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QWKSNKE
01-12-2005, 05:19 PM
I thought the only temp that determined closed loop/open loop was the 02 heaters.

If what brad says is true, why does the car go into closed loop 2 minutes after startup regardless of engine temp?

95GTMan
01-12-2005, 05:42 PM
Or you could just pull the Binary up using the TwEECer software and see where it's set at. :shrug:


You said TwEEZer. :jester:

Italian LX
01-12-2005, 05:49 PM
You said TwEEZer. :jester:
:lol:

Sendero
01-12-2005, 05:52 PM
Mine goes CL on a time limit. The engine temp is only used for the ECT adders for spark and fuel.

Wicked
01-12-2005, 07:19 PM
From the "Inner Workings of the EEC-IV"

There are two methods of EEC fuel control, Open Loop and Closed Loop. The EEC starts in Open Loop and based upon time and engine parameters such as engine temperature, changes to Closed Loop.

QWKSNKE
01-12-2005, 09:43 PM
From the "Inner Workings of the EEC-IV"

There are two methods of EEC fuel control, Open Loop and Closed Loop. The EEC starts in Open Loop and based upon time and engine parameters such as engine temperature, changes to Closed Loop.

guess the tweecer stuff is wrong then :shrug:

Wicked
01-13-2005, 05:11 AM
guess the tweecer stuff is wrong then :shrug:

Noone said that, TwEECer is not a stock ECU though right?

I'm just posting the evidence I have, none of you know-it-alls have posted anything to the contrary.

Other evidence that coolant temp affects when the ECU enters closed loop...
EEC IV Code: P0125 Insufficient Coolant Temperature to enter Closed Loop.

Italian LX
01-13-2005, 05:13 AM
. . .TwEECer is not a stock ECU though right?
Actually, the TwEECer just alters the parameter of the stoxk ECU.

QWKSNKE
01-13-2005, 05:20 AM
none of you know-it-alls have posted anything to the contrary.



I haven't because I can't rememeber where I read it at. I think that it was in the notes field of one my tweecer tables.

93Cobra#2771
01-13-2005, 08:52 AM
The ultimate decision maker on going into CL from OL is time. No matter what the engine temp is, the car WILL switch to CL after 120 sec/2 min.

There are two methods of EEC fuel control, Open Loop and Closed Loop. The EEC starts in Open Loop and based upon time and engine parameters such as engine temperature, changes to Closed Loop.
The temp is a modifier to the time. In other words, if it gets up to temp quicker, it will go into CL quicker. However, temp will not keep the EEC from going into CL after the 120 sec. limit.

To recap: Time is the ultimate factor, with temp as a modifer to that...

I'll have to do a little digging on the error code and what it exactly means. I can't figure out which paramter affects the switch, with the little bit of digging I did. BTW, the code you reference, is that a fox body or on your 01 model? If 01 model, then that is why - 94 up models base the switch to CL on the O2's temp, and has nothing to do with time. Basically switches over within a few seconds of startup, if it isn't too cold outside...

Shorty
01-13-2005, 09:22 AM
does anyone have a good link to describe what the differences in open and closed loop is? i have heard you all talk about it alot but dont know what you are actually talking about.

Italian LX
01-13-2005, 09:30 AM
does anyone have a good link to describe what the differences in open and closed loop is? i have heard you all talk about it alot but dont know what you are actually talking about.
Quick description:

Open loop uses a set table and the reading from the MAF to determine injector pulse width.

Closed loop uses the above in conjunction with feedback from the O2 sensors; the computer then comes up with a trim value that adjusts the injector pulse width in order to get closer to the commanded A/F ratio.

There are other parameters involved, but the above is simplidied to show the difference between OL and CL.

QWKSNKE
01-13-2005, 09:31 AM
Also

Open loop is used during WOT and initial startup.

QWKSNKE
01-13-2005, 09:40 AM
Noone said that, TwEECer is not a stock ECU though right?



I know you didn't say that. Didn't mean it in a sarcastic manner

Shorty
01-13-2005, 09:56 AM
so during most driving conditions the EEC is in CL. meaning that if the 02's were missing some, that the A\F would suffer. my car ran a little lean on the dyno and on initial start it wants to go dead the first time you turn it over. this was never an issue before the headers and O/R H-pipe.

