O2 Sensor, Laser chip and a fast idle.
 

I have discussed a problem previously with my BCR and the intermittent high idle speed.

The basics are that every now and again the idle speed goes up to 2000 rpm and then returns to normal after a few minutes/miles. I am also getting a lot of popping when I roll of the throttle.

I have recently changed out the catalytic converter and fitted a Laser Y- piece (with Lambda sensor fitted) and also installed a K&N air filter.

Today I took the bike to the only BMW dealer on island and had it hooked up to the computer. All was well apart from the O2 Sensor which was swinging above and below the recommended parameters. On the screen the sine wave generated was very cyclic and repeated itself. The dealer suggested I take the bike to their main workshop for some more tests on the O2 sensor as the computer instructed - marvellous this technology thing.

Could this be the cause of my problem of the increased idle speed?

I have also just purchased a Laser power chip. Should I wait and just install the chip as I believe it dispenses with the O2 sensor.

Your thoughts would be greatly appreciated as I am running out of hair to pull out.

Cheers

Derek

Well,

IF (IF) that chip dispenses with the Sensor, and IF that is the problem, then it's an easy choice.

I'd prefer to definitively solve the problem before throwing other parts at it. Is synch good, not only the cable, but the air bypass screws?

A sensor's job is just to report/sense. The normal failure mode for the actual sensor would show smaller, not larger, than normal swings. However, a loose or damaged, high resistance connection can show a slightly higher output than normal. To know, we have to quantify what your diagnoser means? Higher than the normal control-limit parameters? Or higher than the normal sensor swing (O-1V, in rough numbers)

Are we absolutely sure the throttle doesn't ever hang?

laser chip still wants the sensor. probably don't need the chip with just the cat elim pipe. in general, the chip richens the mix.

Delpel,
had the same problem for about a day. checked the current to the left cable stop. and found that it was off. set it correctly,(and did not mess with the TPS (0=0) which voids warranty), and then tuned the bike and it works great.
if you need the proceedure just ask and I will send you the links
CYA
Jeff

had a similar sympton immediately after chip install..during 600 mile service, the tech adjusted the idle and all was good...that was 7000 miles ago.

i will say this, the laser chip does seem to make the idle wander a bit, but not a bad thing. it is predictable and consistent so i dont think it is a big thing. i found after each session on the track, it responded better at take off with the fast idle engaged but when doing regular street riding sits at a 1100 rpm just fine. just an observation.

repoe3

The readings the O2 sensor was giving were uniformily above and below the dotted lines on the BMW diagnostic screen (200mV to 650mV) The sinusodila wave was repeating itself over an over and the wave pattern was smooth although not a perfect sine wave.

In my mind if the sensor was breaking down or U/S then the wave would be erratic.

Jeff I would be interested in procedure you mentioned.

I will start to log the occurances and see if they repeat themselves sfter short trips, fast acceleration etc.

The other option is to put the original parts back on one at atime and see if that helps. But then I would lose that lovely Ducati type exhaust note.

If only it would just do it all the bloody time I stand a better chance of pinning it down.

Cheers for the help

Derek

Delpel,
this clip is taken from: http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/157787-throttle-body-synch-question.html
hope this helps
jeff
had the same problem with my bike. I found that the problem was the left throttle body stop. The easiest way to check this is to get a volt metter and check the current of the left throttle stop. The reason you may not be able to get the idle down is that the current is to high which equals the left throttle opened to much from the start. The left throttle cable stop is what you base your tuning upon and what the motronic uses as the base line. YOU DO NOT HAVE TO MESS WITH THE TPS! no 0=0! look at these sites. Site 1 gives the basics. Site 2 shows you an easy way to get to the current. Site 3 is a more detailed version of Site 1. I pulled step #10 from Site 3 and will hope full help. Remember you donot have to mess with the TPS, just use the tuning steps after that.
BTW my bike runs much better after I did this. if you check on of the sites on the ibmw.org/tech about tuning it says that you can change (to a certain extent) the power on the top end, make it run rich or lean, lessen surge and vibration at different rpm. Thats beyond me I just know what worked on my bike.
cya
jeff
ps will be going thru your area on thursday afternoon. lets hook up.
jw

