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Discussion Starter #1
My bike hesitates during acceleration. I have replaced the fuel filter(NAPA Gold), fuel lines and fuel lines in the tank with submersible rated lines. I have also replaced the spark plugs, spark plug wires and check the valves. I struggle to accelerate to 100mph (i know that is fast but I wanted to see does the hesitation goes away). I made my own copper breathing tube and replaced the vacuum lines on the throttle body. Since I removed the fuel rail with the injectors, could I be having injector issues as well? Should I also replace the fuel pump and fuel injectors? I have a 153K on the bike and the fuel pump is probably the original one. I saw these injectors on ebay. Has anyone used these 4PCS New 14lb Fuel injectors for BMW K1100RS K1100LT K1200LT K1200GT K1200RS Initially the bike idles up and down and then settles down and idles normally. By the way, I disconnected the battery so that the ECU would reset itself. It appears as though the bike is have a fuel/air issue. Any help is truly appreciated.
 

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You probably thought of this but the fuel filter flow is one way.
 

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If you used NGK plugs double check that your not getting misfire. The NGK plugs are slightly shorter than Bosch plugs and will arc down the side to the block. Pull the cover and start the bike in a dark garage. You may also have a leak around the intake, try one of the many leak check ideas and see what you find.
 

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My bike hesitates during acceleration. I have replaced the fuel filter(NAPA Gold), fuel lines and fuel lines in the tank with submersible rated lines. I have also replaced the spark plugs, spark plug wires and check the valves. I struggle to accelerate to 100mph (i know that is fast but I wanted to see does the hesitation goes away). I made my own copper breathing tube and replaced the vacuum lines on the throttle body. Since I removed the fuel rail with the injectors, could I be having injector issues as well? Should I also replace the fuel pump and fuel injectors? I have a 153K on the bike and the fuel pump is probably the original one. I saw these injectors on ebay. Has anyone used these 4PCS New 14lb Fuel injectors for BMW K1100RS K1100LT K1200LT K1200GT K1200RS Initially the bike idles up and down and then settles down and idles normally. By the way, I disconnected the battery so that the ECU would reset itself. It appears as though the bike is have a fuel/air issue. Any help is truly appreciated.
I believe you have a 99 from previous posts. Can you describe the hesitation a little better? Is it a stumble that continues to happen or is it a loss of power on the way up? The early LT's had an issue with poor performance when it got over 80 degrees. Look under your seat and see if there is a small brown wire loop on the right side wiring harness ( I believe) Check to see if it is cut or not and also check to make sure the air box temp sensor front left is connected. As sailor always says, it is difficult to diagnose these things from a distance.

Without a GS911 to pull some engine data from the sensors, the first thing is to simply validate a few things and go from there.
 

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Discussion Starter #5
I have NGK plugs and I am getting arcing mainly in cylinder four and maybe cylinder 3. I have just installed some NGK wires from Euromoto electrics https://www.euromotoelectrics.com/Ignition-Wire-Set-K1200-BMW-WSK1200-p/bmw-wsk1200.htm 2 days ago. I check the plugs and they are installed correctly and are not loose. Should I switch to the plugs that the bike comes with and go back to my original wires. I changed the wires as a preventative measure. Your thoughts and thanks for telling me to look in the dark for arcing. I am assume that this problems makes my bike hesitate. What I mean by hesitation is that it jerks as it is accelerating and it seems as though the bike wants to run full throttle but it runs as though something is stopping it from running to it's full potential. The arcing I am assuming makes it misfire.
 

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I have NGK plugs and I am getting arcing mainly in cylinder four and maybe cylinder 3. I have just installed some NGK wires from Euromoto electrics https://www.euromotoelectrics.com/Ignition-Wire-Set-K1200-BMW-WSK1200-p/bmw-wsk1200.htm 2 days ago. I check the plugs and they are installed correctly and are not loose. Should I switch to the plugs that the bike comes with and go back to my original wires. I changed the wires as a preventative measure. Your thoughts and thanks for telling me to look in the dark for arcing. I am assume that this problems makes my bike hesitate. What I mean by hesitation is that it jerks as it is accelerating and it seems as though the bike wants to run full throttle but it runs as though something is stopping it from running to it's full potential. The arcing I am assuming makes it misfire.
Yes, arcing is almost certainly causing your bike to misfire. I would try first putting the factory spec plugs back in. If you still have arcing, then I would look at the wires. Do things one step at a time or you won't know where the problem was.
 

