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post #1 of 131 Old Jul 23rd, 2009, 6:23 pm Thread Starter
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Electrical Help Needed

My bike is running so bad it starts to foul a new set of plugs in less than 50 miles. the fuel milage has gone from the low 50s mpg to the mid 20s mpg. It had been at the dealer for almost six weeks & they are stumped. I just can't give them a blank check & have them fix it.

The only fault code is the O2 sensor. 2 different sensors have been installed & both still showed a fault code. They also checked the injectors for leakage. They changed the Motronic control unit & Ign. coil. Nothing helped. The way the bike runs its more than just dumping to much fuel. It barley has enough power to get going from a stop light.

I do have have a good Digital Multimeter but I'm not very good with electronics. The mechanical part of the engine (valve lash,compression test & leak down) is the same as it has been for the last 30,000 miles.

If there is any interest in the Charlotte NC area for a tech session I would be more than happy to have one. I have plenty of space & all the tools that would be needed.

Any thoughts: Thanks Dave

Dave Selvig
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post #2 of 131 Old Jul 23rd, 2009, 6:34 pm
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Re: Electrical Help Needed

Engine temperature sensor?

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post #3 of 131 Old Jul 23rd, 2009, 7:31 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by mobygrape
Engine temperature sensor?
It runs the same hot or cold. It also started out as a intermittent problem but now is a full time problem

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post #4 of 131 Old Jul 23rd, 2009, 7:53 pm
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Re: Electrical Help Needed

Fuel pressure regulator? Too much fuel spraying through the injectors may cause the 02 sensor to be confused.
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post #5 of 131 Old Jul 23rd, 2009, 9:41 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by pushin9s
Fuel pressure regulator? Too much fuel spraying through the injectors may cause the 02 sensor to be confused.
When I checked the fuel pressure it was 65 to 80 lbs & that was the first thing I changed. At first first I was sure that was the problem. With the new regulator it is now a steady 50psi.

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post #6 of 131 Old Jul 23rd, 2009, 10:13 pm
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Re: Electrical Help Needed

You say two O2 sensors have been installed and they both read faults? Get out your meter and check that there is 12V at pin 1 of the connector (should be green/white on the bike side harness) This is fed from the fuel pump relay so the bike should be running when you test it.

The only other thing is to check continuity from the O2 sensor connector to the Motronic. Sounds like everything else has been eliminated.

pin 1 Green/White fed 12v by Fuel pump Relay
pin 2 Green/Brown to pin 25 at Motronic
pin 3 Yellow to pin 12 at Motronic
pin 4 Black to pin 11 at Motronic.

Note: the last two are also sheilded.

Good luck.

John
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post #7 of 131 Old Jul 24th, 2009, 11:38 am
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Re: Electrical Help Needed

If the engine temp sensor is bad, it can produce the extreme rich condition that you describe. It won't matter if the bike is hot or cold, it will be way to rich to run in any condition. The O2 sensor problem might cause poor milage, but not the plug fouling and driveablity problems that you describe. I had an oilhead that had an intermittent excessive richness fault. It would go from running fine to barely able to make it home. It was the engine temp sensor.

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post #8 of 131 Old Jul 24th, 2009, 1:25 pm
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Re: Electrical Help Needed

Good point Paul. It is the one on the rear of the cylinder head.

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post #9 of 131 Old Jul 24th, 2009, 4:33 pm
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Re: Electrical Help Needed

I would think that if two O2 sensors are showing a fault code in the computer then there is a good chance of a short circuit or open circuit in the wiring harness between the O2 sensor and computer. This would cause a full rich condition.


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post #10 of 131 Old Jul 24th, 2009, 5:16 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by mobygrape
If the engine temp sensor is bad, it can produce the extreme rich condition that you describe. It won't matter if the bike is hot or cold, it will be way to rich to run in any condition. The O2 sensor problem might cause poor milage, but not the plug fouling and driveablity problems that you describe. I had an oilhead that had an intermittent excessive richness fault. It would go from running fine to barely able to make it home. It was the engine temp sensor.
If the engine temp sensor is bad would the temp gauge still work properly?. It is running worse than just a open loop O2 sensor.

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post #11 of 131 Old Jul 24th, 2009, 5:36 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by jzeiler
You say two O2 sensors have been installed and they both read faults? Get out your meter and check that there is 12V at pin 1 of the connector (should be green/white on the bike side harness) This is fed from the fuel pump relay so the bike should be running when you test it.

The only other thing is to check continuity from the O2 sensor connector to the Motronic. Sounds like everything else has been eliminated.

pin 1 Green/White fed 12v by Fuel pump Relay
pin 2 Green/Brown to pin 25 at Motronic
pin 3 Yellow to pin 12 at Motronic
pin 4 Black to pin 11 at Motronic.

Note: the last two are also sheilded.

Good luck.
I will check the voltage as soon as I get the tank back on. My wiring diagram doesn't show where the volts come from. I still need to remove the upper fairing. I want to be able to look at the whole wiring harness. There is visible signs of salt spray from riding this past winter under the gas tank.

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post #12 of 131 Old Jul 24th, 2009, 11:29 pm
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
If the engine temp sensor is bad would the temp gauge still work properly?. It is running worse than just a open loop O2 sensor.
There are two temp sensors. The one that feeds the guage is on the water pump, the one that feeds the Motronic brain is on the back side of the cylinder head near the coil pack.

John
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post #13 of 131 Old Jul 25th, 2009, 7:20 am
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Lightbulb Re: Electrical Help Needed

I had a similar problem and the falt was due to a defective Throttle Valve Stub . The shop manual refers to this as the Throttle valve potentiometer.
This does not support the prior DX code of faulty O2 sensor, Just some food for thought.

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post #14 of 131 Old Jul 25th, 2009, 9:13 am Thread Starter
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Re: Electrical Help Needed

The continuity of the O2 sensor checks out on the three wires to the computer. The green-white wire has 13.72 volts when running.
On the engine temp sensor is it possible to put it in a pot of water & bring it to a boil while checking the ohms?.

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post #15 of 131 Old Jul 25th, 2009, 11:48 am
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Re: Electrical Help Needed

You could but there is no data available on what the correct readings should be. If it is working I would expect a change in reading as the temp increases. If you don't get a change I would say it is bad.

I would say just change it but it, like every thing else, is an $80.00 part.

Also since the cable is relativley short you may be able to just disconnect it and see if there is a difference in the performance.
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post #16 of 131 Old Jul 25th, 2009, 1:16 pm Thread Starter
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Re: Electrical Help Needed

I just checked the engine temp sensor with the engine cold. On the 4k scale it reads 1.993 & on the 4m scale it reads .002. I said I have a nice Digital Multimeter but I didn't say I know how to use it. Not knowing wich scale to use I'll check both.

I just put another set of spark plugs in they shouldn't foul near as quick with no load. I'll run the engine at a fast idle & watch the ohm meter on the engine temp sensor as the engine heats up. I'm not ready to just throw parts at it yet.

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post #17 of 131 Old Jul 25th, 2009, 1:58 pm
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Re: Electrical Help Needed

I had a 2000LT that did the same thing. Limped into the dealer. The dealer had the bike for 16 weeks and could find nothing diagnosable. BMWNA was no help. Finally replaced the Motronic unit. This fixed the problem for a short while. I finally tore into the bike and found a number of electrical connections showing corosion. I cleaned them up and gave them a coat of di-electric grease. This permanently solved my problem. Hope this helps.
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post #18 of 131 Old Jul 25th, 2009, 2:13 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by cbrxman
I had a 2000LT that did the same thing. Limped into the dealer. The dealer had the bike for 16 weeks and could find nothing diagnosable. BMWNA was no help. Finally replaced the Motronic unit. This fixed the problem for a short while. I finally tore into the bike and found a number of electrical connections showing corosion. I cleaned them up and gave them a coat of di-electric grease. This permanently solved my problem. Hope this helps.
Chris
The dealer tried a motronic with no help. The only corrosion I have found so far was with the BC computer connections which the mechanic said was normal. That has been unhooked for the last 2000 miles. I have my radar detector in its place.

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post #19 of 131 Old Jul 25th, 2009, 2:26 pm Thread Starter
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Cool Re: Electrical Help Needed

It won't run but for a few seconds with the engine temp sensor unhooked. I just hooked the temp sensor back up & ran it until the water temp reached 220 at the radiator thats when the fans kicked in. The 4k reading cold was 1.993 at 220 its at .170. The 4m reading cold was .002 at 220 its at .000.

For its worth I also checked the exhaust temps at the header flange. #1 490, #2 406, #3 350, #4 350

I'm leaning towards the temp sensor is ok.

Now that the bike is to hot to work on I'm headed out back to my 32,000 acre heated swimming hole for a dip.

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post #20 of 131 Old Jul 25th, 2009, 5:30 pm
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Re: Electrical Help Needed

I have to agree the sensor sounds fine. This is going to be a tought one but I'll hang in there with ya on it.

John
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post #21 of 131 Old Jul 25th, 2009, 9:50 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by jzeiler
I have to agree the sensor sounds fine. This is going to be a tought one but I'll hang in there with ya on it.
Thanks John at least its been long enough that I'm through the withdraw systems of not ridding the bike. I was hoping to stop by for one day at CCR on a trip out west that week but I'm not sure even after its fixed I'll take a trip that far for awhile.

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post #22 of 131 Old Jul 26th, 2009, 4:36 am Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by cbrxman
I had a 2000LT that did the same thing. Limped into the dealer. The dealer had the bike for 16 weeks and could find nothing diagnosable. BMWNA was no help. Finally replaced the Motronic unit. This fixed the problem for a short while. I finally tore into the bike and found a number of electrical connections showing corosion. I cleaned them up and gave them a coat of di-electric grease. This permanently solved my problem. Hope this helps.
Chris
Thanks Chris do you remember which connections had corrosion on them. It did start out as a intermittent problem at first.

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post #23 of 131 Old Jul 26th, 2009, 10:22 am
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Re: Electrical Help Needed

I don't know if I'd agree that the sensor is fine.

It seems that depending on which scale you are using, it is going from 1 ohm to 0 ohms, or 0.17 ohms to 0 ohms. That is an insignificant change where current or a digital signal (open or infinite ohms to 0 ohms) is concerned. If it feeds the motronic, then it is probably an open/ short condition (digital signal) that is sent.

Of course, corrosion bridged across connections could cause a short all the time. I would trace back the connections from the sensor and clean/ replace them first.

If you end up back at the sensor, I'd say you need to know what the sensor is expected to do in hot/ cold conditions. The fact that it had an effect when you pulled it could be significant.

Good luck!

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post #24 of 131 Old Jul 26th, 2009, 11:45 am Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by NCrider
I don't know if I'd agree that the sensor is fine.

It seems that depending on which scale you are using, it is going from 1 ohm to 0 ohms, or 0.17 ohms to 0 ohms. That is an insignificant change where current or a digital signal (open or infinite ohms to 0 ohms) is concerned. If it feeds the motronic, then it is probably an open/ short condition (digital signal) that is sent.

Of course, corrosion bridged across connections could cause a short all the time. I would trace back the connections from the sensor and clean/ replace them first.

If you end up back at the sensor, I'd say you need to know what the sensor is expected to do in hot/ cold conditions. The fact that it had an effect when you pulled it could be significant.

