Came across a XB throttle body lately, that had a sensor mounted, just above the front injector's fuel rail. I have not seen this before, so I guess it's a 2010 model throttle body. Do they come with a fuel pressure sensor? Does the fuel pump still have a fuel pressure regulator installed, or is pressure controled by the ECM now, like the 1125 models?

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett

Yep, 2010 models have them (#15). Not sure how the pressure is controlled though, I would guess the fuel pump is not powered when pressure reaches x bar...

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08 Specialized Langster

Thanks a lot. Do you have a wiring schema to verify the sensor is connected at all?

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett

Grey 10

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08 Specialized Langster

The electrical diagnostic book says it is there to correct the injector duration. Lots of ECM (BUE2D) config data.

Shouldn't take long to put a cohesive story together, perhaps using a 2010 XB ECM for data...

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08 Specialized Langster

Great. Thanks a lot.
Same pin as used for 1125, so I guess, the setup will also be similar to these.

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett

You guys are awsome! Where do you learn all this stuff?
I'm still in the land of carburettors

You big tease, you know this stuff inside out...

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08 Specialized Langster

I think, we have a story already, as Nigel was struggling against (dropping) fuel pressure, which he cured with a better pump. This was all clearly visible in the logs. Very impressive to watch, how one issue triggers the next.

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett

Lets be hearing it then young man...

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08 Specialized Langster

I borrowed a pump off little Joe,unfortunately it was completely shot and struggled to make required pressure. To combat the low pressure the ecm increased injector pulsewidths - a lot- in some cases to unfeasable duration.

I tried a large walbro which really improved pressure stability,reducing the large drop on going wot,to almost nothing and cyt fluctuation on a run to 1 or 2 psi,where they had been upto 10psi,or all of the wot increase that the ecm had demanded. The walbro also ran at much lower duty cycle.

However the walbro didn't appear to like being pw modulated and occassionally made strange noises,so I now use an HCR 290lpm,flows less than the walbro but has been trouble free for the last 4months or so.

I'll see if I can find some logs.

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Nige...1125d 9.43@140mph

Honi soit qui mal y pense

Before:


After:


Fuel pressure (red) and fuel pressure setpoint (white) are shown in the bottommost pane. As you can see in the second image, the algorithm works quite well.

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett