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Discussion Starter #1
Hi all. Old member re registered.
My old K1200LT (2000) model was sitting for last 4 weeks - running sweet as until today....
Went to start and she just turned over not even attempting to fire - nice. So off with right side panel and air filter horn - squirt of car cleaner hit the starter and fires up -but still wont run without the juice.
So off with left side panel and out with the plugs - dry. New set of plugs - turns over but not firing. OK so guess the fuels gone off - drained tank after checking the pump was pushing out the hose and 2 gallons of new fresh fuel. Still not starting.
So of with the tuperware and off with the tank - fuel filter is perfect.
The pump however is another matter.
When it's plugged into the loom turn the ign on and the pump runs for 1 or 2 seconds - that cant be right - if the pump is not getting pressurised it should keep on running until turned off - right? Thats what normally happens with fuel injection systems - the pump runs until it gets push back pressure then stops until engine is running.
So symptoms: ign on - pump runs for 1/2 seconds and stops - regarless of whether it has back pressure or not so in effect no fuel being pushed upto injectors.
Can it be just the pump is stuffed or is there something in the elctronics that would stop the pump from running on?
 

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Hi all. Old member re registered.
My old K1200LT (2000) model was sitting for last 4 weeks - running sweet as until today....
Went to start and she just turned over not even attempting to fire - nice. So off with right side panel and air filter horn - squirt of car cleaner hit the starter and fires up -but still wont run without the juice.
So off with left side panel and out with the plugs - dry. New set of plugs - turns over but not firing. OK so guess the fuels gone off - drained tank after checking the pump was pushing out the hose and 2 gallons of new fresh fuel. Still not starting.
So of with the tuperware and off with the tank - fuel filter is perfect.
The pump however is another matter.
When it's plugged into the loom turn the ign on and the pump runs for 1 or 2 seconds - that cant be right - if the pump is not getting pressurised it should keep on running until turned off - right? Thats what normally happens with fuel injection systems - the pump runs until it gets push back pressure then stops until engine is running.
So symptoms: ign on - pump runs for 1/2 seconds and stops - regarless of whether it has back pressure or not so in effect no fuel being pushed upto injectors.
Can it be just the pump is stuffed or is there something in the elctronics that would stop the pump from running on?
The pump prime cycle for a few seconds and then a shut off is normal. That presurizes the fuel rail and then it waits to sense pulses from the hall sensor on the crank shaft indicating the engine is turning. It is a safety feature so that in the event of a crash, it doesn't continue to pump raw fuel onto a hot engine if there was damage once the engine stops.

The most likely thing that has happened is that you ruptured one of the lines inside the tank. Not unusual for a bike that age. There are several ways to check for this. One is to look inside the fill hole and towards the back to look for any large disturbance of the fuel in the tank indicating a burst line. If you still have the side panels off, you can remove the level sensor tube and visually inspect them. Be careful if you turn the key on doing this as it could spray fuel into your face if one has burst.

Welcome back to the forum Bob.
 

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Discussion Starter #3
Hi. Thanks for speedy reply. Hoses in tank are all good - pump assy now removed.
Assuming the start cycle of pump is limited to 2 seconds - how does that prime the system when there is no fuel in it? Most cars/motorcycles etc - when ign turned on will pump enough to get back pressure from the line then shut off - this can normally be heard as a fast-slow gurgling - especially when priming a system.
In this case the 2 secs is not enough to get fuel upto injectors buth the line is pressurising as can be heard when disconection the feed pipe and a release of air pressure is heard.
Is there something else in the system that will stop the fuel getting to injects from pump?
Cheers
 

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Hi. Thanks for speedy reply. Hoses in tank are all good - pump assy now removed.
Assuming the start cycle of pump is limited to 2 seconds - how does that prime the system when there is no fuel in it? Most cars/motorcycles etc - when ign turned on will pump enough to get back pressure from the line then shut off - this can normally be heard as a fast-slow gurgling - especially when priming a system.
In this case the 2 secs is not enough to get fuel upto injectors buth the line is pressurising as can be heard when disconection the feed pipe and a release of air pressure is heard.
Is there something else in the system that will stop the fuel getting to injects from pump?
Cheers
2 seconds is plenty. It is a closed system and very short fuel lines that are already full of fuel.

