Fuel Injection Maintenance - Cleaning, Adjustment, Balance.

[gmcjetpilot]

So Fritz is back on the road after 5 years thanks to HELP from BMW Sport Touring Community. Thanks again. IT IS RUNNING AMAZING.   However I did nothing with the FUEL Injectors. Besides the tank pump, filter, hose rebuild I did nothing with checking, cleaning, adjusting the FUEL INJECTION....

 

I read people cleaning something, may be LEFT RIGHT Sync?  I have Clymer manual. Right now I think it is running perfect. So the old adage "If it ain't broke don't fix it".    After I fixed the tank fuel supply the bike started right up and idled nicely. The on road performance is very nice.... no hesitation, smooth, tons of power. 

 

I might not tackle this tomorrow, but would like to plan going through the fuel injection system. What tasks are advised? What new parts / seals, what tools do I need? I assume I need a Fuel Injection Syntonizer of some kind. May be do nothing? It is running well.

 

I use to balance carbs on a 4 cyl bike with 4 vacuum monometers. Never synced Fuel Injection. Trouble shooting the dead fuel pump dirtrider mentioned remapping the throttle.. I never did that re-map when I realized the in tank pump was dead ( no pump cycle on initial power up, power to fuel injector,  blowing pump fuse, no start). So I did not remap the FI.  All my cars with FI just worked. No need to mess with them. All my past bikes were carbs. 

 

BONUS Question: What kind of highway mileage should I get? I looked up my old Fuelly Tracker and had about 43.4 mpg  Avg. Is that what others get. Right now my working capacitance fuel sender gauge is not working or intermittent. I do believe the low fuel light is working. I may have to time the tank for refueling.   I figure 200 mile full tank range is safe. I know I don't want to suck it down low.... the fuel pump needs fuel to keep it cool. 

 

[dirtrider]

21 minutes ago, gmcjetpilot said:

So Fritz is back on the road after 5 years thanks to HELP from BMW Sport Touring Community. Thanks again. IT IS RUNNING AMAZING.   However I did nothing with the FUEL Injectors. Besides the tank pump, filter, hose rebuild I did nothing with checking, cleaning, adjusting the FUEL INJECTION....

 

I read people cleaning something, may be LEFT RIGHT Sync?  I have Clymer manual. Right now I think it is running perfect. So the old adage "If it ain't broke don't fix it".    After I fixed the tank fuel supply the bike started right up and idled nicely. The on road performance is very nice.... no hesitation, smooth, tons of power. 

 

I might not tackle this tomorrow, but would like to plan going through the injection system, what tasks are advised, new parts / seals, what tools do I need? I assume I need a Fuel Injection Syntonizer.  I use to balance carbs on a 4 cyl bike with mercury vacuum monometer. Never synced Fuel Injection. Trouble shooting the dead fuel pump dirtrider mentioned remapping the throttle.. All my cars with FI just worked. No need to mess with them. 

 

PS BONUS Question: What kind of highway mileage. I looked up my old Fuelly Tracker and had about 45 mpg. Is that what others get. Right now my working capacitance fuel sender gauge is not working or intermittent. I do believe the low fuel light is working. I may have to time the tank for refueling.   I figure 200 mile full tank range is safe. I know I don't want to suck it down low.... the fuel pump needs fuel to keep it cool. 

Evening   gmcjetpilot

 

Depending on your riding style & speed 45mpg isn't bad. Probably go up slightly at a sustained 55--60 mph & down a fair amount at a sustained 85 mph. 

 

On the fuel gauge not working correctly,  there is a float inside a tube in the fuel tank, that float rides up & down on two thin resistor wires. That change in resistance is what causes the fuel level reading to change. You don't have a  capacitance fuel sender you have a resistive fuel sender. 

 

That float on the back of the fuel pump plate is ONLY for the low fuel light. (that is a switch not a resistor) 

 

Does you fuel gauge level vary with  the engine running or not running? If it changes with the engine running then look for a resistance issue in the brown wire going to the pump plate & pump. 