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I have NGK plugs and I am getting arcing mainly in cylinder four and maybe cylinder 3. I have just installed some NGK wires from Euromoto electrics https://www.euromotoelectrics.com/Ignition-Wire-Set-K1200-BMW-WSK1200-p/bmw-wsk1200.htm 2 days ago. I check the plugs and they are installed correctly and are not loose. Should I switch to the plugs that the bike comes with and go back to my original wires. I changed the wires as a preventative measure. Your thoughts and thanks for telling me to look in the dark for arcing. I am assume that this problems makes my bike hesitate. What I mean by hesitation is that it jerks as it is accelerating and it seems as though the bike wants to run full throttle but it runs as though something is stopping it from running to it's full potential. The arcing I am assuming makes it misfire.
I don't think the new wires are the issue exactly. What I found is the NGK plugs were slightly shorter on the insulation/contact side keeping them from making contact in the plug wire boot. This made the electricity jump across the gap and part of it ran down the outside to the closest ground. Once I put the slightly longer Bosch plugs back in the arcing stopped. You can measure the distance from the end of the boot to the contact pad inside then compare that to the length of the spark plug from the tip to the bottom of the insulator and see if the plug is to short. There are several who have used NGK plugs so they must work with some plug wires.
 

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I don't think the new wires are the issue exactly. What I found is the NGK plugs were slightly shorter on the insulation/contact side keeping them from making contact in the plug wire boot. This made the electricity jump across the gap and part of it ran down the outside to the closest ground. Once I put the slightly longer Bosch plugs back in the arcing stopped. You can measure the distance from the end of the boot to the contact pad inside then compare that to the length of the spark plug from the tip to the bottom of the insulator and see if the plug is to short. There are several who have used NGK plugs so they must work with some plug wires.
I am using the NGK Iridium plugs and also the NGK wire set from EME and have no issues at all on my 01. If you are actually seeing arcing around the plug wires, then you do have a problem with something in that area. Either the plug wires re not seated properly or as mentioned, there is some incompatibility. What NGK plugs are you running?
 

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Discussion Starter #9
I am running NGK 3144 DCPR7EIX IRIDIUM IX Spark Plugs. I put the original wire in last night as well and I sawing arcing on cylinder 4 as well. I ordered the original XR7LDC plugs today and I should have them on Wednesday.
 

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I am running NGK 3144 DCPR7EIX IRIDIUM IX Spark Plugs. I put the original wire in last night as well and I sawing arcing on cylinder 4 as well. I ordered the original XR7LDC plugs today and I should have them on Wednesday.
Double check that one #4 plug when you remove it and make sure the gap isn't oddly large in comparison. The plugs come properly gaped but if it was damaged in some way or had an oddly large gap, it may have an easier time jumping outside but I have no such issue with the same setup.

Good luck with the Bosch plugs. Going to state the obvious for those who don't know. Those plugs also come pre-gaped so no adjustment should be necessary but to check them requires a wire feeler gauge because the electrode is on the side of the anode and has a curved surface rather than flat so a standard gauge will give an incorrect reading.
 

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its not hard to crack the porcelain on the plug when installing plugs if you are not straight on with the tool using an extra long extension, you tend to push down on the ratchet while tightening.
 
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I am using the NGK Iridium plugs and also the NGK wire set from EME and have no issues at all on my 01. If you are actually seeing arcing around the plug wires, then you do have a problem with something in that area. Either the plug wires re not seated properly or as mentioned, there is some incompatibility. What NGK plugs are you running?
I had DCPR7E in it. They are supposed to be an alternative and may be fine with different plug wires. I believe I had stock wires and the boot just seems to long. They were pushed on as far as they could go so the only thing I can think is the plug is to short. Odd considering the JIS standard is longer then the ISO standard. I can't find a spec for the length of the Bosch plug to compare and didn't think to measure the boot when I had it apart.
 

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I am running NGK 3144 DCPR7EIX IRIDIUM IX Spark Plugs. I put the original wire in last night as well and I sawing arcing on cylinder 4 as well. I ordered the original XR7LDC plugs today and I should have them on Wednesday.
It sounds like the plug. As mentioned, double check the gap and insulator. It's easy for them to crack and be hard to see if it's around the base.
 

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I had DCPR7E in it. They are supposed to be an alternative and may be fine with different plug wires. I believe I had stock wires and the boot just seems to long. They were pushed on as far as they could go so the only thing I can think is the plug is to short. Odd considering the JIS standard is longer then the ISO standard. I can't find a spec for the length of the Bosch plug to compare and didn't think to measure the boot when I had it apart.
I don't have a spare NGK DCPR7XIE to measure but I do have the Bosch XR7LDC I removed so here is a measurement of it for someone to compare with.
 

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I don't have a spare NGK DCPR7XIE to measure but I do have the Bosch XR7LDC I removed so here is a measurement of it for someone to compare with.
I measured one of the DCPR7E I have and it was 2.08 inches from base to contact tip which matches the JIS length. Next time I pull my plug I'll measure the boot to see what it measures.

The Bosch plug looks like it's around 2.18 inches give or take. Not much of a difference but could be enough if the contact in my boot is worn or pushed back. Something else for me to check when I have another maintenance day.
 

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Discussion Starter #17
I replaced the plugs with the XRLDC plugs and the arcing is gone. I am still having a small amount of hesitation but nothing like it was doing with the NGK plugs. The main issue is that in 5th gear the power isn't there like in 4th gear. I do not get the acceleration and something isn't quite right. I have disconnected the battery to reset the monotronic unit. I wonder am I having a TPS problem since 5th gear is the problem. My cat plug in the rear was gone when I purchased the bike and the air box temp sensor is connected since based on the forum, you don't want both disconnected. I replaced the O2 sensor(NEW BOSCH 15738 UNIVERSAL Oxygen Sensor 4 WIRES) and the fuel filter(NAPA Gold one) and the arrow is pointing in the correct position. Any additional help would be appreciated and thanks for all of your help so far.
 

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Well, it is only 98 HP at 7K. I don't spend time trying to get my bike to go fast. 5th gear is pretty high and the top rated speed is only 123mph but you will never see that unless down hill with a strong tail wind. There are ways to do some tests on the TPS but it is more likely to be a flat spot as you turn the throttle rather than hesitation while holding it at full. You need an analog meter or do the test or the GS911 to see if there is any dead spots in the TPS range. You may still be getting some arcing under load if it is still a stutter you are equating to hesitation. Did you inspect the boots on the plug wires well for any cracks or damage while you replaced the plugs this time?


You could have dirty injectors, low fuel pressure or the hesitation issue from 80+ degrees. Someone else will have to tell you if the 99 had a cat code plug or not as Kirk has already mentioned having to unplug the air box temp sensor on a 99 with no brown wire for that particular issue so it may never have had one. Again, difficult to diagnose this type of issue remotely. It should not stutter ( miss) so if it is still doing that, we need to figure out the reason for that. Plugs made it better. If your original wires are/were good when you removed them, you might go back to them and test with them so see if you can eliminate the miss if that is what it is. If it isn't a miss, describe it better for us to muse on it.
 

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What ^^^ he said.
5th gear is really an overdrive gear that doesn't have much torque. Also determine if it's a hesitation before you get the expected power or if it's just a lack of power. The rpm and speed makes a big difference. I never shift to 5th until I'm going 70 for a lengthy time or hit 80. Even at 80 it's not snappy like it is in the lower gears.
 

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Discussion Starter #20
Let me say thank you for your help everyone. The problem is solved and I am truly embarrassed to tell you what I did. When I removed the throttle body and reconnected it due to me making a copper breather hose, I connected the fuel injector lines incorrectly. I connected the pulse valve up to one of the connectors as well. If it wasn't for a similar post, I never would have looked at the connectors. The pulse valve connector and the injector connectors are identical. I will be changing the oil again since the oil was probably contaminated and I will be adding a 20W50 Castrol synthetic blend. Once I button her back up, I will be riding again. The weather is pretty bad so my 6100 mile trip is going to be delayed. Thanks again everyone.
 
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