Fuel starvation is my knee-jerk response. Is it possible that you kinked a fuel line when you fit the tank back on?

 

Thanks jeffyjeff, I shall look for kinked fuel line tomorrow and let you know …

 

Well I did look and there are no kinks.. I disconnected almost all of the connections, cleaned and reassembled but still have the problem.

does anyone have an electrical wiring diagram?
It starts fine and the revs start to rise when the throttle is twisted but just doesn’t go above 3,500 rpm..

Very frustrating…

 

In that case I would check the TPS (Throttle Position Sensor) calibration. It is possible for a mis-calibrated TPS to send a wonky signal to the ECM (Electronic Control Module) even when the throttle control is rotating completely through its arc. It is also (remotely) possible that you unintentionally disturbed TPS calibration during your service work. You will need an OBD2 diagnostic scan tool to check the TPS. Many on this forum use the MotoScan App with an OBDLink adapter. I use this combination and it works well. Probably better to unobtrusively and electronically probe the ECM before disturbing the electrical wiring and connectors.

 

Hi Jeffyjeff, thank you for your reply.

I have a couple of questions, please excuse my ignorance but I grew up with bikes that only had; points, condensors, regulators and that's about it! No fly by wire or computers in those days! 🤣

wrt my symptoms.. throttle twist working and revs rising - but only to 3,500 rpm, would the TPS being mis-calibrated cause this? How is it calibrated, is it an electrical or mechanical thing and how could I have disturbed it? Will the diagnostic scan tool be able to recalibrate it?

I have never used an OBD2 diagnostic scan tool or the MotoScan App with link adapter, what will this give me/ tell me? What does it do? Is it a good investment? is it expensive?

I shall look for other threads on OBD2/ Motoscan..

Thanks,
Jon

 

I would be grateful for any suggestions, thank you.

Just a thought....
Are you 110% sure that the sparkplug is the correct type/model ?
And " I reconnected fuel line, breathers (top and bottom) coil and electrical connector.." - what "electrical connector" ?

 

Thanks, enclosed copy of the new spark plug box that I fitted and the spec in the Rider’s Manual, so am 110% sure. The electrical connector at the bottom of the tank, has 4 wires and a clip.. 👍

 

Maybe, and it is just a maybe, you have poor fuel. If you have fresh petrol and a full tank this is unlikely but if the bike has stood all winter with a bit of E10 doing its horrible degrading best....

 

Thanks, full tank not that long ago.. but heh, you never know… will consider that suggestion 👍

 

I leave my G310R servicing to BMW. I can service my 70 year old Velo, but this new stuff is beyond me. Hence fuel suggestion. Other is pug gap - my chainsaws are fussy in the regard - and may be a blocked breather. Does the bike improve if you fire it up with the fuel cap open.

 

Thanks, I did try the cap but to no avail.. 👍

 

Probably the connector for the fuel pump.

 

I shall take a class set look, thanks…

 

Maybe there was some debris in the bottom of your fuel tank. You could try and shake it around a bit before tearing everything apart. Sounds like a restricted fuel issue if it's not setting a light on the dash. Fuel pump connector either works or it doesn't, a loose wire isn't going to run the pump at half speed or something. Pinched line would significantly reduce fuel flow and it'd probably be stalling out or intermittent. Bad spark plug gap should set off an engine code and warning triangle. Clogged fuel screen will often stay clogged until you clean it out. Slim chance it's a vacuum issue, you can usually rule that out by running it with the fuel cap open.

 

Thank you, I shall look at this further.. I did contact a BMW specialist and he said the fuel position sensor sounds likely as he replaces about one a month. I have bought a second hand one off eBay so we shall see.. I will post if it solves the issue 👍

 

So, I tried the replacement that I bought on eBay. Still have the same issue. Resolution to this problem continues.. possible fuel filter replacement? Will try shaking the fuel tank to see if any improvement... Thanks for all of the suggestions and comments though.

 

When you changed the air filter, did you replace it with the same type? I once fitted one to a bike the wrong way around and choked the throttle response. Might be worth a check to see if it's seated properly. Just a thought, although I may well be talking twaddle ..again...

 

Thanks, I’m pretty sure that I fitted it ok, but I shall look.. it has a lip around it..

 

See? Told you l was talking twaddle...again..😂

 

good twaddle - all twaddle is good until it be prove not to be - its worth looking at all avenues.. thanks

 

Good day Jeff ,the throttle no rev past 3700 is exactly the same problem as this 310r here with only 600km on it, the bike has been sitting for year or more and started every few months but this time no rpm past idle. Drained old fuel ,fresh fuel no change, idles sweet as so I'm ruling out the injector being clogged just hoping the problem not the EMU The bike belongs to my boy that is working away So if the bike has to BMWsevice shop it is a 7 hour round trip. I will post any developments

 

I took the bike to an independent bmw specialist, he connected the bike up to a computer. All the indications are that it is a throttle position sensor - as it shows 12.5% only…, he is going to price one up and also check if there have been any recalls on this part, I shall let you know..

 

Tkd-jon thanks for the reply throttle sensor yes that makes sense I was thinking everything mechanical should be ok these sensors can pop any time just like spark plugs Rang the boy this morning and told him to save some money l live between Townsville and Cairns,far north Queensland Australia thanks for the reply Cheers Shane

 

Hello, did you ever get this issue fixed? I’m having the very same issue on my bike, and I can’t even find a part number for the throttle position sensor. Any help would be appreciated!
thanks
glen

 

Hi,
sorry to hear about your issue - this has been taking me an age to sort out.. the bike should be going in to the bike shop today!! to have a new throttle position sensor fitted but just rung them and they are still waiting for the part to arrive from BMW. If this is successful I shall send you all of the details..
nb the sensor is imbedded in the throttle assembly..

atb,

Jon

 

The genuine replacement part, as below, worked. I do have a warning simbol on my dash though..

 

You can teach the new sensor values between 0-100% throttle position with the Motoscan app. The warning light should disappear after this. BMW can also do this of course.

I guess your bike should run fine in general, but the TPS values may be wrong if the light came one by itself. It could be that your ECU registers a negative throttle position on idle for example giving you more „free play“ at idle or it may prevent you from reaching a throttle position of 100%.

 

tkd_Jon,
Thanks for this! I have one ordered. Hopefully it works as well.
I also figured out that the TPS sensor on the other end is actually integrated into the throttle body, not a separate part. So if that sensor is bad, you have to replace the whole throttle body. Here’s hoping it’s just the throttle grip!
g

 

tkd_Jon,
Thanks for this! I have one ordered. Hopefully it works as well.
I also figured out that the TPS sensor on the other end is actually integrated into the throttle body, not a separate part. So if that sensor is bad, you have to replace the whole throttle body. Here’s hoping it’s just the throttle grip!
g

Good luck g...

tkd_Jon,
Thanks for this! I have one ordered. Hopefully it works as well.
I also figured out that the TPS sensor on the other end is actually integrated into the throttle body, not a separate part. So if that sensor is bad, you have to replace the whole throttle body. Here’s hoping it’s just the throttle grip!
g

🤞🤞🤞

 

Good luck g...


🤞🤞🤞

did it work?

thanks, Jon