 

If it runs good now then I wouldn't do a throttle balance yet. Wait until next valve check, or when you have the plastics off next. You really should check/set the valves before doing a TB balance 

 

You might try putting a little Techron concentrate in each fuel fill up for a few tank fulls, that will clean you injectors but it might also help your fuel gauge as those resistor wires inside that float tube can get some varnish on them preventing the float contacts from making good continuous contact.   

[Skywagon]

gmcjetpilot… when I had my 1150 RT I could count on 43-44mpg at 65 and less. At 85 as DR noted I would get 38-39. 

[gmcjetpilot]

Got it. The float is resistance not capacitance. I had it working b4 the pump failure. Actually repaced it with a new used part last time I had tank off. Thought it was still working but it's blank or showing 3 or 4 bars; which may be correct. I have not topped tank up yet. I'll tolerate the fuel level gauge issue. I road for decades w/ no fuel gauge on other bikes (but they had reserve fuel select on tank petcock).

 

I'm still using ethanol free regular. Eventually I'll have to fill it with E10 premium on road trips. E free fuel is not easy to find.  I hate ethanol. It did a number on my emergency gasoline generator for home. I also blame ethanol for the hose rot inside the R1150RT's fuel tank. I know it calls for premium fuel, but if conservative, avoiding hard acceleration there should be no worries with detonation. 

 

Good to know milage per gallon. Great tip on speeds. I'll have to calculate fuel stops or relyi on low fuel float switch which I'm sure is working. 

 

I'll tackle fuel injection inspection/ clean/ adjust next time I service bike. I'll be sure to do valve adjustment first. I'll see if I can borrow a synchronizing tool. It's running so well now, with new spark plugs, valves adjusted, fresh oil/filter, it's best to leave it be and go ride.

[dirtrider]

7 hours ago, gmcjetpilot said:

Got it. The float is resistance not capacitance. I had it working b4 the pump failure. Actually repaced it with a new used part last time I had tank off. Thought it was still working but it's blank or showing 3 or 4 bars; which may be correct. I have not topped tank up yet. I'll tolerate the fuel level gauge issue. I road for decades w/ no fuel gauge on other bikes (but they had reserve fuel select on tank petcock).

 

I'm still using ethanol free regular. Eventually I'll have to fill it with E10 premium on road trips. E free fuel is not easy to find.  I hate ethanol. It did a number on my emergency gasoline generator for home. I also blame ethanol for the hose rot inside the R1150RT's fuel tank. I know it calls for premium fuel, but if conservative, avoiding hard acceleration there should be no worries with detonation. 

 

Good to know milage per gallon. Great tip on speeds. I'll have to calculate fuel stops or relyi on low fuel float switch which I'm sure is working. 

 

I'll tackle fuel injection inspection/ clean/ adjust next time I service bike. I'll be sure to do valve adjustment first. I'll see if I can borrow a synchronizing tool. It's running so well now, with new spark plugs, valves adjusted, fresh oil/filter, it's best to leave it be and go ride.

Morning gmcjetpilot

 

What you replaced was the low fuel light float as THAT is what is attached to the fuel pump plate. 

 

The actual fuel gauge float is a long tube that is attached thorough a hole in the top of the fuel tank (that tube has a sliding float inside it that slides up & down on thin wires as the fuel level changes). The wire pigtail from that tube plugs into the back side of the fuel pump pass through plate. (you did plug that in when you reinstalled the pump assembly didn't you?)

 

One of the problems with the BMW 1100/1150 fuel gauge is that it shares a low (ground) with the fuel pump (brown wire)  so any resistance in that brown wire, it's chassis connection, or with it's ground path all the way back to the battery (-) post can effect fuel gauge accuracy.

 

In some cases on the old BMW  1100/1150, to achieve fuel gauge accuracy, it is necessary to run a separate ground wire from the fuel pump pass-through plate, and/or the brown wire at the pump pigtail connection, all the way back to the battery's negative post. 

 

You don't need to borrow a synchronizing tool as the best tool for "Throttle Body" balancing on the BMW boxer is a simple homemade liquid "U" tube manometer. A "U" tube manometer won't work on most engines that don't have opposing vacuum pulses but on the 2 cylinder BMW 1100/1150 boxer with  360° firing pulses they can't be beat for accuracy.  

 

[man1nvan]

Nice tidy bike.  if it is running well leave it alone and ride it.  i love the way these are simple to work on BUT getting everything in balance is a finnicky job and once they are running right they stay that way  for a long time.  my throttle bodies have started rattling a bit but i am still getting 45mpg and i have no surging or flat spots so it will stay as it is until something changes.  when i do mine i check everything TPS, rocker end float, valves, injectors, plugs... balance it up then i ride it until something goes wrong!  DR is right  a bit of plastic tube with some oil in it works a treat for balancing  another handy tip from this forum.

[jacksdad63]

In the above fuel figures, I assume you are talking about the crazy mercan gallons which aren't real full Imperial gallons? 

[gmcjetpilot]

On 5/16/2023 at 5:23 AM, dirtrider said:

Morning gmcjetpilot

 

What you replaced was the low fuel light float as THAT is what is attached to the fuel pump plate.....

 

Yes Mr. Dirtrider, I replaced the vertical tube, fuel level (LCD gauge) last time I had tank off 5 yrs ago, to repair the leaking O-Ring on the tank plate.  Never replaced low fuel level float Assy.  My fuel level was dead 5 years ago, no indication of any kind.   So I replaced the large vertical float tube fuel sender. with a used  one. After back together everything, including fuel level was working.  Flash forward 

 

This time with tank off fixing the fuel pump, after getting tank back on,  I added fuel, noted LOW level fuel light extinguished and fuel LEVEL started to indicate, up tp 3 LCD segments, which seemed reasonable for the amount of fuel added. It start acting up on after a few rides. It went away. Came back... then gone. 

 

Quote

The actual fuel gauge float is a long tube that is attached thorough a hole in the top of the fuel tank (that tube has a sliding float inside it that slides up & down on thin wires as the fuel level changes). The wire pigtail from that tube plugs into the back side of the fuel pump pass through plate. (you did plug that in when you reinstalled the pump assembly didn't you?)

 

YEP, that is what I replaced 5 yrs ago. Yes when I put it back together I installed the fuel level plug back into the connector on the plate, as well as the two vent lines.  FUN!  I could not get the plate back on because the vent hose camps no matter how I clocked them were causing a small interference. I went with spring clamps.  Not factory but seems to work fine, There is no real pressure in the hose.

 

Quote

One of the problems with the BMW 1100/1150 fuel gauge is that it shares a low (ground) with the fuel pump (brown wire)  so any resistance in that brown wire, it's chassis connection, or with it's ground path all the way back to the battery (-) post can effect fuel gauge accuracy.

 

In some cases on the old BMW  1100/1150, to achieve fuel gauge accuracy, it is necessary to run a separate ground wire from the fuel pump pass-through plate, and/or the brown wire at the pump pigtail connection, all the way back to the battery's negative post. 

 

Got it. Thanks for the TIP... I am hoping for SELF REPAIR... In that full it with fuel and start riding it. I will have to note millage at fill up. I also want to verify the low level fuel light is working. From the SPECS the bike has a 250 mike max range.  I will get fuel at 200 miles. The tank is suppose to carry 6.6 gal I need to stop for a break way before that. 

 

Quote

You don't need to borrow a synchronizing tool as the best tool for "Throttle Body" balancing on the BMW boxer is a simple homemade liquid "U" tube manometer. A "U" tube manometer won't work on most engines that don't have opposing vacuum pulses but on the 2 cylinder BMW 1100/1150 boxer with  360° firing pulses they can't be beat for accuracy.  

 

THING OF BEAUTY... I love making tools.... that is what I will do. 'Fritz' is running ridiculously smooth for twin boxer.  I will plan the FUEL balance and fuel level trouble shoot after I put a few 1000 miles on it.

THANKS A MILLION FOR THE HELP.... 

[jacksdad63]

My 1100RT low fuel light came on after I removed/refitted the fuel tank, it was the wiring block connector. Its been unplugged many times over 25 years! 

I just gave the block connector a spray with electrical cleaner and then a WD40 type oil, and pushed both parts firmly together, the light went out...I will have to run it lowon fuel now to see when it comes back on for real. 

[dirtrider]

14 hours ago, jacksdad63 said:

My 1100RT low fuel light came on after I removed/refitted the fuel tank, it was the wiring block connector. Its been unplugged many times over 25 years! 

I just gave the block connector a spray with electrical cleaner and then a WD40 type oil, and pushed both parts firmly together, the light went out...I will have to run it lowon fuel now to see when it comes back on for real. 

Morning  jacksdad63

 

Something not making sense with that, the low fuel sender is basically just a make-contact switch, it is either open (no low fuel light on) or closed (low fuel light on).

 

If there is a high resistance problem, or a poor contact problem in the circuit then you have (no-low-fuel-light-on) no matter how low the fuel gets.  A high resistance issue, or poor connector terminal contact prevents the low fuel light from coming on, it doesn't make the low fuel light come on. 

 

The usual causes of the low light staying on are: the float disintegrating then falling off the float arm (that allows the float arm to eventually drop to the bottom of travel closing the low-fuel switch, or the float, or float arm, is contacting something inside the tank, like a wire, hose or hose clamp preventing the float from rising up with the fuel level.   

 

Or, on an incorrectly reading low fuel light (still works OK just not at the correct point of fuel level) is a bent float arm usually caused by removing or installing the pump plate assembly with the float arm catching on something during that procedure. Or a partially disintegrated, or fuel-logged, float causing it to not float to the correct fuel level. 

[gmcjetpilot]

WELL WELL. My Bike fixes it self. I guess I was low on fuel. I never filled up. I had about 2 gal in it, may be a bit more. I put in a little at a time from fuel jugs (using up my ethanol free fuel I had). Finally filled up. LCD fuel level came back. Full it looks like it's a bar  segment not showing. Good enough. I set the trip and will monitor.

[Michaelr11]

2 hours ago, gmcjetpilot said:

Finally filled up. LCD fuel level came back. Full it looks like it's a bar  segment not showing.

 

Clean the under-tank electrical connector on the right side with electrical contact cleaner.  Spray it several times, separate the the two parts, spray each several times. That should clear up the missing bar on the fuel level gauge.

 

[gmcjetpilot]

16 hours ago, Michaelr11 said:

 

Clean the under-tank electrical connector on the right side with electrical contact cleaner.  Spray it several times, separate the the two parts, spray each several times. That should clear up the missing bar on the fuel level gauge.

 

Great tip. I have D5 deoxit.

[gmcjetpilot]

UPDATE.... After a 2500 miles, 12 days, 5 states, ride including the RA Rally in Davis WV, 480 miles of Blue ridge, SC, Tail Of Dragon (deals gap US129) N and S, Cherohala Skyway and many fill ups (some half tank) the fuel level became MORE reliable.

 

Not 100% but much better. Towards the end of the trip it was consistently working except went blank once. Then came back after a refill and continued to work until I got home. The fuel level reading range increased from only one bar short at full. Low went down to 1 bar. Note I never let fuel get too low to point of low fuel light, as fuel availability on the Blue Ridge and back roads in SC, NC, TN was uncertain.  Before the trip if it worked it was at least 2 bars low at full and almost always went blank at or below 3 bars. So except for full being one segment short it is reading full scale. 

 

I did have Tupperware off Before the trip to replace the Halogen lights with LED's (see other thread). I cleaned the tank connection with "DeoxIT D5". I work on for hobby electronics, amps, ham radios, vintage tube radios. Deoxit is great for POTS and connections. I rolled emery cloth to clean both sides of connector socket and pin side. Not aggressive just a scuff, with the D5.  You can get D5 at music stores, online. Don't use WD40 if you can help it. Yes it will work but D5 is made for cleaning electrical connections.  Bottom line the connector cleaning did not do anything for at least 5 days of the 12 day ride. I suspect it is the float tube sender in the tank has issues. I suppose as dirtrider said it may clean it self. Clearly lots of fill ups and vigorous riding got it better. But it is not 100%. I would say 80% reliable and 90% accurate when working.

 

I always reset OD at fill up. I know unloaded, solo, riding "normal" I can get 270 miles before low level fuel light normally. On the trip my "BINGO" miles was 240 miles just for extra reserves and lower fuel economy with the weight and riding I was doing. I estimate low fuel light  means another 30 miles? Never tested it but based on fill ups I can add about 5.9 gal, a little more if riding on low fuel light for say 10 or more miles. Capacity spec of 6.6 gal I recall that means I had 0.5 to 0.7 Gal remaining. My MPG is about 43-46 mpg. Full cargo (camping, food for 6 days of primitive camping, ice chest, clothes ) closer to 42 mpg. 

[dirtrider]

3 minutes ago, gmcjetpilot said:

UPDATE.... After a 2500 miles, 12 days, 5 states, ride including the RA Rally in Davis WV, 480 miles of Blue ridge, SC, Tail Of Dragon (deals gap US129) N and S, Cherohala Skyway and many fill ups (some half tank) the fuel level became MORE reliable.

 

Not 100% but much better. Towards the end of the trip it went blank once. Then came back after a refill. The range increased from only one bar short at full. Low went down to 1 bar. Note I never let fuel get too low to point of low fuel light, as fuel availability on the Blue Ridge and back roads in SC, NC, TN was uncertain. 

 

I did have Tupperware off Before the trip to replace the Halogen lights with LED's (see other thread). I cleaned the tank connection with "DeoxIT D5". I work on for hobby electronics, amps, ham radios, vintage tube radios. Deoxit is great for POTS and connections. I rolled emery cloth to clean both sides of connector socket and pin side. Not aggressive just a scuff, with the D5.  You can get D5 at music stores, online. Don't use WD40 if you can help it. Yes it will work but D5 is made for cleaning electrical connections.  Bottom line the connector cleaning did not do anything for at least 5 days of the 12 day ride. I suspect it is the float tube sender in the tank has issues. I suppose as dirtrider said it may clean it self. Clearly lots of fill ups and vigorous riding got it better. But it is not 100%. I would say 80% reliable and 90% accurate when working.

 

I always reset OD at fill up. I know unloaded, solo, riding "normal" I can get 270 miles before low level fuel light normally. On the trip my "BINGO" miles was 240 miles just for extra reserves and lower fuel economy with the weight and riding I was doing. I estimate low fuel light  means another 30 miles? Never tested it but based on fill ups I can add about 5.9 gal, a little more if riding on low fuel light for say 10 or more miles. Capacity spec of 6.6 gal I recall that means I had 0.5 to 0.7 Gal remaining. My MPG is about 43-46 mpg. Full cargo (camping, food for 6 days of primitive camping, ice chest, clothes ) closer to 42 mpg. 

Afternoon gmcjetpilot

 

Good to hear that it is running good.

 

You might try putting a little Techron in every other fill up. If you have some varnish on the fuel level sender tube resistor wires that can help to clean them. 

 

The other area to look at is the continuity between the low (brown wires) at the fuel pump pass through back to the battery negative post. Resistance in the low (ground) side of the fuel pump circuit is a known issue on the BMW 1100/1150 bikes. 

 

Some end up running an additional wire directly from the battery negative post to the brown wire connection at the fuel pump pass-through & also to the fuel pump pass through metal plate. 

 

 

[gmcjetpilot]

6 hours ago, dirtrider said:

Afternoon gmcjetpilot

 

Good to hear that it is running good.

 

You might try putting a little Techron in every other fill up. If you have some varnish on the fuel level sender tube resistor wires that can help to clean them. 

 

The other area to look at is the continuity between the low (brown wires) at the fuel pump pass through back to the battery negative post. Resistance in the low (ground) side of the fuel pump circuit is a known issue on the BMW 1100/1150 bikes. 

 

Some end up running an additional wire directly from the battery negative post to the brown wire connection at the fuel pump pass-through & also to the fuel pump pass through metal plate. 

 

Thanks Mr. Dirtrider. Fritz ran like a Champ overall not a hiccup on the almost two week trip.... from twistiness to highspeed. One question, you mean this stuff

 

 Techron .

 

I assume it is safe for rubber and all the stuff needless to say, since you would not suggest it. Cool. NAPA has best price. I'll order it now and pick it up tomorrow. I remember as a very young kid all the fas stations strived to get customers with their Techron or other additives. Also they had toys for kids, some of them pretty good, like tin metal models. I remember having something like a tow truck with name of gas brand... I wish I had it now. Might be worth some money.

 

As far as ground I remember you saying that. I check continuity but hear you. I think the issue is with the vertical tube sender internals.  I did rewire almost everything except the pig tail from the sender to the connector in the tank plate pass through. How about GROUND the sender which is exposed on top of tank?  I could easily run a wire under the fairing to ground. Brilliant idea or dumb?  First I need to determine if the metal sender housing is to ground. If adding ground helps great. I think it is the sender internal. This means fairing has to come off which is in works as I have to swap out cheap LED Fog lights for good ones. It is easier than removing the tank.

 

Taking the tank off or worse pulling the fuel pump, filter, low fuel float assembly out is a non starter.  I still have PTSD from the last go at it. Successful but I like to ride it more and work on it less. Ha ha.

 

So Techron it is. Fingers crossed. However as of now it is petty good. It is not a huge deal, I rode bikes for a long time with NO fuel level of any kind. It is just I hate things not working. If it's there I want it to work.  I can say it is pretty accurate in that it marched down in a linear fashion with miles.                        

 

QUESTION.... How does the fuel get from LEFT and RIGHT side of tank to the pickup. May be it is an optical illusion. I recall the pickup is on right side of tank inner wall. RT tank is asymmetric as left side has pocket for the glove box (radio box option) in the fairing to fit into. I suppose the back of tank is lower and left side can drain to right especially accelerating. I remember older bikes I had +40 yrs ago had a balance tube across the bottom of tank. I don't see those anymore. 

 

BONUS QUESTION. When filling tank on side stand leaning to left do you get less fuel in tank. Normally I put bike on center stand or sit on it while fueling with bike up right. On the trip with 120lbs plus on the back of gear I left it on side stand.  Also on fuel stops I wanted to stretch legs, so side stand it was. So once it was full I would burb more fuel in and let it drain in the fuel filler stand pipe. I would get another 0.10 to 0.20 gallons in. It was not draining out vent tube or scupper tube. Normally I don't worry about topping it off to max capacity but I wanted max range. BTW the charcoal filter fell off, cough. I do believe the tank takes more fuel, at least easier, when not on side stand, either center stand or seated with bike upright. One leg of trip low fuel light came on earlier than expected. My MPG are pretty constant.  In that case I stopped fueling with first pop off of fuel pump handle. No attempt to burp more fuel in.        

[dirtrider]

10 hours ago, gmcjetpilot said:

 

Thanks Mr. Dirtrider. Fritz ran like a Champ overall not a hiccup on the almost two week trip.... from twistiness to highspeed. One question, you mean this stuff

 

 Techron .

 

I assume it is safe for rubber and all the stuff needless to say, since you would not suggest it. Cool. NAPA has best price. I'll order it now and pick it up tomorrow. I remember as a very young kid all the fas stations strived to get customers with their Techron or other additives. Also they had toys for kids, some of them pretty good, like tin metal models. I remember having something like a tow truck with name of gas brand... I wish I had it now. Might be worth some money.

 

As far as ground I remember you saying that. I check continuity but hear you. I think the issue is with the vertical tube sender internals.  I did rewire almost everything except the pig tail from the sender to the connector in the tank plate pass through. How about GROUND the sender which is exposed on top of tank?  I could easily run a wire under the fairing to ground. Brilliant idea or dumb?  First I need to determine if the metal sender housing is to ground. If adding ground helps great. I think it is the sender internal. This means fairing has to come off which is in works as I have to swap out cheap LED Fog lights for good ones. It is easier than removing the tank.

 

Taking the tank off or worse pulling the fuel pump, filter, low fuel float assembly out is a non starter.  I still have PTSD from the last go at it. Successful but I like to ride it more and work on it less. Ha ha.

 

So Techron it is. Fingers crossed. However as of now it is petty good. It is not a huge deal, I rode bikes for a long time with NO fuel level of any kind. It is just I hate things not working. If it's there I want it to work.  I can say it is pretty accurate in that it marched down in a linear fashion with miles.                        

