fuel pump-i think , Advice please....

[sasazgorelec]

another hello from Croatia ....
i need an advice..
Yesterday i syncronised tb, and adjusted the valves with a help of a guy who serviced BMW in Cro. untill 2001.After we started it up it was fine......not...... very fine, and after we think that it is a time for a test drive ..it went off....
The fuel pump run and it wouldn't stop (we notice that after a several tryouts to start the engine).....
We dismounted the fuel injectors and tried to start so we can see if the fuel is gettin to the injectors-NOTHING..
i thote that the fuel filter is jamed so we took everything appart,fuel filter ok -nothing jamed or so.
one thing do--the fuel pump had the strangest noise, it was like it was no fuel(run dry) noise, but the tank had 10l....

Now the imprtant thing.... after all te sevice and the motor running i had a grey smoke out, and it was rich with unburned fuel, you could smell it( like it had too much fuel and it couldnt burn complitley).. that happen before, when you started it it was ok, and then after a few minutes it started to smoke and smell, sometimes litle ,sometimes allot , sometimes nothing (after a good run)...

My question...

Did the fuel pump start to lose the presure and finaly broke, so i need to replace it and the smoke will disapear and the motor will start?

... or there is something else .......more deeper mater involved?

Many thanks....guys for each and every post.....it helped

[CycleRob]

The TB synch should be done AFTER the valve adj, but that is not the cause of your running problem. For that, check the basics:

--Reset the Motronic memory by removing and replacing fuse #5, then cycling the throttle from 0 to 100% two times with engine off + key (+KillSw) on.
--Check that fuel line QD's are completely pushed together and the metal push-to-release tab is sticking out.
--Check that the electrical plug from the fueltank to the bike's bracket mounted electrical power plug is fully connected.
--Check that vacuum lines, or spigot caps are plugged on below both TB's after you did the TB synch.
--Cycle the sidestand up/down/up/down several times and try starting the engine.
--Cycle the KillSwitch on/off/on a few times and try starting.
--In the row of the small black rectangular relays (those that are the same size), in the junction box under the seat, swap the first two with the third and fourth ones. They are all the same size and configuration (just rotated a half turn). After the 1&2 relay swap for relay 3&4 "the problem" relay will move the malfunction to the horn and lights.

If all that fails, you may need the expertise of a BMW dealer -or- a good local mechanic with test equipment and experience with modern fuel injected engines. You may also actually have a Hall sensor or fuel pump failure, but TESTING them is preferred to to REPLACING them.

Good Luck!!

[boxermania]

Hmmm,

Hard to even guess at what is the problem, need more information.

1) Was the bike running OK before the adjustments?
2) Did the valves require a lot of adjustment?
3) Is there any compression? I'm trying to see if the valves were adjusted away from TDC.
4) Have you check if the plugs are firing?

If the injectors are firing (electrically) and there is no spray, the pump is not working, or something is plugged in the system.....even if the pump is operating at a reduiced pressure there should be a small amnount of fuel leaving the injectors.

Hard to tell what is the problem

[allanj255]

Good advice CycleRob. I will keep this for future reference.

[Eddiem]

Cycle Rob is the man, he knows so much about these boxers it is amazing...the more I read about this items the more amazed and impressed I'm with you Rob!

I will also keep this info handy....very good diagnostic and inteligent analysis.

Aloha!

EM

PS: BTW thanks for your help!

[Capt. Blackadder]

I may be wrong, but it sounds to me like the fuel line quick disconnects are not completely pushed together. If that's the case, the no-spill closing mechanism inside them is still closed, not allowing fuel to flow. The fuel pump strains against that blockage, sounding funny in the process. No fuel reaches the fuel pressure regulator, so the fuel pump doesn't get shut off when proper pressure is reached. When you started the motor after the service, the motor started up and ran for a little while, using the fuel in the line downstream of the quick disconnects, and then shut off from fuel starvation.

Take the quick disconnects apart again and first check for any damage to the little O-rings and any debris inside the quick disconnects. If they're fine, lubricate the little O-rings slightly, either with saliva or a very thin film of vaseline. When re-assembling, align them very carefully, making sure the O-rings don't bind, and push the quick disconnects together carefully but firmly, making sure you hear a little 'click' sound.

Now switch the bike on and off a couple of times to see if the fuel pump turns on and then off. If it does, start the bike up and check for any fuel leaks. Hopefully this helps, and good luck.