Good luck!
With the engine temp sensor unplugged when you turn the key on the fans come on & it will only run for a few seconds. The plug is accessible by just lifting the seat. Maybe someone could check theres cold & hot.
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post #25 of 131 Old Jul 26th, 2009, 7:56 pm
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
It won't run but for a few seconds with the engine temp sensor unhooked. I just hooked the temp sensor back up & ran it until the water temp reached 220 at the radiator thats when the fans kicked in. The 4k reading cold was 1.993 at 220 its at .170. The 4m reading cold was .002 at 220 its at .000.

OK, let me see if I can help you guys out with the electrical readings.... The 4K reading means that the maximum reading is 4.0 K ohms before the meter overloads and you need to move to the next higher scale. The next higher scale sounds like it is 4 Mega-ohms.....a difference of 1000x.

So, your reading on the 4k setting indicates a reading of roughly 2000 ohms when the temp of the water is cold. The reading when hot is only 170 ohms. The sensor should be good.

Now, I've done some work on my Honda Accord and I know that some sensors are current regulators and some act as voltage regulators. I have no idea which type of sensor the temp sensor is on the K120LT but I would guess that it is a current regulator since there is a huge change in the resistance over the temperature range....but I could be wrong. Just the fact that the bike does not run for more than a few seconds without the sensor indicates that the sensor is most likely conducting properly and the fact that the fans come on when the temp gauge hits red line indicates that the sensor is most likely operating within it's intended range.

I am curious as to which temp sensor was checked. I also think that you may be onto something with the exhaust temps. With the first cylinder running so much hotter than the others, doesn't that indicate that the other three cylinders are running much richer?

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post #26 of 131 Old Jul 26th, 2009, 8:40 pm Thread Starter
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Re: Electrical Help Needed

Thanks Chad: The sensor I checked is at the back of the cyl. head that sends its signal to the computer. The sensor at the water pump sends the signal to the temp gage. The only other vehicle I have with a two pole temp sensor is my 1986 Trans-Am. At 85 degrees cold it reads 2.260 compared to the LT @ 1.993. At 220 degrees it reads .123 compared to the LT @ .170. whatever that means.

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post #27 of 131 Old Jul 26th, 2009, 9:05 pm Thread Starter
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Re: Electrical Help Needed

I have just about finished cleaning & using Dielectric Grease on the round type connectors. I did the easy connectors first because I have the right size stainless steel brush to clean the female ends. On the male ends I'm using a spray cleaner & compressed air. Most of these connectors are for accessories but I intend to clean every connector on the bike.
Next I will clean the flat connectors which is more time consuming & they are the more important ones.
So far I have not seen any unusual corrosion. I am also putting a yellow paint dot on the connector when I'm done with it.
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post #28 of 131 Old Jul 26th, 2009, 9:40 pm
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Re: Electrical Help Needed

Hey Dave, I've been reviewing your entire saga from your initial posts when you were in Vermont. It sounds like the main issue started with a bad fuel pressure regulator. Now, I'm not much of a mechanic and I don't claim to know the inner workings of fuel injectors, but is it possible that the high fuel pressure may have ruined 3 of your injectors. I'm looking through my manual and I can't tell if injector one is at the end of the line, but if it is, it would explain why it may be good and the others may be bad. You could take out the first injector and swap it with the fourth injector and see if your temps change on the exhaust outputs. It may help pinpoint an issue that's fuel injector related.

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post #29 of 131 Old Jul 27th, 2009, 1:38 am
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
Thanks Chad: The sensor I checked is at the back of the cyl. head that sends its signal to the computer. The sensor at the water pump sends the signal to the temp gage. The only other vehicle I have with a two pole temp sensor is my 1986 Trans-Am. At 85 degrees cold it reads 2.260 compared to the LT @ 1.993. At 220 degrees it reads .123 compared to the LT @ .170. whatever that means.
Your CTS (coolant temp sensor) sounds just fine. Comparing it to your T/A's readings was a good idea as these appear to be the same style of sensor.
As mentioned above, it seems it may be down to the injectors. The mechanic tested them for leakage butthat is only one small part of the tests needed for a complete checkout.
Ihe best test is called an "injector balance check". You need a special test box to perform this and unfortunately they are hard to come by cheaply. If you were close to me I'd bring mine over to you and run the test.
Essentially what you do is hook up the tester to an injector and to your battery. The tester fires the injector for a predetermined amount of time. You hook up a fuel pressure gauge and prime the pump, record the pressure and then fire the injector. After it has fired you record the pressure. Do this with all 4 injectors and compare pressure readings. This will pinpoint a partially plugged injector, an injector that is flowing too much or a set of injectors that are just not closley matched enough.
Also, if you do the test with the injectors out of the engine you can verify the spray pattern.

One other thing to check for, a severely restricted air tract. Since the LT's fuel injection is "Alpha-N" based it doesn't have any kind of air meter. It sets up fuel delivery based on throttle position (checked this sensor?), O2 feedback and engine temp.
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post #30 of 131 Old Jul 27th, 2009, 7:34 am
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
My bike is running so bad it starts to foul a new set of plugs in less than 50 miles. the fuel milage has gone from the low 50s mpg to the mid 20s mpg. It had been at the dealer for almost six weeks & they are stumped. I just can't give them a blank check & have them fix it.

The only fault code is the O2 sensor. 2 different sensors have been installed & both still showed a fault code. They also checked the injectors for leakage. They changed the Motronic control unit & Ign. coil. Nothing helped. The way the bike runs its more than just dumping to much fuel. It barley has enough power to get going from a stop light.

I do have have a good Digital Multimeter but I'm not very good with electronics. The mechanical part of the engine (valve lash,compression test & leak down) is the same as it has been for the last 30,000 miles.

If there is any interest in the Charlotte NC area for a tech session I would be more than happy to have one. I have plenty of space & all the tools that would be needed.

Any thoughts: Thanks Dave
Hi Dave,

I have never heard of it happening on an LT, but your problem sure sounds like a clogged catalytic converter, especially given the O2 faults. Have you tried any troubleshooting in that direction? In fact I haven't personally seen a clogged cat for over 20 years, but who knows. You may have to try running with the O2 sensor removed to see if you have more power.

Also, I need to take my exhaust off very soon for welding. Would you want to try and swap it to yours?

John

2004 - LT - Anthracite
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post #31 of 131 Old Jul 27th, 2009, 2:07 pm
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Re: Electrical Help Needed

Since the wiring on the O2 sensors checks out we can conclude that the fault code is being caused by the O2 sensor readings being outside the allowed parameters written into the engine control module. This can only be caused (probably) by the inability of the system to control the amount of fuel being delivered into the cylinders. My bet is you have a defective (leaking or slaving) injector or two. Pull all your plugs and turn your ignition switch to the on position while looking into each cylinder with a penlight. You will need to do this process with each cylinder. The fuel pump will activate for a couple of seconds each time as it pressurizes the fuel rail. If you see or smell any fuel this indicates a leaking (stuck open) injector. It's rare but does happen and would be a good double-check of the dealers work. Also have you checked your EVAP charcoal filter for clogging? Simply try running the cycle with a loose gas cap to see if that's the problem. It sure sounds like an electrical issue though since it started out intermittent and went full time. A defective TPS (throttle position sensor) will cause the symptoms you describe as well. As I recall there's some type of micro-switch on it that does not show up in the fault codes when it fails but I'm not positive on that.


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Last edited by deanwoolsey; Jul 27th, 2009 at 5:29 pm.
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post #32 of 131 Old Jul 27th, 2009, 5:27 pm Thread Starter
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Re: Electrical Help Needed

Bosch is one of our sponsors for the race team I work for. I just E-mailed our rep. on checking the injectors in my area. I removed the Cat. Converter after I got back from Vermont because you could only see thru the center of it. Also the air track is clear.

Dave Selvig
2004 Black LT
2000 Canon Red LT



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post #33 of 131 Old Jul 28th, 2009, 8:01 am
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Exclamation Re: Electrical Help

Quote:
Originally Posted by deanwoolsey
. A defective TPS (throttle position sensor) will cause the symptoms you describe as well. As I recall there's some type of micro-switch on it that does not show up in the fault codes when it fails but I'm not positive on that.
Take a look at post # 13 I made 4 days ago.
There is a test in the motronic menue #6 for the potentiometer . When defective or out of range the falt lies in the throttle valve stub.
# 15 on the menue is for fuel injector signal.
Good Luck.

Pete Murray
IBA # 359 and
2014 RT
1973 R75/5
2002 LT 171 K Gone
2008 FJR 36 K Gone
Stroudsburg, PA
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post #34 of 131 Old Jul 28th, 2009, 9:15 am
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Re: Electrical Help Needed

After mulling it over for awhile I'm leaning towards the TPS. A defective TPS keeps the spark advance retarded when it fails, thus the poor mileage and plug fouling. The manual description of potentiometer is more accurate as it is a variable output signal. However I think there is a micro-switch on it that tells the computer when the throttle is completely closed. I would think either the potentiometer or the switch failing could be the problem. It's certainly worth a look since it sounds like you're already in there that far.


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post #35 of 131 Old Jul 28th, 2009, 5:26 pm Thread Starter
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Re: Electrical Help

Quote:
Originally Posted by murray
Take a look at post # 13 I made 4 days ago.
There is a test in the motronic menue #6 for the potentiometer . When defective or out of range the falt lies in the throttle valve stub.
# 15 on the menue is for fuel injector signal.
Good Luck.
The dealer said the only fault they had was the O2 sensor. With out the electrical value of the Throttle Position Potentiometer I don't have any way to check it.

Dave Selvig
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2000 Canon Red LT



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post #36 of 131 Old Jul 28th, 2009, 6:15 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by deanwoolsey
After mulling it over for awhile I'm leaning towards the TPS. A defective TPS keeps the spark advance retarded when it fails, thus the poor mileage and plug fouling. The manual description of potentiometer is more accurate as it is a variable output signal. However I think there is a micro-switch on it that tells the computer when the throttle is completely closed. I would think either the potentiometer or the switch failing could be the problem. It's certainly worth a look since it sounds like you're already in there that far.
It idles ok and I have suspected for some time that the timing is retarded it just feels that way when I ride it. As bad as it runs & as much fuel as it is using the exhaust smells like its to hot. Unfortunately BMW won't give the voltage information needed to check it.

For an example on my 250hp Fuel Injected Mercury Marine engine on my pontoon boat the throttle position sensor voltage at idle is .90-1.00 volts & at wide open is 3.55-4.05 volts. When mine went bad I was able to set it with out there Digital Diagnostic Equipment. It just took longer with a volt meter.

I have decided not to spend one more penny on my bike unless I'm 100% sure on what is wrong with it. More than likely I'll finish taking it apart and sell it piece by piece.

Dave Selvig
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2000 Canon Red LT



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post #37 of 131 Old Jul 28th, 2009, 6:55 pm
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Re: Electrical Help

Quote:
Originally Posted by saddle-man
The dealer said the only fault they had was the O2 sensor. With out the electrical value of the Throttle Position Potentiometer I don't have any way to check it.
Dave the moditech/ motronic computer can isolate the potentiometer for testing. Perhaps your shop did not test the potentiometer and only the O2 senser.

Pete Murray
IBA # 359 and
2014 RT
1973 R75/5
2002 LT 171 K Gone
2008 FJR 36 K Gone
Stroudsburg, PA
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post #38 of 131 Old Jul 28th, 2009, 8:29 pm Thread Starter
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Re: Electrical Help

Quote:
Originally Posted by murray
Dave the moditech/ motronic computer can isolate the potentiometer for testing. Perhaps your shop did not test the potentiometer and only the O2 senser.
After the bike was there for almost six weeks & me asking them over & over to check everything they can with there equipment it wouldn't surprize me one bit.

