When does the ECM switch from closed loop to open loop mode? : V-Twin Forum: Harley Davidson Forums

kslg · 02-22-2008, 01:16 PM

I've been searching through threads and can't find this one...

When does the ECM on the 07-08's switch from closed loop to open loop?

I know it is closed loop at idle and cruising; someone told me it stays in closed loop until higher than 50-60% throttle.

When it does switch to open loop, has anyone seen with a sniffer what the AFR goes to? I've heard that it is significantly richer.

I am just doing intake and exhaust and don't want to go to a full programable fuel system. I have seen the voltage splitters from nightrider and was thinking this is all I might need...

HDMD88 · 02-22-2008, 03:15 PM

Quote:

Originally Posted by kslg

I've been searching through threads and can't find this one...

When does the ECM on the 07-08's switch from closed loop to open loop?

I know it is closed loop at idle and cruising; someone told me it stays in closed loop until higher than 50-60% throttle.

When it does switch to open loop, has anyone seen with a sniffer what the AFR goes to? I've heard that it is significantly richer.

I am just doing intake and exhaust and don't want to go to a full programable fuel system. I have seen the voltage splitters from nightrider and was thinking this is all I might need...

Not all Ecm's are programed the same, the heave bikes come out of closed loop a little earlier than a lighter bike. Most bikes go into closed loop at 20KPA and come out of closed loop at 80 to 85 KPA. Now depending if your going up hill or down hill effects the KPA at different throttle positions so to say it comes out at 50~60% throttle would be a false statement at times.
When it does come out of closed loop the AFR is generally 13.5:1 to 12.5:1, again, depending on the load of the engine.

The idle is not in closed loop...the AFR is usually from 13:1 to 13.5:1.

With a Race Tuner we are able to control the switching point.
Raising the voltage on the sensors will make the bike run richer but your putting the sensors on the edge of their learning ability which stress switching operation of the sensor to an earlier failure....when it fails (in about 6000 to 10,000 miles) you are automatically set at at 14.6:1 in every grid of closed loop operation. (this is not good)

langner91 · 02-22-2008, 03:19 PM

There is a slug of parameters that must be satisfied for the bike to go into closed loop mode. Two that I know for sure are:

Throttle position.
Head Temperature. (Too cold or too hot will prevent closed loop.)

I am sure there are other factors too.

When it isn't in closed loop mode the AFR is the result of the map. So, it is incorrect to say that when not in closed loop the bike will run significantly richer because some portions of the map may be nearly as lean as closed loop (close to 14.7:1).

Anyway, I realize that the 14.7:1 area is too lean for most people's liking, but regardless of what you do with A/C and exhaust, closed loop operation will result in an AFR of 14.7:1. Adding a voltage splitter will do nothing for the times the bike is in open loop mode. This is the area that your fuel maps will be too lean (as a result of adding the A/C and exhaust) and the bike cannot compensate for this condition.

If all you are doing is A/C and exhaust, I would recommend the download from the dealer.

kslg · 02-22-2008, 03:49 PM

I was thinking of doing the H-D download- but was also told that the download doesn't richen the map at all, it just raises the redline.

It would think it has to richen the open loop map because it is designed for a free(er) breathing intake and exhaust while running on that map? Does it richen the closed loop as well?

I can't seem to find info on how exactly the download effects the mapping etc.

Being that the H-D download is designed for SE Pipes and intake, would it matter if I did a Doherty intake with a recored factory exhaust?

BTW- I recently got my factory pipes recored, gotta say, they sound great, very deep and a whole lot cheaper than buying a new set of pipes.

langner91 · 02-22-2008, 04:30 PM

You can't richen the closed loop mode (without using the voltage dividers) because closed loop implies the ECM is using the narrow band O2 sensors to adjust the AFR. These sensors will force the bike to 14.7AFR.

I have always believed that the Stage I download is a richer map to accomodate free flowing A/C and exhaust. If it doesn't richen the map, there is no sense in having it. But again, this can only be richer in open loop mode.

kslg · 02-22-2008, 05:13 PM

Doc, you mentioned that the 02 sensors go bad at 6-10k, what are the symptoms- rough idle or weak accel? & What is KPA? I would guess it is a % measurement of engine load?

I would imagine the HD download has to richen the open loop...no other reason to have it like you say.

It would be good if they could make the voltage dividers that created an afr around 13.5. Not a wide enough band I guess.

I might get the voltage thingers because of how hot it gets here in the summertime (Charleston, SC). I would have to believe they would help some.

HDMD88 · 02-22-2008, 07:08 PM

Quote:

Originally Posted by langner91

There is a slug of parameters that must be satisfied for the bike to go into closed loop mode.

Throttle position. Some say up to 50%.
Head Temperature. Too cold or too hot will prevent closed loop.
I am sure there are other factors too.

When it isn't in closed loop mode the AFR is mapped. So, it is not correct to say that when not in closed loop it is significantly richer. Some portions of the map may be nearly as lean as closed loop (14.7:1).

