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1Back to top Go down    Wont start.................. on Sun Sep 29, 2013 4:31 am

MXI

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Very odd, got this bike a week ago and its been ok. Been out a few times and nothing to say it had any problems. Went to start it today and it just wont start.

Symptoms - Well you push the button and it turns (Even starts to bite at the very first push) but no actual startingaffraid. Heres the proof



No looking around some youtube vids and most seem to whine before the button is pushed, this appears to be the fuel pump putting pressure into the fuel system, mine does not, but you can hear the fuel pump running for a second after.

I confess I am lost, my other bikes are simple carb fed aircooled things, this is all electrics.

Any ideas?

    

2Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 5:03 am

charlie99

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buy about 10 seconds in.... the pressure should have come up on the fuel pump and the noise changes

could it be that there is some blockage on the intake .....or the fpr isn't holding pressure ...or there is a fuel feed line issue inside the tank ...

we have seen a few times that the internal fuel lines have deteriorated letting the fuel back into the tank instead of down the injector line
?
check around the fuel filter ?


just a thought


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3Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 5:27 am

RicK G

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On a K100 8v the fuel pump will start when you push the starter button and not before but on a 16v it will run when you turn the key on or the kill switch on. That may be where you are getting the difference.
The problem you are having sounds like a lack of pressure try what Charlie99 has suggested and it's probably a good time to put new fuel lines on but get the correct line, the one that is able to stand being imersed in the fuel.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

4Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 5:33 am

MXI

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@charlie99 wrote:buy about 10 seconds in.... the pressure should have come up on the fuel pump and the noise changes

could it be that there is some blockage on the intake .....or the fpr isn't holding pressure ...or there is a fuel feed line issue inside the tank ...

we have seen a few times that the internal fuel lines have deteriorated letting the fuel back into the tank instead of down the injector line
?
check around the fuel filter ?


just a thought
Rick,
Thanks so much for that it really does help, so I shouldnt get the whine before hand. Didnt think it did before but you know you look on the tube and the vids are there, then the seeds of doubt.

Thanks so much for your help. As you can hear in the first vid the pump only runs when you hit the switch and for a second or two after. I have taken a vid of the pipes and in the tank, it looks very nice and clean.

Scares the hell out of me that there are two wires to the pump nice and open in all that flammable liquid. YIKE!!!!!!!!!!!!!!!

So (And I am sorry, total numpty and newbie on this bike) where is the FPR and what is it. How do I check the other stuff, on my other bike you can check that kind of thing as it would leave a puddle, bit more complex in the tank.

Heres the inside tank vid.



Gonna have to wait till next week unless I get time later. Could the filter be at fault?

    

5Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 5:45 am

RicK G

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Get a gauge and check the fuel pressure it should be 2.5bar at the injectors and if you crimp of the return line it should go to 4.5bar or maybe even 5.
If when you crimp the return line you getvery low or almost no pressure the pump and inside the tank is where to look and if there is no pressure before you crimp the line and it goes to 4.5 then the Fuel Pressure Regulator is the problem
The FPRs have proven to be reliable but we have seen a few fail recently so maybe the life span is 25 to 30 years.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

6Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 2:25 pm

MXI

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Rick, you clearly have loads more knowledge than me. Sorry

What gauge?
How to crimp
What return line

Really sorry.

    

7Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 3:43 pm

92KK 84WW Olaf


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@MXI wrote:Rick, you clearly have loads more knowledge than me. Sorry

What gauge?
How to crimp
What return line

Really sorry.
No need to be apologetic, we all start somewhere.

Far more respect for the man who askes the proper question as you didinstead of proceeding blindly into oblivion.

You do have one or two other options but some will say its spending money rather than solving the problem but it avoids the purchase of a gauge if you haven't got one and keeps it simple. You probably are unlikely toneed a gauge much after this job is done.

Charlie 99 and Rick G seem to suggest the fuel tank. So would I. The pipes inside the tank if original should probably be replaced anyway. Similarly if you don't know the history of the fuel filter that should be done too. But you need to be sure the inside of the tank is clean so no dirt comes up to block it. When they are done then you will also see the pump is working [or not working] and that should eliminate possibility of the cause being inside the tank. Those two items are very high on the suspect list and are relatively small money but just take a little time. The fuel pump itself is also a possibility and if there is a problem with it that will show up now.Once these are done you should not need to be back at the tank for quite a long time. If you are already fully happy with the tank then you could go straight for the FPR below, but it seems the tank is the more likely source of the problem.

If when they are done and you still have a problem then you have one other item, the fuel pressure regulator [FPR]. You should come back here before doing it. As far as I can see its located between the airfilter box and intake manifolds so its the fiddly one to get at requiring removal of the fuel tank and top of the airfilter box. You need to be careful here as there is a delicate part inside the top of the box, you will see wires on top of the box.If you are replacing the FPRyou should replace the fuel lines, the manufacture date is stamped on BMW ones and you should use BMW fuel line. They perish in time and the fiddling around is likely to end their lives. Fuel lineis cheap, I have plenty spare here as do most of us. An FPR is also easy to pick up.

If you can you should get a Clymer manual as it is very good.

Just a little word, my 84RT has the power connection to the fuel pump at the front left of the tank, its a 4 pin that goes in underneath. It was dodgy and gave me similar symptoms. Try wriggling it to see if any effect, if it does you can crimp up the connections slightly to resolve it and it will click back into place.


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1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 83,150miles
    

8Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 5:22 pm

MXI

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I am gonna work through that. However at the moment I have a big empty room where my kitchen should be so it maybe a week or two.

Thanks for you help though. I can use my other bike for a while

    

9Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 9:00 pm

RicK G

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My place to appologize there I tend to assume others have knollege of many of the things I do and often talk over their heads.
If you PM Crazy Frog and get a password for the downloads section there are many things there that you wont need to purchase. also a flow chart on trouble shooting your not starting problem.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

10Back to top Go down    Re: Wont start.................. on Sun Sep 29, 2013 10:33 pm

Rabidchiwawa007

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You can also press the starter button while you WATCH all of the fuel line connections. If any of the lines move back when the pump is on and then forward when the pump turns off, you've got pressure leaks. This wouldn't really cause it to not start unless it's really bad, so if that was the case, it'd likely be inside the tank.

You could check the injector spray as well. Just pull the fuel rail off, press the start button briefly, and look for spray out of the nozzles.

Check the spark plugs as well if you haven't. The only electrical thing I could think of it could be is the spark. Other than that, it just sounds like a fuel delivery problem.

Fuel:
-check / replace fuel filter (cheap)
-check / clean / replace fuel pre-filter (on bottom of fuel pump)
-check / replace fuel lines and connections (cheap)
-check injectors for spray / clean injectors / replace if necessary
-check / replace fuel pressure regulator (eh.. not expensive..)
-you can also check the fuel pump pressure by doing the following if you do not have a gauge:
--remove the fuel line from the inlet of the fuel filter
--cover the line with your thumb firmly
--press the starter button
--if you cannot hold your thumb in place against the fuel pressure, the pump is likely okay, or at least wouldn't keep the bike from starting.

Air:
-sort of silly, but make sure air is getting to the engine... air filter? anything else?

Spark:
-check plugs / gap / clean / replace if necessary (cheap)
-check for spark.. pull plug out, connect to plug wire, ground against engine, press starter, look for spark (use rubber-handled pliers or something, and make sure there're no gas leaks.
-if no spark, plug wires? coils? coil leads?


Hope this helps.


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