easiest way to change fuel pressure regulator

gothbiker

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Which is the easiest way to change the above, tried search and can't find anything (using mobile phone) pita
Thanks Dave
 
Manual says.....

FPR.jpg


The ref to See Group 23 refers to sealing fuel lines when disconnecting them

• Remove the seat.
• Remove side panel.
• Disengage fuel tank.
e Caution:
Fuel is flammable and a hazard to health. Observe
relevant safety regulations.
• Seal the fuel feed and return lines with hose
clips, BMW No. 13 3 010, and disconnect.
• Disconnect breather lines.
• Disconnect plug of fuel pump unit.
• Remove fuel tank.
• Remove the battery.
 
Which is the easiest way to change the above, tried search and can't find anything (using mobile phone) pita
Thanks Dave

Please tell: What are the symptoms to make you think it needs replacing?

I have a bit of a fuelling issue and was wondering whether it was those parts as well. :confused:
 
No problems as such, just have a 3.5 bar to fit, will have the original one if your interested?

I haven't looked it up yet but at what pressure does the standard one run and are you upgrading (if that's what it is) for an engine tune or something?

And yes, I may be interested in your original unit but, if you find it a good home beforehand then let it go.

My fuelling is irregular when the bike is warm and I'm stopping, doing something (bacon butty break), and starting again. Then on restart the engine feels like it is missing fuel until I give it more twist grip.

AFAIK the fuel pressure reg' is mechanical (I will study this) and I don't see how it could be so severely affected by temperature. :confused:
 
It can be done without removing the rear subframe, but it's very very fiddly, and i do mean very very.

It helps undoing and removing the three screws that hold the airbox in place so you can move it back a bit.
 
I haven't looked it up yet but at what pressure does the standard one run and are you upgrading (if that's what it is) for an engine tune or something?

And yes, I may be interested in your original unit but, if you find it a good home beforehand then let it go.

My fuelling is irregular when the bike is warm and I'm stopping, doing something (bacon butty break), and starting again. Then on restart the engine feels like it is missing fuel until I give it more twist grip.

AFAIK the fuel pressure reg' is mechanical (I will study this) and I don't see how it could be so severely affected by temperature. :confused:

That sounds very similar to a problem I had on my car - the hall sensor would get hot when you stopped for a break because it wasn't being cooled by the airflow that you get when driving. Because it was on the way out, that was enough to push it over the edge and the car would just refuse to start until you had left it about 30 minutes.
 
Doh....

FPR.jpg


The ref to See Group 23 refers to sealing fuel lines when disconnecting them

• Remove the seat.
• Remove side panel.
• Disengage fuel tank.
e Caution:
Fuel is flammable and a hazard to health. Observe
relevant safety regulations.
• Seal the fuel feed and return lines with hose
clips, BMW No. 13 3 010, and disconnect.
• Disconnect breather lines.
• Disconnect plug of fuel pump unit.
• Remove fuel tank.
• Remove the battery.

I must have misread the manual, had the impression you could do it just be removing the airfilter box.....oh well live and learn....:D
 
I must have misread the manual, had the impression you could do it just be removing the airfilter box.....oh well live and learn....:D


No, you're right. It can be removed just by removing the airfilter box.

But do you know what's involved removing the airfilter box :D
 
That sounds very similar to a problem I had on my car - the hall sensor would get hot when you stopped for a break because it wasn't being cooled by the airflow that you get when driving. Because it was on the way out, that was enough to push it over the edge and the car would just refuse to start until you had left it about 30 minutes.

I changed my Hall sensors but that didn't help very much. It appeared to do so at first :confused: but the problem is now more apparent and it's getting on my nerves now. I had to take on a gravel track last night, and a long one with a load of that pea stone (jusk like chunky sand) and was diverted back along the track to my special parking bay. So I start-up again and the bike is dying on me so I'm gassing it and it's just so difficult to control. The hotellier will not be happy if he finds out I was roosting his driveway.

Someone told me to have my throttle bodies rebuilt so that may be next.
 
