during highway "cruising". OL should never give better fuel economy on a subie - CL already runs at stoich and OL is designed to be richer than stoich for higher-speed runs. Also, I've cruised for long, long distances at over 100mph, and my throttle is never close to 25% at that speed. I think that they designed this to allow faster-smoother transitions to OL fueling, and to make sure that, say, a long 40% throttle pass doesn't run too lean. Of course, that STILL doesn't explain why my car, and a lot of other 04s, seem to take more like 2 seconds to make the CL-OL cutover. Thanks again for the raw data, Skywalker, it answers a huge question of mine... -Sean |
09-11-2003, 02:19 PM | #13 | |
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Quote:
Thanks for the great responses. I agree OL will never switch on during highway "cruising" I must have given the wrong impression on that. Like you said CL already runs at stoich and OL is designed richer for boosting etc... You know what I misread your original post about, I thought you were talking about OL->CL not CL->OL. Now that is a whole other story. What might be going on in the ECU, Subaru might have been thinking, that loads are constantly changing while driving, and might have put in a fail safe function that will keep the car running in closed loop even under changes to load under a certain throttle % for a certain amount of time. Wow, long sentence... As the loads don't change a whole lot down change a lot during part throttle even to full throttle. Basically Subaru was trying to think to much and tried to cover how the average driver would drive the car or how the cruise control would drive the car, as many poeple use cruise control these days. I am sure there is a parameter in the ECU that can change this value, it is just finding it and actually switching it to 0 or something very small. Bill |
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09-11-2003, 02:23 PM | #14 |
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Ah, sweet, thanks. I'll get this worked out soon...
-Sean |
09-12-2003, 10:13 PM | #15 |
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lets keep this thread active, this is very important for EVERYONE with an 04 and a utec!
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09-12-2003, 10:50 PM | #16 |
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When the EPA was considering its final rule that introduced the US06 Supplemental Federal Test Procedure (SFTP), better known as the "Aggressive Driving Schedule," they came very close to mandating a 2-4 second delay from when the throttle moved from partial to wide-open and when the A/F ratio could switch from "stoichiometric control" (closed-loop) to "enrichment" (open-loop). That proposal was aimed at "high-performance" engines and it appears that it was dropped from the final regulations. However, given that Europe also has its own "Aggressive Driving Schedule" and might have chosen to adopt a "delay" mandate (I have no idea what their regs say), and given that the WRX is a "world car," it's not inconceivable that the 2004 WRX has a built-in timer which delays the switchover from closed-loop A/F control to open-loop A/F control when the throttle goes wide open.
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09-13-2003, 03:43 PM | #17 |
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I dont think they would ever give the ECU instructions that could damage the engine in the long run, even an unmodded engine... running stoich at WOT is bad, even if it doesent knock, because it leaves open the oppertunity to knock
im not an expert, but thats just common sense speaking there |
09-13-2003, 04:53 PM | #18 | |
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Quote:
I guess then almost half of ALL people with modded WRX's dont have "REAL" engine management. This problem has NOTHING to do with a utec problem!! Yes standalone EM or a reflash would solve it, but, just because its a piggyback computer doesnt make it slow or bad!! There are many people on this forum that have very very high performance motors that are running fine on a utec if well tuned!! Richard Jackson |
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09-13-2003, 08:43 PM | #19 | |
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09-22-2003, 09:03 AM | #20 |
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Hey Jon,
I hadn't read the US06 aggressive driving schedule documentation. Thanks for the heads up. It does seem as if it accurately describes my problem. I wonder if it's all 04s or if some are not bothered by this problem, depending on ECU version? If people are or are not seeing similar things, please post your ECU information, if you can. Just copy down all of the information on the ECU cover. If you have a UTEC, and this really applies to UTEC users, you'll have to remove the UTEC from the ECU. Here's mine... 6G 22611AH791 112200-5182 12V (barcode) 225182K Later, Sean |
11-29-2004, 09:35 PM | #21 |
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subscribe
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11-29-2004, 11:00 PM | #22 |
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not only are you a year off, but the solution has been discussed, tested, and in the field since spring
Jorge (RiftsWRX) www.ProjectWRX.com |
11-29-2004, 11:18 PM | #23 | |
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So what was the solution, besides a Tuner Reflash? Did suby do anything bout this? I'm wondering cause I have an 05. |
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11-29-2004, 11:30 PM | #24 |
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Subaru has done nothing.
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11-29-2004, 11:36 PM | #25 | |
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