 

QUESTION.... How does the fuel get from LEFT and RIGHT side of tank to the pickup. May be it is an optical illusion. I recall the pickup is on right side of tank inner wall. RT tank is asymmetric as left side has pocket for the glove box (radio box option) in the fairing to fit into. I suppose the back of tank is lower and left side can drain to right especially accelerating. I remember older bikes I had +40 yrs ago had a balance tube across the bottom of tank. I don't see those anymore. 

 

BONUS QUESTION. When filling tank on side stand leaning to left do you get less fuel in tank. Normally I put bike on center stand or sit on it while fueling with bike up right. On the trip with 120lbs plus on the back of gear I left it on side stand.  Also on fuel stops I wanted to stretch legs, so side stand it was. So once it was full I would burb more fuel in and let it drain in the fuel filler stand pipe. I would get another 0.10 to 0.20 gallons in. It was not draining out vent tube or scupper tube. Normally I don't worry about topping it off to max capacity but I wanted max range. BTW the charcoal filter fell off, cough. I do believe the tank takes more fuel, at least easier, when not on side stand, either center stand or seated with bike upright. One leg of trip low fuel light came on earlier than expected. My MPG are pretty constant.  In that case I stopped fueling with first pop off of fuel pump handle. No attempt to burp more fuel in.        

Morning gmcjetpilot

 

Lots of questions in one post.

 

Techron is safe for your BMW, in fact Chevron puts a little Techron in all their pump fuel so if you have ever bought Chevron fuel you have already used a little Techron.

 

BMW does sell it's own brand of fuel system cleaner (the only one they officially approve), the BMW fuel system cleaner is basically just re-badged Techron. So if you want to use BMW approved Techron fuel system cleaner just buy it from a BMW dealer.

 

The fuel gets from the one side of the tank to the other by basically flowing around the back on acceleration & leaning, at least most of it does anyhow. Some of the  BMW GS-A bikes with larger (deeper)  fuel tanks do use a  form of jet pump to actually pump fuel over from the non pick-up side. 

 

Your fuel sender tube uses isolated resistor wires so grounding the top cap does no good. 

 

I have seen resistance in about all parts of the fuel gauge circuit at one time or another. I have even seen excess resistance (even opens) in solder joints on the pump pass through plate. 

 

When you had your tank apart did you remove the fuel gauge sender tube & inspect it for having a dent in the side of the tube. If the evap. system ever plugged up, the fuel pump can pump fuel out at over 40psi,  so with a plugged tank vent that can suck the sides of the plastic tank in therefore crushing the fuel sender tube.

 

If it only sucked the tank in a little ways then it can put a smaller ding in the side of the sender tube, the sliding float can get past that small ding most of the time but every now & then it can stick & not get past the tight spot. 

 

What did your RID show when the gauge wasn't working?   (full-- empty-- or stuck where it read last? )

 

If it never reads completely full then that is almost always a resistance issue, typically on the ground side. The fuel pump & the fuel gauge sender share a ground so if the RID reads different with the engine running (fuel pump running) then you definitely have ground side resistance issues. 

 

I have even seen the fuel gauge resistance caused by resistance at the big main grounding point (top rear of engine). 

 

Try the Techron first, it the gauge still acts up then next time you have the plastics off try adding a direct ground wire between the pump pass-through plate & the brown wires at the pump pass though directly to the battery negative post. Or at least do a voltage-drop measurement between the pump pass-through plate & the brown wires at the pump pass-through to the battery negative post with engine running. 

[Michaelr11]

20 hours ago, gmcjetpilot said:

I cleaned the tank connection with "DeoxIT D5". I work on for hobby electronics, amps, ham radios, vintage tube radios. Deoxit is great for POTS and connections. I rolled emery cloth to clean both sides of connector socket and pin side. Not aggressive just a scuff, with the D5.  You can get D5 at music stores, online. Don't use WD40 if you can help it. Yes it will work but D5 is made for cleaning electrical connections. 