If it runs on starter fluid/cleaner but not without, most of the systems are working. Hall sensor. spark plugs etc. Does sound like a fuel system issue. You can test the hall sensor by putting it up on the CS and in 5th gear. Turn on the key, wait for the prime to complete and turn the rear wheel with your foot slowly. As the hall sensor moves, it will turn on the fuel pump. You can hook up a meter to it if you still have everything removed and you should see it apply and remove voltage to the pump, assembled, you would hear the pump cycle. I think that is OK as I believe that also times the spark which seems to be working as in running with starter fluid.

That leaves the pump, filter and pressure regulator to be having an issue. The only way to test the pump is to put a pressure gauge on it and see if it can generate any pressure. They are a constant flow type and can generate in excess of 50psi when dead ended. The system runs at about 50psi. If the regulator has failed, it would not be able to generate any pressure in the lines, again, an inline test would show the lack of pressure. If you don't have quick disconnects, there is a coupling that could have a T fitting put in and a pressure gauge attached to test for pressure and also flow. Lastly is the filter. It could be clogged or if any water got in the tank, that would plug the filters paper element and prevent fuel flow. If water was present for some reason, the filter would need to be replaced.

If the injectors are not firing but the plugs are, It could be the motronic but they don't have a history of going bad. They all fire at the same time according to the schematics wiring. I don't see a fuse in that circuit to check.
 

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Wrencher Extraordinaire
2005 K1200LT
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If you have quick disconnects make sure they are seated as they do close when removed. If you don't have QDs make sure you have the hoses hooked up correctly. Fuel will not go backwards through the regulator. If you are worried about 2 seconds not enough time just cycle the kill switch with the key on it will run (for 2 seconds) the pump every time.
 

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As John said, you can cycle the kill switch and you should hear the pump run for a few seconds every time you move it to the run position. Keep in mind that if the hall sensor is being sensed, as you crank the engine, it will engage the pump as you crank the engine. Doing the hall sensor test will let you know that the pump is being engaged during cranking and the kill switch can be used to cycle the pump if you manage to get a pressure gauge hooked in line or dead ended on the pressure side.
 

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Discussion Starter #7 (Edited)
Thanks for the replies folks.
So here I am on Sunday - just spent 4 hours on the BLEEP! took 6 attempts to get fuel pum resealed.
Anyway....
- New battery
- New fuel filter & proper clamps - all good including hoses & pressure tested before setting back in tank
- Tank reattached and hoses
- 2 x galls new high octane fuel
- TPS reset - didnt do this before after changing battery
- Cycled ign/fuel pump 3 times before attempting to start - nothing - just turning over
- Recheck spark - all good
- Removed plugs again - all dry - so assume no fuel
- Open tank look inside and turn key - slight bubbling obviously from the return pipe - nothing dramatic
- Insert fuel pressure gauge after tank before press regulator - get initial burst when key turned of 90psi - drops to 42 - turn off key - then quickly to 34 then gradually to 20psi where it stays. No leaks anywhere visible - tested this by cycling ign 5 times to see if anything would pop at higher psi.

So there we have it - is this proof the pump is stuffed? Question now is at what pressure do the injectors open? If it's lower than 50psi I keep reading about what is the lowest it will operate at?
Has anyone rigged up an external electric pump to test? ie have the intank outlet pump going to an external fuel tank and use an external fuel pump/tank to feed the injectors?
 

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Thanks for the replies folks.
So here I am on Sunday - just spent 4 hours on the BLEEP! took 6 attempts to get fuel pum resealed.
Anyway....
- New battery
- New fuel filter & proper clamps - all good including hoses & pressure tested before setting back in tank
- Tank reattached and hoses
- 2 x galls new high octane fuel
- TPS reset - didnt do this before after changing battery
- Cycled ign/fuel pump 3 times before attempting to start - nothing - just turning over
- Recheck spark - all good
- Removed plugs again - all dry - so assume no fuel
- Open tank look inside and turn key - slight bubbling obviously from the return pipe - nothing dramatic
- Insert fuel pressure gauge after tank before press regulator - get initial burst when key turned of 90psi - drops to 42 - turn off key - then quickly to 34 then gradually to 20psi where it stays. No leaks anywhere visible - tested this by cycling ign 5 times to see if anything would pop at higher psi.

