Hydra, Closed loop being loopy!

[Sko]

So I've got my base fuel without closed loop set very close to what it should be, in some cases it will get to 15.5, others down to mabe 12 under low low vaccume, but it mostly stays between 13 and 15.

Now I turn on closed loop and it does some pretty wierd stuff, like at idle it wants to run 10.5-11.5, then I'll be driving and it might run 14.5-15.2 or so every now and then, but it really likes to stay around 11.5-13, pretty rich. And every so often it will run WAYYYYY lean between -13inMg and -5inMg, like up in 18-19.9(max for my wideband reader). Why is it doing this?

When I turn off closed loop my readings are fine in that range, around 14.7-15.5 no where near 18 or 19.

I'm using 2.17 w/ my stock rear O2 sensor (I did try it with my wideband to narrowband output from my wideband sensor and it seemed to work better on the stock one until now).

And I know the stock one is reading correctly because I can watch the 1.0 change back and forth from 0 to 1 on the tuning screen depending on lean or rich.

One thing I did notice though is only 1 on the left changes from 0 to 1, the one on the right stays a constant 1, I dont know if that has anything to do with anything though.

Any help greatly appritiated, as always!

Nick

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[Sko]

bump?

[Element Tuning]

Nick,

Since you don't have one of my base maps it's really hard to say as it depends on your "closed loop limit" map and your sensor source settings.

Thanks,
Phil
www.elementtuning.com

[jblaine]

Yeah, I didn't reply because there's a lot more info needed.

[Sko]

Closed loop limit is 3 up to 4000rpms, and from 4800 on is 765.

Any other information needed?

[jblaine]

What are your CL sensor source settings?

[Sko]

Left U/HEGO on both

[Sko]

Well I guess I dont really need closed loop if the car runs better with out it.

[jblaine]

I don't know how much you know, so don't consider this an insult if you already know this stuff:

* I've never used CL with the OEM rear O2 sensor

* It doesn't sound to me like you have a well-tuned fuel map to begin with. Things shouldn't be all over the road. You need to spend a great deal of time working on the off-boost section of the map, with steady throttle and load while adjusting things to 14.5:1 or so. Across all RPMs.

* Without a well-tuned base fuel map that is very close to your target, I'd guess the CL system is going nuts trying to figure out what to do, in real-time.

* For comparison, the fuel map I've been poking around at for 8 months now on and off, never goes richer than 14.2 and never goes leaner than 14.7 in all vacuum conditions with CL off.

[Element Tuning]

Originally Posted by jblaine

I don't know how much you know, so don't consider this an insult if you already know this stuff:

* I've never used CL with the OEM rear O2 sensor

* It doesn't sound to me like you have a well-tuned fuel map to begin with. Things shouldn't be all over the road. You need to spend a great deal of time working on the off-boost section of the map, with steady throttle and load while adjusting things to 14.5:1 or so. Across all RPMs.

* Without a well-tuned base fuel map that is very close to your target, I'd guess the CL system is going nuts trying to figure out what to do, in real-time.

* For comparison, the fuel map I've been poking around at for 8 months now on and off, never goes richer than 14.2 and never goes leaner than 14.7 in all vacuum conditions with CL off.

You hit the nail on the head. For closed loop to work properly and be an asset you need to have your fuel map very close to your target AFR Table. It can then fine tune your fuel map to compensate for various environmental conditions not optimally covered by compensation maps.

Also if you are running 14.7 feed back that may be too lean for your setup. Many cars I tune fall on there face at 14.7-15.0 and really need to be closer to 14.5 with some even richer. Cars with only minor modifications can run 14.7-15.0 all day long but not many cars running Hydras have minor modifications.

Thanks,
Phil
www.elementtuning.com

[Sko]

Originally Posted by jblaine

* I've never used CL with the OEM rear O2 sensor

I've tried it using a wideband with a narrowband output, it worked, but not as good as it does with the OEM O2.

Originally Posted by jblaine

* It doesn't sound to me like you have a well-tuned fuel map to begin with. Things shouldn't be all over the road. You need to spend a great deal of time working on the off-boost section of the map, with steady throttle and load while adjusting things to 14.5:1 or so. Across all RPMs.

I will admit my AFR's are close, within .5-.8 at most points and perfect while on the freeway, I just wouldn't expect the closed loop system to lean my AFR's way out to 18-19 and leave them there, which is the trouble I was having with it.

And with an open loop fuel map at 14.5 throughout all rpms, why would you need closed loop to adjust to 14.7 if you could do it yourself? I understand the closed loop system only makes minor changes, but why do you need it if your already at where you want to be?

