1150 GS Wont Start. Possible Fuel Pump

[Blasterwizard]

When I checked the contacts 1 & 2, y obtained 12 v for a second too. Maybe its right now.

I think it can be for the fuel pressure. Don´t now exactly how it works, but, when you switch on the bike, you can ear the fuel pump until it have the right pressure, and then it stops. Soooooo may be that as it don´t have pressure reading, it desconect after a second.

Probably when you put the tank again (and conects the fuel lines) it will work.

 

[skywalker]

When you switch the igntion on does the fuel pump "whirr" intially and then goes off? If yes the problem is else where. When turning the bike over on the button can you hear the fuel pump ? If no chances are its the hall sensor especially if you've experienced the tacho needle having a mind of its own and also a noise sounding like a huge electricity spark occasionally.
On intially turning the ignition switch on the motronic unit briefly earths the fuel pump relay then relys on the hall sensor signal after that. I'm assuming you've checked fuse 6 for integrity etc ??
Has the bike got a performance chip in the motronic ? here again that could be the issue.

 

[Ian J Hartley]

So I cleaned the connections which looked perfect to me and now I can have the relay in place and get 12V at the lambda connector and fuel pump connector. But only for one second and then it goes low again. Is this a feature of the bike or do I still need to keep looking for my problem?

It may well have been doing this earlier as my testing wasn't quite as thorough and to tell you the truth I am not sure at all of what I am looking at. But its keeping me out of trouble at the moment.

Yes. You will only have 12v briefly whilst the fuel pump primes, after a few seconds the motronic shuts down and powers off the fuel pump relay. Put your finger on the relay, you should feel it click when you turn ignition on (closing) and after about 2 seconds you should feel it click again as it opens.

 

[richierex]

Well I`m off to bed.

 

[B4ndit]

Tank back on. No action.

Going to print off Steptoes instructions and see how I get on with that.

 

[(RIP) DitchWater]

Well I`m off to bed.

I was already asleep.

Perhaps it's to time to see the if the pump can push any fuel out of the end of the injectors. That's alot easier to do that taking the bike apart and trying to diagnose the minutiae of the bike's control systems.

 

[B4ndit]

Forget all the testing bollox posted so far - lets get back to proper old fashioned simple fault finding.

Feed your fuel pump directly with 12v and keep it running, turn ignition on and press the starter and see if it starts.

If it does start the problem can now only be in one place - If it doesn't start you have two items to check.

I'll let you work out what and which parts, it'll help in your diagnostic education.

It fired straight away. Better than ever.

 

[(RIP) DitchWater]

Excellent.

"Setting multimeter to ohms Captain"!

 

[Steptoe]

It fired straight away. Better than ever.

Simple. Now you know what it is ..... No, I'm not telling you, you have to do some of the working out yourself otherwise it's all wasted.

 

[B4ndit]

Simple. Now you know what it is ..... No, I'm not telling you, you have to do some of the working out yourself otherwise it's all wasted.

Your a tease.

 

[B4ndit]

Confirmed I have earth from tank so that rules out the gear cut out.

Reset Motronic. No difference.

Read lots and lots on the web which really hasn't helped.

Read the Haynes manual and from the circuit diagram it looks like the Motronic unit might be the problem.

The lambda sensor is possibly involved in this in some way but known faults aren't stopping the fuel pump (As far as I am aware)

Off to work now. Lets see what another day brings.

 

[MikeO]

Stupid question - you haven't got an immobiliser or alarm fitted, have you?

Mike

 

[Ian J Hartley]

Confirmed I have earth from tank so that rules out the gear cut out.

How did you check that. Just because the fuel gauge is working, doesn't necessarily mean you have a good ground to the fuel tank. The fuel gauge is low current. A poor earth would only show up if you put a high current through it like a fuel pump.

Read the Haynes manual and from the circuit diagram it looks like the Motronic unit might be the problem..

What makes you think that! The bike runs better than ever when you jump to the fuel pump. That has to rule out everything. Apart from the fuel pump wiring. The fuel pump relay has got to be working OK to provide power to your injectors and the hall sensor.

Of course this all depends on how you jumped the fuel pump. If you disconnected the tank plug and fed power and earth to the connector. Then everything else is ok. But you haven't eliminated the fuel tank earth (gearbox ground).
If you left the fuel tank plug connected and just fed power to the pump line then you have bypassed the fuel pump relay, you would however have eliminated the fuel tank ground.

 

[B4ndit]

How did you check that. Just because the fuel gauge is working, doesn't necessarily mean you have a good ground to the fuel tank. The fuel gauge is low current. A poor earth would only show up if you put a high current through it like a fuel pump.

I checked the earth on the tank connector at the end which goes to the relay. Good continuity form that to the frame. My logic regarding the earth from the pump to the earth is that because I can get it working from a direct feed and earth via the tank plug then that should be good. I might also be talking a load of bollox but I did these tests because the gearboc switch is on this circuit via earth.