http://www.ibmwr.org/r-tech/oilheads/zero528.shtml

http://www.ibmwr.org/r-tech/oilhead...vom/index.shtml


http://www.ibmwr.org/r-tech/oilheads/t-screw.shtml
Step 10. Reduce TPS in increments of 0.020 if idle exceeds 1100-1200 rpm After adjusting the right side throttle plate screw to get equal mercury columns, look at the rpm. Ideally, rpm is now 1100 to 1200. Some bikes will have an abnormally high idle; as high as 1800 rpm or more. This is most prevalent in GS and R models. To correct the high idle, return to Step 6 and place one lead of the digital volt meter (DVM) back on the red and white wire of the TPS and ground the other lead. DO NOT move the Bosch black TPS. Reset the left throttle plate screw (the left rear screw with lock nut that was difficult to adjust) and reduce the TPS voltage by 0.020 volts (from .370 to .350) by turning the throttle plate screw. Continue with the rest of the Steps in order after Step 6. If the idle is still too high, continue to reduce the TPS value by increments of 0.020 until the desired idle is reached


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Well, I couldn't resist checking my TPS settings. Here is what it was set at:

Idle Setting = 355 mv
Zero setting = 2.4 mv

This sounds like it should be ok, so I just put the LH throttle stop back to the 355 mv setting. It doesn't seem that these settings would lead to an unusually high idle, so I didn't change the TPS Zero adjustment and called it a day. The bike actually runs fine now except for the 1250 rpm idle, with the bypass screws at a little under 1 turn each. I think I'll just put some miles on it and see if it settles down. If someone thinks it would help smooth things out if my TPS settings were changed to the zer0 = 10 mv and 370mv or so Idle, let me know. It's easy enough to go back and tweak it a bit, but I just don't see how it would make that much difference.


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Scott
Ok, well that plan to leave the TPS alone lasted about an hour. I got to thinking if it isn't running quite right and it is slightly off, then just do the whole TPS/Throttle Body adjustment procedure from the start. I basically followed what Micky was trying to tell me and the article that Jeff linked to me from IBMWR, http://www.ibmwr.org/r-tech/oilheads/zero528.shtml . Simple enough to do and best of all it works beautifully now. The idles settles in quickly to 1100 rpm with both bypass screws at 1-1/4 turns each, no surging, quick response and smooth transitions between on and off throttle. Whew, that's better. Glad I just went ahead and did what I knew I had to do in the first place.

Hey Jeff;

Where did you set the idle at 355mv?

EZ,
I set mine at 360mv

BTW, be careful of the screw for the throttle stop. it will strip easily and their is not part # on the cd for it,(personal experience). What little I could find the bolt and nut could cost as much as $6.00. Very expensive
jeff

Hmmm....
 

Greetings Delpel,

The 02 sensor MUST be functional and installed for the LASER PowerChip's programming to effect a positive change.

Sounds like a confused motronic. Are the throttle bodies, cables and engine (valves, plugs and such) in sync/proper tune?

Going to the TPS settings is a big step and should not be done until the above is assured.

Please feel free to contact me by phone regarding your issues.

Cheers for that Robert and everybody else.

I took the bike for a nice long and may I say hard ride yesterday and suffered no re-occurance of my fast idle problem. The BMW tech has checked everything and reset the idle and TB sync although the sync wasn't out. He also found one of the rubber take off caps for the sync machine was split so he replaced that. All seems well, it is idling at just over 1100 rpm. I will keep an eye on things and take notes (where, when) if it happens again.

The power chip is on it's way from the US of A, won it on ebay. Just waiting for the packet to drop through my letter box.

Again cheers everybody. I shall stop being so paranoid now.

TTFN

Derek