west coast traveller
Registered user
Worth checking 12v supply and earth then...I would imagine that the pulse from the motronic either works or it doesn't.
Thanks
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Losing power
- Thread starter west coast traveller
- Start date
Worth checking 12v supply and earth then...I would imagine that the pulse from the motronic either works or it doesn't.
Thanks
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west coast traveller
Registered user
Update......
Not done much since last post till today. New fuel pump (not BMW part) and filter) replaced today and guess what...? no sodding difference- spitting popping rough running and cutting out. Nearly put a match to the whole lot!! After composing myself checked injectors again and all seemed fine but decided to have a look at what was coming out of the return pipe. Undid the QR joint and turned engine with the intention of opening the QR non return valve to see what was coming there.............as soon as I turned engine on bike ticking over smoothly and reving to the limit as it should (this was with pipe disconnected without opening valve). Connected pipe back up and bike ran smoothly for about 30 seconds then back to running rough. Disconnected pipe again and... voila! running perfectly.
So, my guess would be that the fuel regulator valve is shot and needs replacing. However, I would be interested if anyone has similar experience and what caused it before I order the part. Thanks in advance for any ideas.
Not done much since last post till today. New fuel pump (not BMW part) and filter) replaced today and guess what...? no sodding difference- spitting popping rough running and cutting out. Nearly put a match to the whole lot!! After composing myself checked injectors again and all seemed fine but decided to have a look at what was coming out of the return pipe. Undid the QR joint and turned engine with the intention of opening the QR non return valve to see what was coming there.............as soon as I turned engine on bike ticking over smoothly and reving to the limit as it should (this was with pipe disconnected without opening valve). Connected pipe back up and bike ran smoothly for about 30 seconds then back to running rough. Disconnected pipe again and... voila! running perfectly.
So, my guess would be that the fuel regulator valve is shot and needs replacing. However, I would be interested if anyone has similar experience and what caused it before I order the part. Thanks in advance for any ideas.
Fluffy Misfire
Good Day,
I have a very similar problem on an 03 twinspark GS, that has been driving me batsh!t for about two years , so much so that it is about to get traded in or set on fire.
The bike will run fine until about 4500-5000 (70 - 80), when it will start to splutter and misfire (run fluffy sums it up) sometimes it will run through to 120, but still rough (not tested on public roads) . I have changed the stick coils, the ECU, the lambda sensor (after a visit to Steptoe showed it to be faulty), swapped out the injectors, changed the airbox sensor. The TPS is set spot on at idle according to Steptoe's diagnotic tool.
The bike seemed slow to crank and initially would not crank until I removed and cleaned the starter. Next component to change is a second hand TPS, in case the TPS is out at higher revs.
Does anyone have any other ideas? I also have an ECU if anyone needs one.
You mentioned disconnecting the QR, which one did you disconnect.
Did changing the fuel regulator work?
Cheers
Good Day,
I have a very similar problem on an 03 twinspark GS, that has been driving me batsh!t for about two years , so much so that it is about to get traded in or set on fire.
The bike will run fine until about 4500-5000 (70 - 80), when it will start to splutter and misfire (run fluffy sums it up) sometimes it will run through to 120, but still rough (not tested on public roads) . I have changed the stick coils, the ECU, the lambda sensor (after a visit to Steptoe showed it to be faulty), swapped out the injectors, changed the airbox sensor. The TPS is set spot on at idle according to Steptoe's diagnotic tool.
The bike seemed slow to crank and initially would not crank until I removed and cleaned the starter. Next component to change is a second hand TPS, in case the TPS is out at higher revs.
Does anyone have any other ideas? I also have an ECU if anyone needs one.
You mentioned disconnecting the QR, which one did you disconnect.
Did changing the fuel regulator work?
Cheers
Last edited:
west coast traveller
Registered user
Morning. I disconnected the return QR connector. On my bike this is the top pipe of the 2. If you have disconnected the feed pipe from the pump the bike won't start. I'm putting the new regulator in on Monday so will let you know what happens. Good luck.
west coast traveller
Registered user
Good Day,
I have a very similar problem on an 03 twinspark GS, that has been driving me batsh!t for about two years , so much so that it is about to get traded in or set on fire.
The bike will run fine until about 4500-5000 (70 - 80), when it will start to splutter and misfire (run fluffy sums it up) sometimes it will run through to 120, but still rough (not tested on public roads) . I have changed the stick coils, the ECU, the lambda sensor (after a visit to Steptoe showed it to be faulty), swapped out the injectors, changed the airbox sensor. The TPS is set spot on at idle according to Steptoe's diagnotic tool.
The bike seemed slow to crank and initially would not crank until I removed and cleaned the starter. Next component to change is a second hand TPS, in case the TPS is out at higher revs.
Does anyone have any other ideas? I also have an ECU if anyone needs one.
You mentioned disconnecting the QR, which one did you disconnect.
Did changing the fuel regulator work?
Cheers
Finally got round to working on bike today. Changed the fuel pressure regulator and bike now running like new. Not sure whether disconnecting the return pipe would diagnose the problem on every occassion but worth bearing in mind. Anyway, back on the road again.
Stewart H
Registered user
Finally got round to working on bike today. Changed the fuel pressure regulator and bike now running like new. Not sure whether disconnecting the return pipe would diagnose the problem on every occassion but worth bearing in mind. Anyway, back on the road again.
I think the regulators fail "open" so preventing enough pressure at the injectors, by splitting the return line you allow pressure to build up due to the self closing valve, I believe one test for a failed regulator is to clamp the return line, again to allow pressure to rise, glad you got it sorted
west coast traveller
Registered user
I think the regulators fail "open" so preventing enough pressure at the injectors, by splitting the return line you allow pressure to build up due to the self closing valve, I believe one test for a failed regulator is to clamp the return line, again to allow pressure to rise, glad you got it sorted
That'll be it then,cheers.
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