So there we have it - is this proof the pump is stuffed? Question now is at what pressure do the injectors open? If it's lower than 50psi I keep reading about what is the lowest it will operate at?
Has anyone rigged up an external electric pump to test? ie have the intank outlet pump going to an external fuel tank and use an external fuel pump/tank to feed the injectors?
42 would probably be an acceptable pressure and it should run at that pressure. It might even run at 20 but probably not very well under a load. While cranking does it stay at 42 as the pump should run while the engine is turning?

Is there anything else that you did after the bike sat for 4 weeks? No maintenance of any kind just turned the key and no run.

Do you have mice? :) Is it possible some varmint chewed through some wires?

Fuel pump relay looks to power both the pump as well as the injectors so if the pump is running, the injectors should have power baring any bad wires. You might be able to check that with a meter on one injector plug. The injectors ground through the ECU on pin 20 on yellow/grey wires and as I stated before, it looks like they all should fire at the same time in parallel so if one doesn't work, none of them will. Power should be on the green/white wires on the injectors.

Other than starting to trace and check wires, I am not sure where to direct you next if the pump is making 43PSI while turning.
 

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Discussion Starter #9
Everything seems to check out....
When cranking the pressure goes to 80/90 psi then when left standing, stationary pressure is 40 and descends to 25 and a bit lower over time - that seems to me like normal ie it has more than enough at crank to tell inj to open.
Begining of story: Rear stop light jammed on so had to remove tank to replace relay. After reassembly bike fired straight up and idled for 10mins no problem. Left battery connected for few weeks and started again no probs. 2 more weeks and battery had died - so fitted new one and then the non start issue surfaced.
So somehow, somewhere it's develped a no fuel issue without any outside interference.....
 

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2011 R1200RT
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just a thought, but... when you installed the new fuel filter, is it possible you put it in backward?
 

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2005 K1200LT
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You should never see 90 PSI if your gauge is between the pump and the FEED side of the fuel rail (front end). The regulator is on the return end (rear) of the fuel rail. I suspect you have your hoses crossed since fuel will not flow backwards through the regulator.
 

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You should never see 90 PSI if your gauge is between the pump and the FEED side of the fuel rail (front end). The regulator is on the return end (rear) of the fuel rail. I suspect you have your hoses crossed since fuel will not flow backwards through the regulator.
I second John. The regulator should limit the pressure to ~50 psi. If you are seeing 90, it sounds like you are dead heading the pump. Does your LT have quick disconnects? If not, then it would be easy to cross the connections.
 

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Your statement of :
"Open tank look inside and turn key - slight bubbling obviously from the return pipe - nothing dramatic"
caught me. This usually means a split hose in the fuel tank, but you said they were good. If the fuel disconnects are both aligned in the same direction, I would try switching them just to see if it fires up. Nothing to lose.
 
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Everything seems to check out....
When cranking the pressure goes to 80/90 psi then when left standing, stationary pressure is 40 and descends to 25 and a bit lower over time - that seems to me like normal ie it has more than enough at crank to tell inj to open.
Begining of story: Rear stop light jammed on so had to remove tank to replace relay. After reassembly bike fired straight up and idled for 10mins no problem. Left battery connected for few weeks and started again no probs. 2 more weeks and battery had died - so fitted new one and then the non start issue surfaced.
So somehow, somewhere it's develped a no fuel issue without any outside interference.....
Bob, where are you with this? Did you validate your hoses are connected correctly after jzeiler caught the 90PSI as being incorrect something you should not see unless the lines are reversed? Pictures of the hoses proper position are in post #5
 

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Discussion Starter #17
Solved 2 hours ago - yes it was the hoses but not what you think......the feed pipe had collapsed internally (can only assume a bubble/bad patch during manufacturing many years in the past had finally gave way) and the interior wall was creating a blockage and therefore increased the pressure during cranking. Only found it after striping everything back off to start from scratch and got it in 5 mins. What in PITA to get to this point but all is good and starts off the button as sweet as.
Many thanks to all for your help.
Bob
 

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2005 K1200LT
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That explains the sudden appearance. I had seen that in brake lines that would not release the brakes but in a fuel line is new to me. Just glad you found it!
 
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