I changed my Hall sensors but that didn't help very much. It appeared to do so at first :confused: but the problem is now more apparent and it's getting on my nerves now. I had to take on a gravel track last night, and a long one with a load of that pea stone (jusk like chunky sand) and was diverted back along the track to my special parking bay. So I start-up again and the bike is dying on me so I'm gassing it and it's just so difficult to control. The hotellier will not be happy if he finds out I was roosting his driveway.

Someone told me to have my throttle bodies rebuilt so that may be next.

My brother in law had a similar problem and it was a tempreture sensor, starting the bike when hot was a reall pain and somtimes just would not start at all untill completely cold.
Might be worth a look
 
Thanks for that. :beerjug:

I'm struggling to accept that it could be the air temperature sensor in the air box because it's probably not that hot in there so, will have to have a look for an oil temp' sensor.
 
I'm struggling to accept that it could be the air temperature sensor in the air box because it's probably not that hot in there so, will have to have a look for an oil temp' sensor.


That's the point - It might not be that hot in there, but the switch could be telling the engine that it is very very hot, or very very cold.
 
Air Temperature Sensor.

That's the point - It might not be that hot in there, but the switch could be telling the engine that it is very very hot, or very very cold.

Okay.

After finding this yesterday afternoon upon my return from the Cotswolds, and the bike had cooled down sufficiently, I measured the resistance of my air temp' sensor and found just under 2K ohms across its terminals. I'm going to take that measurement again soon as a genuinely cold measurement, and then I'm going to carry my multimeter with me and do the same and see if I can determine whether that component is problematic.

For those interested: As far as I can tell so far the air temp sensor will be a Negative Temperature Coefficient (NTC) resistor, and is more commonly referred to as a thermistor, whose resistance falls as the temperature goes up. (There are also Positive Temperature Coefficient resistors, which function with the opposite characteristics and I know these from there use in power supplies and other electronic damping systems.)

Note: My 2K ohms measurement above would appear to indicate a very high ambient air temperature, as found in this table:

ait-testing-chart.gif


The above table has been lifted from a motorcar mending website and I don't know how pertinent it will be to a GS sensor but I'm using it at the moment as a guideline.

So, last night my sensor thought it was measuring around 100C in a garage on the north facing side of the house. :confused: I think I would have noticed that :augie but, what it means is that the Motronic thinks it needs to reduce the fuel supply to match the low air density of a high temperature atmosphere and consequently provide the engine with the correct air/fuel ratio.

Anyway, I'm going to pursue this further by trying to find out the electrical characteristics of the GS sensor (I want a factory manual :blast) and I'll let you know what I find.
 
Right then. Bike in garage all night and completely cold. Ambient temp' around here today is about 20C for shorts and T-Shirt.

Air temp' sensor measures 2.7K ohm, and using the above table it's 90C which I don't believe. It could a PTC though?

More later when I've changed my wheels and been for a ride to the off license. :beer:
 
More later when I've changed my wheels and been for a ride to the off license. :beer:

No need to ride the bike - Take the lid indoors and use a hairdryer/hot air gun on the temp sensor and read your meter as you do it. .
 
No need to ride the bike - Take the lid indoors and use a hairdryer/hot air gun on the temp sensor and read your meter as you do it. .

Hairdryer!:eek: Have you seen the top of my head?

I do agree there are static tests to be done to clarify the operation of the air temp sensor but wanted to carry out the dynamic test as well because this is where I experience the problem.

So todayI ride the bike for 40 min's, get five bars on the oil temp' display, arrive at :tesco and measure the resistance to be 2K ohms again at about 19C ambient, because it's clouded over a bit.

Then, after 25 min's shopping, find the resistance to be around 1.7K ohms with three bars on the RID.

Go home and measure the sensors resistance again and find 2.13K ohms, after a 30 minute ride with five bars on the RID.

I wait ten min's and measure again and get 2K ohms with four bars on the RID and abient temp' still around 18C or 19C because it's a bit windy now.

Thus far I can see that these values are somewhat limited in range but will do the hairdryer test.
 


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