Dave Selvig
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post #39 of 131 Old Jul 28th, 2009, 9:06 pm
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Re: Electrical Help Needed

Fuel Injectors 2,3, and 4....

They met their demise when the fuel pressure regulator went out and nearly twice the fuel pressure was being applied. It started as intermittent because injector 4 failed first followed soon after by injector 3. Injector 2 is bad as well, but not a full failure like 3 and 4.

It's all in the exhaust temps.....


That's my story and I'm sticking to it. Someone on this forum should have a spare fuel injector laying around that you could use for testing.

On Labor Day weekend, you should sponsor a 3 day tech session where no one may leave until Monday after 5:00pm or your bike is working, which ever comes first.

-------------------------------------------------------------------------------------------------------------------
Chad Albrecht
2002 Chartreuse Yellow and Black BMW K1200LT Tickets
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post #40 of 131 Old Jul 29th, 2009, 2:55 am
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Re: Electrical Help

Quote:
Originally Posted by saddle-man
The dealer said the only fault they had was the O2 sensor. With out the electrical value of the Throttle Position Potentiometer I don't have any way to check it.
That's easy. The TPS works on a 5V signal. At closed throttle you should see at or near .5V DC, at WOT (wide open throttle) you should see near 5V DC. You should be loking at pins A&B (or B&C) on the connector with the key on, engine NOT running.

I see you are in NC...Not too far from here, 4 hours

Last edited by Morley; Jul 29th, 2009 at 3:02 am.
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post #41 of 131 Old Jul 29th, 2009, 5:27 am Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by cealbrecht
Fuel Injectors 2,3, and 4....

They met their demise when the fuel pressure regulator went out and nearly twice the fuel pressure was being applied. It started as intermittent because injector 4 failed first followed soon after by injector 3. Injector 2 is bad as well, but not a full failure like 3 and 4.

It's all in the exhaust temps.....


That's my story and I'm sticking to it. Someone on this forum should have a spare fuel injector laying around that you could use for testing.

On Labor Day weekend, you should sponsor a 3 day tech session where no one may leave until Monday after 5:00pm or your bike is working, which ever comes first.
I saw a max pressure of 80psi which is 22.7 psi above what my clymers calls for. I'm also not sure how much the exhaust temps vary at idle. The butterfly being just a hair off could change temps at an idle.

Dave Selvig
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post #42 of 131 Old Jul 29th, 2009, 5:36 am
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Re: Electrical Help Needed

Dave, I do have a spare set of injectors if you want to borrow. Just PM me your addy.

dan martin
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post #43 of 131 Old Jul 29th, 2009, 9:55 am
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Re: Electrical Help Needed

Yeah, I took another peek into my manual and it puts the spec at 49.80 psi when idling and it warns that the pressure should not be lower than this. It says nothing about the pressure going higher. But the purpose of a pressure regulator is to maintain a set maximum pressure. I think that the maximum should have always been 49.80 psi, so a reading of 80 sounds like it's 60% above the maximum at idle. From all of the posts, I think that the only thing to be confirmed as a failure is the pressure regulator.

I've worked as a Customer Support Engineer for 20 years repairing complex semi-conductor manufacturing equipment. At least once a year, there was always a system that would seem to go completely "hay-wire". Those systems almost always had secondary and tertiery failures related to the main-diagnosed failure. I just have the feeling that this is what has happened on your LT.

No one wants to see you part out the bike after all this hard work and money that you've put in. We should start a list of known goods and known bads and still suspect.

Known Good
O2 sensor
temp sensors
motronic computer
electrical connections
spark plugs
Cat. Converter
charcoal filter
air intake

Known Failures
fuel pressure regulator

Still Suspect
TPS sensor
Fuel Injectors

I'm sure I missed something. Please add to the lists, especially if it's a 'known good'. I've always found that the more things that you can rule out, the easier it is to find the real culprit.