Anyway, I realize that the 14.7:1 area is too lean for most people's liking, but regardless of what you do with A/C and exhaust, the closed loop portion of the bike will be 14.7:1. Adding a voltage splitter will do nothing for the times the bike is in open loop mode. This is the area that your fuel maps will be too lean and the bike cannot compensate for this condition.

If all you are doing is A/C and exhaust, I would recommend the download from the dealer.

All I can say is.....WHAT.....!!!!!.......

HDMD88 · 02-22-2008, 07:22 PM

Quote:

Originally Posted by kslg

Doc, you mentioned that the 02 sensors go bad at 6-10k, what are the symptoms- rough idle or weak accel? & What is KPA? I would guess it is a % measurement of engine load?

I would imagine the HD download has to richen the open loop...no other reason to have it like you say.

It would be good if they could make the voltage dividers that created an afr around 13.5. Not a wide enough band I guess.

I might get the voltage thingers because of how hot it gets here in the summertime (Charleston, SC). I would have to believe they would help some.

The 02 sensor will have a shortened life span if you change the Bias voltage to .798 or using the voltage splitters that do the same thing that the Bias Voltage does in the Race Tuner. It WILL richen the closed loop area to 14.2:1~14.1:1 when the voltage is altered....the down side is when the sensor goes bad the AFR will go to the programed number in the AFR table which is 14.6...(not 14.7). How will you know? You won't unless you test it with a sniffer or realize your engines running hotter than it was. The motor will run fine at 14.6:1.....but it will run hotter.
KPA is a measurement of pressure......one atmosphere is 100 KPA (kilopascals)

WVRDKING · 02-22-2008, 07:27 PM

Quote:

The idle is not in closed loop...the AFR is usually from 13:1 to 13.5:1.

Doc: Hope I'm not misunderstanding the above, but when I first got the SERT I did a Data Recording of Idle characteristics at operating temperature and it was definitely operating in Closed Loop.

Results showed:
1012 RPM
TP: 0%
MAP: 41.0
AFR Desired: 14.6

Checking the map that was loaded showed this MAP/RPM in the CL portion of the AFR Table.

Thanks for your input!

kslg · 02-22-2008, 07:32 PM

How long do the sensors last if you don't change the bias?

You'd figure the check engine light would come on when they crap out.

Anyone know exactly what the H-D download changes besides redline?

HDMD88 · 02-22-2008, 07:57 PM

Quote:

Originally Posted by WVRDKING

Doc: Hope I'm not misunderstanding the above, but when I first got the SERT I did a Data Recording of Idle characteristics at operating temperature and it was definitely operating in Closed Loop.

Results showed:
1012 RPM
TP: 0%
MAP: 41.0
AFR Desired: 14.6

Checking the map that was loaded showed this MAP/RPM in the CL portion of the AFR Table.

Thanks for your input!

Again this depends what map your using, the new 477v with the 176 files has most of the maps at closed loop in the 20 KPA area which would be in the idle area. The first two maps in the 176 files are in open loop and set at 13.0:1~12.5:1. The 462v 159 files had more open loop at 20 KPA than closed loop if my memory serves me right. Bottom line is I should have said some are and some aren't....my mistake

HDMD88 · 02-22-2008, 08:03 PM

Quote:

Originally Posted by kslg

How long do the sensors last if you don't change the bias?

You'd figure the check engine light would come on when they crap out.

Anyone know exactly what the H-D download changes besides redline?

Stage one richen the fuel by 5% all the way through the map plus red line goes to 6200 rpm.

There are too many variables that will determine sensor life...Gas additives, exhaust leaks, bad valve seals, on and on

claydbal · 02-22-2008, 08:26 PM

Quote:

Originally Posted by HDMD88

Stage one richen the fuel by 5% all the way through the map plus red line goes to 6200 rpm.

There are too many variables that will determine sensor life...Gas additives, exhaust leaks, bad valve seals, on and on

doc, you knowv i espect you and your answers are un debateable. i have tio ask--if a sensor is off and closed loop depends on that false info, wouldnt the ecm feed eronious info? maybe the factory o2 sensor senses a rich mix and leans to compensate-------------equals fried piston?

Bingo · 02-22-2008, 08:57 PM

More confusion.

I read so many posts that recommended the clb table be maxed out at .798 so that's what I did to my 08 RG.

This is not a good thing? So I really don't know how to richen the mix for a SE air cleaner and true dual's?

ToBeFrank · 02-22-2008, 08:59 PM

Quote:

Originally Posted by HDMD88

The 02 sensor will have a shortened life span if you change the Bias voltage to .798 or using the voltage splitters that do the same thing that the Bias Voltage does in the Race Tuner. It WILL richen the closed loop area to 14.2:1~14.1:1 when the voltage is altered.

So you're saying the sensors have a shortened life because there is less oxygen in the exhaust? Not saying you're wrong, but I don't understand this. If that's true, the sensors would always have a shorter life because the open loop areas are richer.