 

[B4ndit]

What makes you think that! The bike runs better than ever when you jump to the fuel pump. That has to rule out everything. Apart from the fuel pump wiring. The fuel pump relay has got to be working OK to provide power to your injectors and the hall sensor.
.

Clutching at straws here. Hope your right as a new motronic unit is mega bucks.

 

[DrFarkoff]

Bandit If you have fed 12 v into the fuel pump and it ran well


Then it's the relay or the fuse! (says he hoping steppers isn't gonna Bitch Slap him like Gibbs does to Dinozzo! )

Fuses can look okay but are maybe a bit furred up? Best to swap for a clean new one to be sure and check the contacts where it fits

The relay you can just swap one across as Mike O says

Beep the horn (to make sure the relay is working) then swap it for the fuel pump relay if it was faulty it should start

 

[Ian J Hartley]

I agree with DrFarkoff with this, but what I don't understand is at post 60 you said you could get 12v at the fuel tank connector (green/white) briefly. Why then did the pump not run?

I think the way this works is when the motronic powers up, an earth signal is sent from the motronic to close the fuel pump relay. Fuel pump runs and primes the fuel line. After a second the motronic removes the earth from the fuel pump relay causing the relay to open and chop power to the fuel pump. When the engine turns the hall sensors tell motronic the engine is turning and it then reapplies the earth to the fuel pump relay. This powers the fuel pump and also as they are directly connected the injectors. Ergo fuel is delivered to the engine. This explains why when the motronic first powers up you should get 12v for about a second at the fuel pump tank connector and the injectors.

When you jumped 12v directly to the fuel pump tank connected, you bypassed the fuse and the fuel pump relay taking them out of circuit. You also bypassed the negative control signal from the motronic to the fuel pump relay.

I'm pretty sure this is something simple and obvious, but I can't see it.

 

[Comfy Old Boots]

Hey Bandit. Sounds like your having a right time of it. Don't know if this helps but on my r850, I have a situation where if I lift the tank and don't replace it and correctly rebolt it, my fuel pump will not prime. This had me confused for ages. I don't know why but unless I have all the washers attached where the tank attaches to the frame, the fuel pump will not prime. Indeed, when bolted up properly it is fine. I don't know how the current is flowing but I do know, if my tank isn't mounted properly the bike will not start. Initially, I thought it was a broken wire but wasn't.

Is there any chance you might have something like this? I probably haven't described it very well but your problem does sound similar. HTH!

 

[B4ndit]

Hey Bandit. Sounds like your having a right time of it. Don't know if this helps but on my r850, I have a situation where if I lift the tank and don't replace it and correctly rebolt it, my fuel pump will not prime. This had me confused for ages. I don't know why but unless I have all the washers attached where the tank attaches to the frame, the fuel pump will not prime. Indeed, when bolted up properly it is fine. I don't know how the current is flowing but I do know, if my tank isn't mounted properly the bike will not start. Initially, I thought it was a broken wire but wasn't.

Is there any chance you might have something like this? I probably haven't described it very well but your problem does sound similar. HTH!

Cheers mate. I know what your saying. I will do that later today. In fact I am going to concentrate on the ground side of things later today.

 

[(RIP) DitchWater]

I agree with DrFarkoff with this, but what I don't understand is at post 60 you said you could get 12v at the fuel tank connector (green/white) briefly. Why then did the pump not run?

I think the way this works is when the motronic powers up, an earth signal is sent from the motronic to close the fuel pump relay. Fuel pump runs and primes the fuel line. After a second the motronic removes the earth from the fuel pump relay causing the relay to open and chop power to the fuel pump. When the engine turns the hall sensors tell motronic the engine is turning and it then reapplies the earth to the fuel pump relay. This powers the fuel pump and also as they are directly connected the injectors. Ergo fuel is delivered to the engine. This explains why when the motronic first powers up you should get 12v for about a second at the fuel pump tank connector and the injectors.

When you jumped 12v directly to the fuel pump tank connected, you bypassed the fuse and the fuel pump relay taking them out of circuit. You also bypassed the negative control signal from the motronic to the fuel pump relay.

I'm pretty sure this is something simple and obvious, but I can't see it.

That is correct. The pin on the Motronic is said to "go low" when using electronics terminology.

Hey Bandit. Sounds like your having a right time of it. Don't know if this helps but on my r850, I have a situation where if I lift the tank and don't replace it and correctly rebolt it, my fuel pump will not prime. This had me confused for ages. I don't know why but unless I have all the washers attached where the tank attaches to the frame, the fuel pump will not prime. Indeed, when bolted up properly it is fine. I don't know how the current is flowing but I do know, if my tank isn't mounted properly the bike will not start. Initially, I thought it was a broken wire but wasn't.

Is there any chance you might have something like this? I probably haven't described it very well but your problem does sound similar. HTH!

My GSA will run perfectly well without refitting the tank completely and the Geezers should do so as well. His ground connection should be through the wiring.

We can't be far away from hearing some good news.