Throttle response hesitation ? Brown wire ?

[Frenchy]

Hi

Sorry for the thread. It seems the subject already has been discussed but I'm not sure...

My '99 sometimes shows hesitation under high weather temperature (above 20°c). :( Not all the time but it's quite disturbing. Is this linked with the brown wire in any way ???

Thanks for the help :rolleyes:

[UncleRock]

Hi

Sorry for the thread. It seems the subject already has been discussed but I'm not sure...

My '99 sometimes shows hesitation under high weather temperature (above 20°c). :( Not all the time but it's quite disturbing. Is this linked with the brown wire in any way ???

Thanks for the help :rolleyes:
If you are talking about what seems like a little hitch before the engine responds. Feels Like a little extra slack in the cable, no that is not a Brown Wire issue.
I have a 99 and because I count on the bikes power to deliver me out of harms way 100-1 over the brakes, I'm very sensitive to it.
I had this same issue going on and talked with Craig (Master Tech), we covered it all, including his riding the bike.
You can get some cable stretch, if you ride hard, it can be adjusted.
You can't take all of the slack out, you need room for the forward snap to shut off the cruise.
Rock :D

[bustedknuckles]

Hi

Sorry for the thread. It seems the subject already has been discussed but I'm not sure...

My '99 sometimes shows hesitation under high weather temperature (above 20°c). :( Not all the time but it's quite disturbing. Is this linked with the brown wire in any way ???

Thanks for the help :rolleyes:

It has been a while since working on a pre "brown wire" model. Your 99 model does NOT have the brown wire. The 99 model has something that look like a relay which is under the top box (it was yellow on the one I remember removing). Removing that relay did the same thing as cutting the wire on later models. The brown wire was not introduced until the "01" model year.

[Frenchy]

It has been a while since working on a pre "brown wire" model. Your 99 model does NOT have the brown wire. The 99 model has something that look like a relay which is under the top box (it was yellow on the one I remember removing). Removing that relay did the same thing as cutting the wire on later models. The brown wire was not introduced until the "01" model year.

Thanks but can you explain the use of the stuff : brown wire or relay... I'm not sure I understand the link with some throttle hesitation :eek:

[dshealey]

It has been a while since working on a pre "brown wire" model. Your 99 model does NOT have the brown wire. The 99 model has something that look like a relay which is under the top box (it was yellow on the one I remember removing). Removing that relay did the same thing as cutting the wire on later models. The brown wire was not introduced until the "01" model year.

Removing the "Cat code plug", the yellow box under the top case, can only be done if the motronic has been updated to the later version with the dual fuel injection mapping. If it is removed on the earlier version Motronic the hesitation will not change, but you will have other problems.

The new Motronic was not put in bikes until mid 2000 manuf. date. My '01 had the new motronic, and still had the cat code plug, which the dealer pulled to stop the hesitation. In '01 the wiring harness was changed to eliminate the cat code plug and incorporate the brown wire loop instead. The cat code plug was nothing but a jumper to connect one pin of the motronic to ground, they just re-routed the wire to a loop that can be cut.

On a '99-'01 LT without the correct motronic (dealer can check it with the moditec to see which version it is) unless the motronic is changed out the only other way to elleviate the hesitation is to unplug the air box temp. sensor (right behind the radiator cap) and then always use premium fuel in warm temps.

[alindsay]

You are correct, it does look like a relay but is just a plug (yellow or orange) located on the left side under the cover under the top box. You will, however, need to check which Motronic control unit you have as the early ones did not have the dual map that is activated by removing the plug. Many '99's had the Motronic replaced but only your dealer can tell. I believe there are instuctions in the HOW on what to look for.

If you have the correct Motronic control unit, pull the plug and don't look back. My '01 had the (it is called the CAT Code Plug) with the dual map Motronic. Made a big difference. No more hesistation.

[Frenchy]

If you are talking about what seems like a little hitch before the engine responds. Feels Like a little extra slack in the cable, no that is not a Brown Wire issue.
I have a 99 and because I count on the bikes power to deliver me out of harms way 100-1 over the brakes, I'm very sensitive to it.
I had this same issue going on and talked with Craig (Master Tech), we covered it all, including his riding the bike.
You can get some cable stretch, if you ride hard, it can be adjusted.
You can't take all of the slack out, you need room for the forward snap to shut off the cruise.
Rock :D

Thanks Rock

But wouldn't a cable issue do the trick all the time ?

