BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   no power to fuel pump Empty no power to fuel pump on Tue Dec 31, 2013 8:10 pm

Rockman

avatar
Life time member
Life time member
I picked up an 1986 k100rt cheap a month or two ago. It had been parked up a while because, supposedly, the fuel pump was stuffed. I've just started trying to sort it out.

What I have found is that the fuel pump doesn't work because there is no power getting to it (green/yellow wire on the connector that goes to the tank). I've traced it back to the fuse (2nd from bottom) and from there back to the fuel relay. The fuel relay switches when I take it off and test it, but doesn't switch when connected into the circuit. So from there it looks like the problem is in the circuitry that triggers the fuel relay. There are 5 wires - a large red one from the battery - this is live like it should be, two green/red, one that go to the fuse box, and one elsewhere, and a brown/yellow that go to the ignition unit, and another one (cant remember the colour). What I think I need to know is how the brown/yellow wire is controlled through the ignition unit, as in if the ignition unit is stuffed, will this also disable the brown/yellow wire.

Of course, if I've totally got it wrong, feel free to offer advise/scorn/criticism..

    

2Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Dec 31, 2013 8:22 pm

Inge K.

Inge K.
VIP
VIP
The ignition ECU grounds the fuel pump relay coil (yellow/brown wire), when a signal from the hall sensors is received.........or a signal from the starter button.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

3Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Dec 31, 2013 9:58 pm

charlie99

charlie99
VIP
VIP
might be worthwhile checking the earth points as well

did you make the measurement from the frame to the positive wire to the tank ? or the cable which supplys earth on that same connector ?

I recon a good cleanup of the main earth cable at the battery and at the frame is always a positive start at rectifying anything electrical.

we have seen some bad relays of late ...so just a heads up


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Ono power to fuel pump Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

4Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Dec 31, 2013 10:23 pm

Arlina

Arlina
Life time member
Life time member


__________________________________________________
no power to fuel pump Eu-log10  K1100RS/LT - R1200RT - R1100RS (RIP) - Cagiva SST 350 Ala Verde
    

5Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Dec 31, 2013 11:43 pm

Rockman

avatar
Life time member
Life time member
@Inge K. wrote:The ignition ECU grounds the fuel pump relay coil (yellow/brown wire), when a signal from the hall sensors is received.........or a signal from the starter button.

Ok, I can check if it does that on the starter button. I'll also check the other side of the fuel injection relay (green/yellow on the diagrams wheeldigger posted links for). It should have power from the second fuse down from the top. I'll check the earths too. All the instuments light up, blinkers work and the starter motor works, but no headlight or oil warning light. I did check the fuel relay was actually connecting through when tripped so I think its ok.
Thanks all
Phil

    

6Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Dec 31, 2013 11:49 pm

Rockman

avatar
Life time member
Life time member
@charlie99 wrote:might be worthwhile checking the earth points as well

did you make the measurement from the frame to the positive wire to the tank ? or the cable which supplys earth on that same connector ?

I recon a good cleanup of the main earth cable at the battery and at the frame is always a positive start at rectifying anything electrical.

we have seen some bad relays of late ...so just a heads up

G'day Charlie
I checked from the positive wire to the frame and also directly back to the -ve on the battery. Cleaning earth connections is always a good thing.
cheers, Phil

    

7Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 12:19 am

charlie99

charlie99
VIP
VIP
um doesn't the pump get power from the second bottom fuse ?

worth checking
I have seen them blow ....just from being ..semi seized ..or without use for a long while

check them all


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Ono power to fuel pump Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

8Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 12:30 am

Rockman

avatar
Life time member
Life time member
@charlie99 wrote:um doesn't the pump get power from the second bottom fuse ?

worth checking
I have seen them blow ....just from being ..semi seized ..or without use for a long while

check them all

Yup, but that power comes from the battery via the fuel injection relay, which is switched on by the green/yellow and brown/yellow, and the brown/yellow is earthed by the starter switch or ignition unit, and the green/yellow gets its power from the 2nd fuse down....  Goes round and round in circles  😕

    

9Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 1:25 am

RicK G

RicK G
VIP
VIP
Phil measure the fuse with a meter I have seen many of those blade type go O/C and not show as blown.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

10Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 2:06 am

Rockman

avatar
Life time member
Life time member
Don't know what happened to my post, so I'll try again

I have success.. heres the steps

I connected a temporary jumper from the brown yellow wire at the fuel relay to earth. The relay switched when the ignition was on and I have power to the fuel pump +ve wire at the tank.
Then I pulled the spark plugs and turned the motor over. Good spark at the plugs suggesting the Hall effect sensor and ignition control unit were ok.
Next thing was to remove the connector from the back of the ignition control unit and check the brown/yellow wire was connected through to the fuel relay. All good there.
So, hoping that to was just a bad connection I put the connector back on the ignition unit and removed the temporary jumper connection. Success - relay now switches when I press the starter button and power gets through to the fuel pump wire. Voltage is a little low at 11.5v, but the battery is down a bit too.