TheJeanyus
01-13-2005, 10:01 AM
so during most driving conditions the EEC is in CL. meaning that if the 02's were missing some, that the A\F would suffer. my car ran a little lean on the dyno and on initial start it wants to go dead the first time you turn it over. this was never an issue before the headers and O/R H-pipe.
It's broken for good. You should just let me have it. :D

Italian LX
01-13-2005, 10:02 AM
so during most driving conditions the EEC is in CL. meaning that if the 02's were missing some, that the A\F would suffer. my car ran a little lean on the dyno and on initial start it wants to go dead the first time you turn it over. this was never an issue before the headers and O/R H-pipe.
Your dyno A/F (for the most part) has nothing to do with your O2 sensors because the CPU goes into OL under WOT.

On the otherhand, your O2 sensors do affect your trim tables which the computer will use during OL operation to adjust the pulse width according to previous logs.

Shorty
01-13-2005, 10:13 AM
Your dyno A/F (for the most part) has nothing to do with your O2 sensors because the CPU goes into OL under WOT.

:doh: that would have made sense if i would have thought a little harder.

It's broken for good. You should just let me have it.
should make you a good DD. :slap:

93Cobra#2771
01-13-2005, 11:44 AM
Here's a nice little spreadsheet I have compiled with all kinds of fun stuff on it. Although it is Fox specific, a lot of the descriptions and functions are very similar on 94+ stuff.

BTW, this is the list of tweecer paramters on the fox stuff...

Well, my file is too big to attach here (xls spreadsheet). I'll copy and paste a few things, and give a link to it in the yahoo tweecer group (you have to join to see it, but no big deal).

http://autos.groups.yahoo.com/group/tweecer/files/Documentation/
It is the file called "tweecer defs.XXXXXX.xls. I update it and change the X to the date it is updated.

Closed Loop: "Closed loop refers to the EEC watching the Oxygen sensors and monitoring and adjusting a/f to achieve stoichemetric. Closed Loop occurs at all times other than WOT and the first 120 seconds or less after startup. KAMRF values at this time are 1.000. To disable, adjust the min load for closed loop fuel control to a load the car will never see & number of hegos to "0". Adaptive should also be disabled at this time. This is also known as "Forcing Open Loop". A variant of that is to set the min load to a load the car never sees at idle, this will "Force Open Loop at Idle"."

Open Loop basically ignores O2's and works off tables.

93Cobra#2771
01-13-2005, 11:51 AM
Your dyno A/F (for the most part) has nothing to do with your O2 sensors because the CPU goes into OL under WOT.

On the otherhand, your O2 sensors do affect your trim tables which the computer will use during OL operation to adjust the pulse width according to previous logs.

Italian made a very important poinit. In other words, IF the EEC sees the load/rpm conditions in CL operation, it can apply adaptive long term memory to OL WOT runs. So, adaptive CAN affect your WOT dyno tune IF you raised fuel pressure to get more fuel at WOT.

Do a dyno tune and raise the FP to get more fuel and get your a/f just right. Then go back in a few months, don't touch anything, and more times than not, your a/f will be leaner than what it was. Kinda scary, huh?

Italian LX
01-13-2005, 11:54 AM
Do a dyno tune and raise the FP to get more fuel and get your a/f just right. Then go back in a few months, don't touch anything, and more times than not, your a/f will be leaner than what it was. Kinda scary, huh?
:werd:

This is why DSP recommends a long-term "street tune" on a car in addition to any dyno tune sessions. :nice:

QWKSNKE
01-13-2005, 12:11 PM
yeah Brian is right,

While it is something that could not be done in a day, street tuning is very important. Actually did my street tune before my car was put on the dyno. Reason being, is that if you do the dyno tune first, then have to make adjustments during street tuning, it can/will throw your WOT all out the window.

With my particular application we had probably around 6-8 hrs just in street tune. While that sounds like a lot, it set the car up where after 4 pulls on the dyno we were done. (which ='s cheaper $$$ )

Sendero
01-13-2005, 12:29 PM
I have found that EEC-V cars are more reliant on the Adaptive Strategy (AS) for Short/Long term fuel trim AND WOT fuel. This is experienced backed up with two seperate dyno sessions where the car went in to "limp mode" when making changes to OL Fuel Tables with AS enabled.