[mneblett]

If you are talking about what seems like a little hitch before the engine responds. Feels Like a little extra slack in the cable, no that is not a Brown Wire issue.
I have a 99 and because I count on the bikes power to deliver me out of harms way 100-1 over the brakes, I'm very sensitive to it.
I had this same issue going on and talked with Craig (Master Tech), we covered it all, including his riding the bike.
You can get some cable stretch, if you ride hard, it can be adjusted.
You can't take all of the slack out, you need room for the forward snap to shut off the cruise.
Rock :DSorry, Rock -- gotta disagree; Frenchy has *precisely* described the symptoms of the over-20C ignition retard that the alternate fuel mapping cures. If he had the same issue at all temps, and he could feel a glitch in the cables, I might be with ya -- but if he adds that the problem only occurs when the rpms are fairly low when he opens the throttle, then it's definitely the Moronic programming. A new Moronic (or verifying the current Moronic has been upgraded) and removal of the yellow plug under the trunk, and the issue's gone.

[Frenchy]

Sorry, Rock -- gotta disagree; Frenchy has *precisely* described the symptoms of the over-20C ignition retard that the alternate fuel mapping cures. If he had the same issue at all temps, and he could feel a glitch in the cables, I might be with ya -- but if he adds that the problem only occurs when the rpms are fairly low when he opens the throttle, then it's definitely the Moronic programming. A new Moronic (or verifying the current Moronic has been upgraded) and removal the yellow plug under the trunk, and the issue's gone.

Well, guess that's my case :D
I'll have the dealer confirm the Motronic version first.

THANKS EVERYONE

:bmw:

[UncleRock]

Sorry, Rock -- gotta disagree; Frenchy has *precisely* described the symptoms of the over-20C ignition retard that the alternate fuel mapping cures. If he had the same issue at all temps, and he could feel a glitch in the cables, I might be with ya -- but if he adds that the problem only occurs when the rpms are fairly low when he opens the throttle, then it's definitely the Moronic programming. A new Moronic (or verifying the current Moronic has been upgraded) and removal of the yellow plug under the trunk, and the issue's gone.
I understand all that, this is why I decribed what was happening, and IF that was the case.
What the hell is 20C?
Rock

[mneblett]

I understand all that, this is why I decribed what was happening, and IF that was the case.
What the hell is 20C?
RockOkey-dokey -- I'll assume I just misread your "if" part :) 20C=20 degrees celcius (86 degrees F).

[midwilshire]

Removing the "Cat code plug", the yellow box under the top case, can only be done if the motronic has been updated to the later version with the dual fuel injection mapping. If it is removed on the earlier version Motronic the hesitation will not change, but you will have other problems.

The new Motronic was not put in bikes until mid 2000 manuf. date. My '01 had the new motronic, and still had the cat code plug, which the dealer pulled to stop the hesitation. In '01 the wiring harness was changed to eliminate the cat code plug and incorporate the brown wire loop instead. The cat code plug was nothing but a jumper to connect one pin of the motronic to ground, they just re-routed the wire to a loop that can be cut.

On a '99-'01 LT without the correct motronic (dealer can check it with the moditec to see which version it is) unless the motronic is changed out the only other way to elleviate the hesitation is to unplug the air box temp. sensor (right behind the radiator cap) and then always use premium fuel in warm temps.

How you guys figure all this stuff out is beyond me. I guess that is why I visit this site!

[dshealey]

How you guys figure all this stuff out is beyond me. I guess that is why I visit this site!

Some of us have been here "forever", and have collectively taken all our learned things and put them together. All these little tidbits have been gleaned from many, many inputs from a lot of sources over the years.

[dadler]

OK, I did it!!!! And I did NOT hear, understand, etc what my friend David Shealey said.
I unplugged the air temp sensor, I pulled the Cat code plug, and just got worse. Did you understand that I had to check the motronic mapping program. Of course, it was the original, not the ungraded one. When I had work at the dealers, the air sensor plug was plugged in again. Still hesitation whenever and wherever I would start from the dead start.

Soooooooooo......... I reread what was said. I have now unplugged the air temp sensor again, BUT cannot find the Vat code plug. So if anyone has one on the shelf, may I have it?

Please call me 630-849-9055 and we will make arrangements. The bike is apart waiting for the final issue. Thanks again.