-------------------------------------------------------------------------------------------------------------------
Chad Albrecht
2002 Chartreuse Yellow and Black BMW K1200LT Tickets

Last edited by cealbrecht; Jul 29th, 2009 at 9:59 am. Reason: added a few items
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post #44 of 131 Old Jul 29th, 2009, 7:54 pm Thread Starter
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Re: Electrical Help

Quote:
Originally Posted by Morley
That's easy. The TPS works on a 5V signal. At closed throttle you should see at or near .5V DC, at WOT (wide open throttle) you should see near 5V DC. You should be loking at pins A&B (or B&C) on the connector with the key on, engine NOT running.

I see you are in NC...Not too far from here, 4 hours
I just checked the voltage on the TPS at the pins for the Motronic Control Unit pin#3 0 volts pn#5 0 to .4 & fluctuating with throttle open or closed pin#9 0 volts pin#22 0 volts.

Dave Selvig
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2000 Canon Red LT



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post #45 of 131 Old Jul 29th, 2009, 8:12 pm
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Re: Electrical Help Needed

Measure pin 22 to ground (brown wire or batt-) that should have the 5 V on it (listed signal is -G) also the temp sensor and air temp sensor tie here as well. If not 5V there then it would be pin 3 to ground (signal is DKP+). The pots are measured from pin 5 and pin 9 at the motronic and these would be measured to ground respectively.

John
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post #46 of 131 Old Jul 29th, 2009, 8:14 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by DanMartin
Dave, I do have a spare set of injectors if you want to borrow. Just PM me your addy.

dan martin
Thanks Dan I'll keep your offer in mind. Is there are any # on the injectors that you can see. I haven't pulled mine out yet. For now I'm trying to keep it easy to run it as I check things. I also checked the hall effect sensor to see if a crankshaft seal had failed & filled it with oil. It was completely dry no oil or water moisture. I'll have to install the right radiator & fill it before I start it next.

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2000 Canon Red LT



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post #47 of 131 Old Jul 29th, 2009, 8:20 pm Thread Starter
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Re: Electrical Help Needed

Quote:
Originally Posted by jzeiler
Measure pin 22 to ground (brown wire or batt-) that should have the 5 V on it (listed signal is -G) also the temp sensor and air temp sensor tie here as well. If not 5V there then it would be pin 3 to ground (signal is DKP+). The pots are measured from pin 5 and pin 9 at the motronic and these would be measured to ground respectively.
Thanks John but this is where my lack of electorial know how hurts me. I can't follow what you are telling me.

Dave Selvig
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2000 Canon Red LT



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post #48 of 131 Old Jul 30th, 2009, 12:24 am
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
Thanks Dan I'll keep your offer in mind. Is there are any # on the injectors that you can see. I haven't pulled mine out yet. For now I'm trying to keep it easy to run it as I check things. I also checked the hall effect sensor to see if a crankshaft seal had failed & filled it with oil. It was completely dry no oil or water moisture. I'll have to install the right radiator & fill it before I start it next.
part # 0280150705 on each injector

dan
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post #49 of 131 Old Jul 30th, 2009, 2:31 am
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Re: Electrical Help Needed

Quote:
Originally Posted by saddle-man
I saw a max pressure of 80psi which is 22.7 psi above what my clymers calls for. I'm also not sure how much the exhaust temps vary at idle. The butterfly being just a hair off could change temps at an idle.
There's the culprit. With fuel pressure that high you are over fueling the engine and even with the feedback from the O2 sensor the motronic can't shorten the injector pulse width enough. Time to look at the regulator.
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post #50 of 131 Old Jul 30th, 2009, 2:34 am
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Re: Electrical Help Needed

If anyone knows the lbs/hr rating for the LT's injectors he can get them much cheaper from Five-O motorsports.
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