Originally Posted by jblaine

* Without a well-tuned base fuel map that is very close to your target, I'd guess the CL system is going nuts trying to figure out what to do, in real-time.

I thought the closed loop system was supposed to adjust fuel in real time? And by using long-term learning that it would find the spots that are consistantly lean/rich and learn under those loads and at those rpms that it would add or remove fuel to compensate.

Originally Posted by jblaine

* For comparison, the fuel map I've been poking around at for 8 months now on and off, never goes richer than 14.2 and never goes leaner than 14.7 in all vacuum conditions with CL off.

So what I'm getting is that closed loop is a feature that doesn't really control much fuel, but when you have all your afrs REALLY close to what you want (14.7), then it will make that extra tiny adjustment to net 14.7?

I suppose I thought it had more power than it does, and by using my unperfected fuel map in closed loop the system just guesses.

Thanks for all the responses and advice, I'll just keep plugging away at it until I'm at that "perfect" time in my fuel map to use closed loop.

Nick

[Element Tuning]

Originally Posted by Sko

I've tried it using a wideband with a narrowband output, it worked, but not as good as it does with the OEM O2.

I will admit my AFR's are close, within .5-.8 at most points and perfect while on the freeway, I just wouldn't expect the closed loop system to lean my AFR's way out to 18-19 and leave them there, which is the trouble I was having with it.

And with an open loop fuel map at 14.5 throughout all rpms, why would you need closed loop to adjust to 14.7 if you could do it yourself? I understand the closed loop system only makes minor changes, but why do you need it if your already at where you want to be?



I thought the closed loop system was supposed to adjust fuel in real time? And by using long-term learning that it would find the spots that are consistantly lean/rich and learn under those loads and at those rpms that it would add or remove fuel to compensate.



So what I'm getting is that closed loop is a feature that doesn't really control much fuel, but when you have all your afrs REALLY close to what you want (14.7), then it will make that extra tiny adjustment to net 14.7?

I suppose I thought it had more power than it does, and by using my unperfected fuel map in closed loop the system just guesses.

Thanks for all the responses and advice, I'll just keep plugging away at it until I'm at that "perfect" time in my fuel map to use closed loop.

Nick

It's important to have your AFR as close as possible. If not then run "Autotune" to get it closer to your target. You don't want the regular closed loop system to tune your car as it has a range that it can work within about 25% but honestly you want to be in the single digits without long term learning. What is likely happening is that it's storing very large values in long term learning and then it struggles to adjust the fuel back when there is a demand as its skewed too far. Autotune to get yourself closer, smooth your map, and then enable Closed Loop.

I typically run Closed Loop with the WB Target Table on all cars I tune and it's just about seamless.

The only time you should see AFRs of 18 or higher is under deceleration where you'll see up to 20.8 which is due to the system cutting fuel as it's not required under deceleration.

Please post a screen shot of your fuel map so we can evaluate it. It should look something like this:


Thanks,
Phil
http://www.elementtuning.com

[bboy]

I thought that closed loop fueling had to be within a certain percentage of the the target AFR as well. So if your fuel map is off by more than something like 30% the computer does nothing.

Put another way: the computer will only pull or add a certain percentage of fuel under closed loop with a reference to that particular load site. Is that right Phil?

[Element Tuning]

Yes, I think I understand what you are saying. It will add or subtract about 25% per given load cell. This is also somewhat of a built in failsafe in case of sensor failure. You really do not want to give it much more authority.

Thanks,
Phil
www.elementtuning.com

[bboy]

That's what's great about Phil's maps he's already in that margin of 25%. That's still a lot of fuel variation. I rarely change more that 5-10%, and usually less than 2% of the base PWM value.

[Sko]

Hey, not enabling long term learning is a very good idea, I will try that!

My fuel map is kinda ugly right now, but I suppose I'll post a screen sometime.

[Brydon]

Other than the tuning is your car running well with the hydra... Haven't talked to you in awhile.

[Element Tuning]

Originally Posted by Sko

Hey, not enabling long term learning is a very good idea, I will try that!

My fuel map is kinda ugly right now, but I suppose I'll post a screen sometime.

That's ok but if you're embarrassed by your fuel map it's likely your problem is within the fuel mapping. Hey we all have to start as novices but at least you're learning

Thanks,
Phil
www.elementtuning.com

[ImprezaRSX]

I may have missed something....
do you have the wideband and the rear o2 plugged in?

I can't even plug in my rear o2 sensor if my wideband is plugged in. If I do the afr's oscillate pretty dramatically regardless of any settings. I talked with Hydra and aparently its a known issue.