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Discussion Starter · #1 ·
Hi all, got this code today when I ran a scan, car was smelling of fuel. This code is fairly generic what's the best way of narrowing down the problem? With the engine off but with the ignition on there was a knocking noise which could have been the fuel pump.
Car is running fine, no misfires or stalling. It takes a tiny bit longer than normal to fire up. Car is on 49k miles.
Any thoughts, suggestions, ideas welcome.
 

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I'm not going to be of any help here, but I do think it strange that you just have that generic code. If there's a problem with that system, you might have also expected a "fuel rail pressure too high/low" dtc as well (P0087 or 88).
If there was a fault with the pressure sensor itself, that should also throw up its own codes - this sends out a 0.2v to 4.8v signal (corresponding to fuel rail pressure) and has a high/low voltage monitor to check it's ok.
I can't seem to find anything to explain which monitor generates P0089.
I believe the rail pressure is held constant, with a high pressure relief valve. If your scanner lets you look at sensor outputs in real time, have a look at the fuel rail pressure and see what it's operating at.
It might be worth having a look to see what the long term fuel trims are doing. If they're going well into the negative then it would indicate that the rail pressure is too high (and hence too much fuel being injected).
 

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Discussion Starter · #3 ·
I did think it was strange just to have that one code. I unlocked the door to get my glasses out this morning (took the wife's car today), and there was a knocking noise from the centre of the car for 5 or 6 seconds, then a fuel smell. Does the car prime the fuel system before you start the engine? I'm thinking there is a problem with the in tank unit, but why the smell? The smell is usually down to a faulty regulator and fuel getting into the lines isn't it?

Another thing could be a blockage perhaps, or crap fuel? Then again the car isn't stuttering. I'm struggling with this.
 

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A blockage would usually result in problems at high revs.
As I say, it would be helpful to have a look at the sensor outputs I suggested. A problem with fuel supply would give a low fuel rail pressure. If it's too high you'll be injecting too much fuel and your LTFTs will be trying to compensate (going negative).
There's a bit more diagnostic work you can do, but you need to look at real-time sensor outputs rather than just scanning for DTCs
 

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Discussion Starter · #6 ·
Getting a P0087 code now.
Ran some live data, the FPR at idle is 6,800 kpa or around 1,000 psi, goes up to 17,000 kpa when revved to around 4k rpm.
Is that high/low? I cannot find anything online to say what it should be.
 

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So P0087 is indicating fuel rail pressure too low.
The rail pressure sensor is outputting values in the range you would expect, so that sensor would appear to be ok. My data is a bit generic though, rather than specific to this engine.
The LTFT being negative indicates it's backing the fuelling off as it's a bit rich - which is strange when it's reporting rail pressure too low - you would expect the opposite. However, the LTFT needs to go to 25% before it raises a fault, so it looks to be ok where it is.
So this remains a bit of a conundrum. Could there be a fuel leak at the rail? - you said there was a smell of petrol?
 

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Discussion Starter · #10 ·
There appears to be a leak now, around the passenger front wheel which makes me think it's the hpfp. The feed pipe that has the push connection to the hpfp pipe had some movement in it, I could push it around half an inch. Do those connections fail?

Automotive fuel system Gas Engineering Auto part Electric blue
 

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There's a relief valve on the fuel rail and there's no DTC to suggest that the pressure has gone above this, so any failure here shouldn't have been caused by pressure above the normal range. A leak would potentially cause a rail pressure too low DTC though.
 

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Discussion Starter · #12 ·
Think I need to get in the passenger side, open the bonnet and strip the engine back to the hpfp and rail. Will then get someone to open the driver's door which usually starts the pump priming. I should be able to then spot the leak.
 
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