 

I've had great success with DeOxit D5 on MOVABLE SWITCHES, like turn signals, lights, etc. I tried it on my undertank connector, and wasn't impressed.  Went back to using CRC Electrical Contact Cleaner - or any other generic quick dry elec contact cleaner.  The contact cleaner is too harsh for switches, and I found that after a few days my turn signal switch was very difficult to move. DeOxit fixed that. Quick dry electrical contact cleaner on my undertank connection keeps my fuel gauge at 10 bars after a fill up for about 30 miles.

[Lowndes]

Everything Michaelr11 says above.

 

Deoxit says:

"Cleans, protects, lubricates, and improves conductivity".  I don't even disassemble the handlebar switches, just shoot some in there.  And, a little goes a long way and lasts all season.  Kinda like the red spray CRC Battery Terminal Protector you see on car batteries only a lighter red film.

 

On plug-in, inline connectors I put a dab of dielectric (silicone) "bulb grease".  This prevents moisture and the resulting corrosion which interferes with conductivity, plus makes the connector easier to connect/disconnect.  A one-time job that lasts forever.

[Lowndes]

Back to the topic.

 

To balance the air/fuel mix with fuel injection you have to balance the air and fuel each separately to the two cylinders.  This isn't discussed much here from what I've seen.  With carburetors it's different.

 

Balancing the air thru each Throttle Body gets is covered by Dirtrider above with the manometer.  Be sure to balance AIR thru the TB's at idle AND at several points above above idle as the air at idle is mostly controlled by the BBS, above idle balance is controlled by the throttle cables controlling the butterfly valves.  (Cleaning the tiny air passages TO and FROM the BBS thoroughly with a large spray can of carb or TB cleaner made a huge difference in the idle smoothness on both my oil heads. LOTS of deposits in the TB at only 30K, see pics below.  Do this before the balancing act above).  If your bike has a lot of miles then your TB's may have worn throttle plate shaft holes leaking outside air into the TB.  There are tiny ball bearings that can fix this.  See pic.

 

Balancing the fuel can only be done by matching the fuel delivery of the two injectors.  Fortunately, the Bosch injectors are high quality and very uniform in manufacture and fuel delivery, according to Keith Gibbons, owner operator of Injector Rehab in New Jersey  https://injector-rehab.com/ .  However there are tiny, replaceable filters on the inlet end of each injector that can pick up bebris, get partially clogged, and reduce the flow to that injector.  Also, the injectors can get deposits inside that reduce flow.

 

You can clean and check that the flow is the same yourself.  There are youtube vids on how to do it.  Or you can send them to an injector shop to have them serviced and flow tested at all RPM's.

 

Before cleaning:

 

After cleaning:

 

BBS air passage inlet and outlet around throttle plate when it is closed :

 

BBS:

 

Injector Flow Test report

 

The injector filter:

 

TB Shaft bearings:

[gmcjetpilot]

On 9/30/2023 at 10:35 AM, Lowndes said:

Back to the topic.

 

To balance the air/fuel mix with fuel injection you have to balance the air and fuel each separately to the two cylinders.  This isn't discussed much here from what I've seen.  With carburetors it's different.

 

Thanks that was the cleaning I was thinking of. I just turned 50K miles (yes I know I suck BMW riders brag about mileage and less than 6 digits is weak sauce ha ha).  I have to say after riding the bike about 2800 miles in the last three weeks.... it is running sooooooo good. Hope not to jinx's myself. The bike was not ridden for few years with dead in tank pump. I went through it front to back top bottom service, replacement of parts as needed, upgrade brakes lines/pads, cleaning, touchups... The one thing I did not do is look at or check injector TB's or clean them. I added Techtron fuel additive in tank last fill up. Will do that another tank or two. This was mostly per dirtrider suggestion to correct fuel sender reliability, which has gotten to be close to 100% (vs indication being blank), after the big ride and dozen tank fill ups. This was pre Techtron, However I am giving it a try. And anyway the Techtron fuel additive can't hurt the TB and injector ports.  Thanks again for input and pictures and information.  That will be my next project. However having too much fun riding it right now, and all indications is the TB and FI are clean enough? But I would like to check the L&R balance