I'm beginning to think the recommendation to leave Adaptive Strategy enabled while doing your tuning is wrong.

Sendero
01-13-2005, 12:38 PM
Mine goes CL on a time limit. The engine temp is only used for the ECT adders for spark and fuel.

Figured I would quote myself since everyone discussing CL Temperature operation missed it.

Datalogged this morning to verify my thoughts. It took roughly 360 seconds for the O2's to begin switching. This means it took my car 6 minutes of idleing before it started the Closed Loop control. Engine Temp at that time was 133*, well below the "Hot Start" ECT Table of 150*. Your car WILL go into closed loop operation well below the "percieved" thermostat limit. BUT your EEC can keep the car in "start up mode" fuel tables if it doesn't reach a certain temperature.

Like with my strategy, anything below 56* it uses a mulitplier of the A/F start up mode table. Between 56* and 150* it uses just the table by itself. Above 150*, it assumes the car is warm and ready for fuel_OL_stabilzed settings.

93Cobra#2771
01-13-2005, 01:00 PM
I'm beginning to think the recommendation to leave Adaptive Strategy enabled while doing your tuning is wrong.
I don't remember how, but I THINK you can disable specific cells in the adaptive strategy tables to kill adaptive control at WOT. You'll have to do some digging on the tweecer forum or in the tweecer yahoo group to confirm, though.

QWKSNKE
01-13-2005, 01:25 PM
Figured I would quote myself since everyone discussing CL Temperature operation missed it.

Datalogged this morning to verify my thoughts. It took roughly 360 seconds for the O2's to begin switching. This means it took my car 6 minutes of idleing before it started the Closed Loop control. Engine Temp at that time was 133*, well below the "Hot Start" ECT Table of 150*. Your car WILL go into closed loop operation well below the "percieved" thermostat limit. BUT your EEC can keep the car in "start up mode" fuel tables if it doesn't reach a certain temperature.

Like with my strategy, anything below 56* it uses a mulitplier of the A/F start up mode table. Between 56* and 150* it uses just the table by itself. Above 150*, it assumes the car is warm and ready for fuel_OL_stabilzed settings.


You guys and your freaking EEC-V's

Sendero
01-13-2005, 01:26 PM
I don't remember how, but I THINK you can disable specific cells in the adaptive strategy tables to kill adaptive control at WOT. You'll have to do some digging on the tweecer forum or in the tweecer yahoo group to confirm, though.

Yeah, its the fuel_adaptive_update_rate table. You can disable the upper load settings to disable Adaptive at WOT. I was told NOT to do this for tuning by Chris Mureen. But, I believe that this is not an entirely accurate statement and here's why.

Adaptive Strategy is there so the EEC can "learn" and make small corrections based on engine and eviromental conditions. So when you are "tuning" you are basically tuning for that set of conditions which could be totally wrong in time. I believe Adaptive Strategy, while it has its usefulness, is used by the engineers as a "horseshoe" fix for tuning an entire fleet of vehicles. All they have to do it get close to desired tuning effect and let Adaptive do the rest.

As soon as I free up some time to play with the TwEECer again I am going to try some things. First, I am going to disable Adaptive Strategy totally. This ensures that the computer won't counter act any tuning changes that I make. Then using EEC_Analyzer I am going to start dialing in my fuel tables and transfer values. Once I get my KAMRFx's and LAMBSE to the desired values, THEN I will turn Adaptive back on. My thinking is that tuning the car with Adaptive off will get me very close to the optimal fuel control that my setup will require. Then with Adaptive back in control, it can make the small corrects it needs to ensure the best performance. I could cut this time down with two visits to the dyno. One trip would be for tuning only with Adaptive turned off. After that tuning is done, I would turn adaptive back on and drive it for a couple of weeks. Then its back to the dyno to verify that the "tune" is still optimal.

Italian LX
01-13-2005, 01:29 PM
Oh no, here comes the headache. :doh:

TheJeanyus
01-13-2005, 01:39 PM
:joystick:

Italian LX
01-13-2005, 01:51 PM
:joystick:
Maybe that smiley should be called :tweecer:


:D

TheJeanyus
01-13-2005, 01:53 PM
Maybe that smiley should be called :tweecer:


:D
:werd:

93Cobra#2771
01-13-2005, 02:37 PM
:lol:

Wicked
01-13-2005, 04:04 PM
The P code that I posted was for EEC IV, had nothing to do with my own car.
http://www.proficientperformance.com/tech_ecm_codes.htm#b


I have been researching and am still seeing some people say time only and some saying temp + time. Your explanation about temp being the modifier makes a lot of sense.

Lee, didn't mean to snap back at you. ;)

Wicked
01-13-2005, 04:09 PM
Your car WILL go into closed loop operation well below the "percieved" thermostat limit.

I don't think anyone thought the temp at which CL is entered had anything to do with the thermostat temp...only ECT.

Sendero
01-13-2005, 07:25 PM
I don't think anyone thought the temp at which CL is entered had anything to do with the thermostat temp...only ECT.

But it is a common misconception that if you install a 160* t-stat that your car will stay in OL all the time. Take a meander around Corral and Stangnet.

Italian LX
01-13-2005, 07:44 PM
Lee, didn't mean to snap back at you. ;)
:banned:

Wicked
01-13-2005, 08:01 PM
:banned:
...

93Cobra#2771
01-14-2005, 07:06 AM
But it is a common misconception that if you install a 160* t-stat that your car will stay in OL all the time. Take a meander around Corral and Stangnet.
Don't even get me started on that. :D

Whew, that's a doozy of a first thread in the "EEC management" forum.

Wicked
01-14-2005, 04:22 PM
Don't even get me started on that. :D

Whew, that's a doozy of a first thread in the "EEC management" forum.

:werd:

dynotnr
01-24-2005, 10:49 AM
If the transfer to CL is, indeed, time based (though I have always thought it to be switched by coolant temp) perhaps this could be the root of the Tweecer problem we were having on the black Cobra and white coupe. Even though we are monitering AFR @ WOT on the dyno, if the computer is still "counting down" to its CL switch-over point, it may be affecting the AFR on our pulls. I know on the stand alone stuff (F.A.S.T., DFI, TECIII etc) there are "cold start enrichment" and, more importantly "Hot start enrichment" tables that use coolant temp to decide which table should be implemented yet have a timeframe in which they operate. These tables can monkey with the air fuel ration for quite some time after start-up. We usually either turn the time on these tables down to 10 seconds or just crank the car and let it idle for 30-60-90 seconds before making each pull. Perhaps if we let the Tweecer equipped cars idle for a bit before each pull they would prove more consistant. Oh, by the way, if it makes Sendero and Italian feel any better; the EECTuner on my turbo car began "freaking out" from time to time much like theirs did. It would work well for 2-3 pulls then actually go so lean that the car would not turn over 4000 RPM. I just unplugged the thing and it made its 637 HP and 752 TQ (small turbo)on a stock A9l program with no tuning device at all! If anyone wnats to try the EECTUNER on their car it is for sale.....Perhaps best for a NA combo ;)

Italian LX
01-24-2005, 11:10 AM
. . . perhaps this could be the root of the Tweecer problem we were having on the black Cobra and white coupe. Even though we are monitering AFR @ WOT on the dyno, if the computer is still "counting down" to its CL switch-over point, it may be affecting the AFR on our pulls.
I believe we actually talked about this that day and we had both cars do a couple of back-to-back pulls that would've allowed plenty of time to be out of the "cold start" time parameter.

I haven't exactly found my problem yet, but I just put some 24# injectors in to see if it clears up my low RPM WOT lean condition. So far it looks good, but I haven't gotten the MAF curve dialed in yet for the new injectors.... I guess we'll see how it goes after I get it street tuned.

EZ SPEED
01-24-2005, 12:19 PM
If the transfer to CL is, indeed, time based (though I have always thought it to be switched by coolant temp) perhaps this could be the root of the Tweecer problem we were having on the black Cobra and white coupe.

Remember Blake.....the same thing happened to my 94 Cobra Vert later that day with the TwEECer...you might be on to something.

93Cobra#2771
01-24-2005, 01:05 PM
I think (don't quote me here) that 94+ cars are based on properly heated/switching O2's. In fact, they can switch to CL in a few seconds, from what I understand. I'm a little muddy, though, if that is 94+ or 96+...

The A9L OL to CL uses time as it's final factor. In other words, it won't go any longer than X seconds before the switch, but it doesn't HAVE to go X seconds. It can switch earlier than that...