David Adler
Aurora, IL

[Buckelew]

David, tell your dealer you have a hesitatin problem when it's hot; ask him to check the motronic version. there is an unofficial program to swap out computers of certain bike years with re-chipped ones. You don't need to unplug anything after that, but you will need to run the good gas. High octane.

My bike was built in July 2001; no brown wire, no cat code plug. I unplugged the air temp sensor and it ran fine on high octane - pinged on low octane. brought it into the dealer and showed them that I unplugged the air temp sensor and it ran fine, but hesitated toherwise when it was hot. They put me on "the list". About a month or 6 weeks later, I got a call and they installed the new motronic computer and it's run fine since then.

[dadler]

I guess I am on the way to the dealer. Thanks, loads. Will stop tomorrow.
David

[dshealey]

OK, I did it!!!! And I did NOT hear, understand, etc what my friend David Shealey said.
I unplugged the air temp sensor, I pulled the Cat code plug, and just got worse. Did you understand that I had to check the motronic mapping program. Of course, it was the original, not the ungraded one. When I had work at the dealers, the air sensor plug was plugged in again. Still hesitation whenever and wherever I would start from the dead start.

Soooooooooo......... I reread what was said. I have now unplugged the air temp sensor again, BUT cannot find the Vat code plug. So if anyone has one on the shelf, may I have it?

Please call me 630-849-9055 and we will make arrangements. The bike is apart waiting for the final issue. Thanks again.

David Adler
Aurora, IL]

David,
Unplugging both the Cat code plug AND the air temp sensor at the same time is a BAD thing to do. I think that may have contributed to my piston damage when I had the mis-diagnosed vacuum leak in Little Rock.

[dshealey]

---------- BUT cannot find the Vat code plug. So if anyone has one on the shelf, may I have it?
David Adler
Aurora, IL

I think I still have the one the dealer removed from my bike. I will look for it when I get home tonight.

[mauricedorris]

I had this exact same problem last year. Only on a warm day, with the engine temp a little high, but not overheating, I'd turn the throttle and NOTHING. The bike didn't move.

Then all of a sudden, it would kick in and I'd have to hold on. At the scariest times, I'd be on the freeway, doing about 20-30 mph is slow moving traffic. I would try to speed up to change lanes and it would hesitate.

I thought it was pretty dangerous and took the bike in to BMW of Hollywood. They didn't find anything the first time, because it was a cool day. Then I told the mechanic to "heat it up" and try again.

What he found was that there was some electronic components that monitor the throttle position so the EFI would know how much more fuel/air to give it. I think he said it was the "throttle potentiometer".

He changed it, and the problem went away. You would not find this particular hesitation unless it is hot outside and you are moving at a slow-medium speed and then you try to accelerate. However, it was very real.

I hope this helps.

[dadler]

Thanks David

Talking to the regional service mgr about upgrading the mapping program but his knowledge of the hesitation issue is skimpy at best. He will try to negotiate a price for me but I expect that will be over the dealers cost, etc.

I thought I saved the Cat code plug but in moving, cannot find it. If you still have one, I would appreciate your generosity and I will repay your expenses, etc.

David

[dshealey]

I found it!

If you want it sent, PM your address.

[unleashd]

Hmm...I think I am also in the same boat. Just posted a new thread to this effect also!

[NRuest]

I know this is an old thread but it is one of the threads that helped me. And I wanted to post my experience so... here goes.

I have a 2000 and my motronic has a '99 date so I do not have the alternate mapping. The hesitation has been driving me crazy so last week I finally pulled the temp sensor. OMG. What a huge difference it made. This bike has never run so smoothly and has not hesitated even slightly.

I was concerned about the gas mileage thinking that it was probably running a little richer than it had been but so far it seems that my gas mileage may have even improved. I have only run one tank through so far and am ready to fill it again but I got 42 mpg (up from 39-40).

I had to let everyone know how much of a difference disconnecting the temp sensor made for me. Don't know why I waited so long.

[KIC]

Earlier in this thread this statement was made:

"..there is an unofficial program to swap out computers of certain bike years with re-chipped ones. "

Does anyone know more details as to the years, VIN numbers or any way of identifying which bikes might fall under this? :confused:

[gglove]

I have complained about this very thing on several occasions to the dealer to no avail. I have been told numerus times there is nothing wrong and that it is normal. It is way to cold to test it out now. When the weather breaks in a few months I will call upon your advise, because my memory sucks!
Damn brown wire :D