Tomorrow I'll clean up all the connections involved and put the tank off my other K100 on this one and see if it goes Very Happy

    

11Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 2:55 am

charlie99

charlie99
VIP
VIP
so a brumby socket on the relay carrier phil ?

or the ecu pinout ?

good find

I just did my solenoids on the door locks of the rolla today
would activate sometimes
also female spade connectors of the plug, male spades on the solenoid socket

I used fingernail sanding boards ...(cheep as from the discount shops ) cut a little to size, to get into the spade females and get the crud off ...likewise with the solenoid side
some cleaner then the deoxit gold to condition the connectors
nice strong pull now


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Ono power to fuel pump Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

12Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Jan 01, 2014 6:17 pm

Rockman

avatar
Life time member
Life time member
@charlie99 wrote:so a brumby socket on the relay carrier phil ?

or the ecu pinout ?

good find

I just did my solenoids on the door locks of the rolla today
would activate sometimes
also female spade connectors of the plug, male spades on the solenoid socket

I used fingernail sanding boards ...(cheep as from the discount shops ) cut a little to size, to get into the spade females and get the crud off ...likewise with the solenoid side
some cleaner then the deoxit gold to condition the connectors
nice strong pull now

ECU pinout. The connections actually look quite clean. Must have had a thin coating of crud. Evidence the bike has been near the seaside so it looks like I should unplug, clean and remake all connections. Obvious really.

    

13Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Thu Jan 02, 2014 6:12 pm

Rockman

avatar
Life time member
Life time member
No go with getting it to run. Strange happenings with the electrics. Power at connector near the tank has gone, except occasionally. Then I get an odd effect when I check it with a multimeter. With everything off the meter holds at -12.6 volts (not +12.6!) and lowers gradually to zero. Some sort of induction effect? Dunno. Anyway, no more time to play with this so I'll park it up for a while. And I though old jap electrics were a pain.

    

14Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Sun Jan 05, 2014 5:32 pm

Toto_jp

avatar
Platinum member
Platinum member
Could it be a dodgy relay ?
the points inside may have welded together at sometime
and now can't hold together /allow enough power thru 
Smile hope its something as simple

cheers Tony


__________________________________________________
K100 RS 1986
    

15Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Sun Jan 05, 2014 6:22 pm

Rockman

avatar
Life time member
Life time member
@Toto_jp wrote:Could it be a dodgy relay ?
the points inside may have welded together at sometime
and now can't hold together /allow enough power thru 
Smile hope its something as simple

cheers Tony
Could be something simple and probably is. Dodgy relay, dirty connection etc. I've just about resolved to pull all the electrics apart, clean all connections and check everything. The plan is to semi restore this bike anyway, so I might as well do it properly rather than trying to cut corners.
cheers, Phil

    

16Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Tue Jan 07, 2014 2:33 pm

acftfliehr

acftfliehr
active member
active member
Check the pesky crappy ignition switch and kill switch...  These can cause big problems by making intermittent connections due to arcing and corrosion.... causing all sorts of intermittent operations...

Here is how to clean it...

I've used Don Eilenberger's post which is excellent with pictures etc....

<http://www.eilenberger.net/K75S/IgnitionSwitch/ >

Also, years ago, on my 1985 K100, the fuse that powered the fule pump (and other items I believe) was blowing intermittently...   found the power wire inside the fuel tank was chaffed thru to at the tank vent aluminum line inside the tank...  I repaired it and covered with alcohol resistant sleeve, and tie wrapped it to a stand off from the line...

This doesn't sound like your problem as the fuse blown is the smoking gun!!

    

17Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Sun Dec 13, 2015 4:14 am

Mark K Boy

Mark K Boy
Gold member
Gold member
Thanks guys.
The thread may be old however the info is still good.


__________________________________________________
Mark Surman
Keep the shinny side up !

no power to fuel pump Au-log12
http://www.marksurman.com
    

18Back to top Go down   no power to fuel pump Empty Re: no power to fuel pump on Wed Dec 23, 2015 5:01 pm

Mark K Boy

Mark K Boy
Gold member
Gold member
Update:-
In my case a bad side stand switch.

The lesson - its not enough to check to connector block but to check the operation of the switch as well before looking for a deeper problem.

For the K11 guys some easy reference.

no power to fuel pump 853c1e0071f336506e9f23d4ead0d882

no power to fuel pump 26973618afee5fe6049d63edf8b633a1


__________________________________________________
Mark Surman
Keep the shinny side up !

no power to fuel pump Au-log12
http://www.marksurman.com
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum