P0087 Code - Help !

[DarrenC95]

Hi everyone just looking for some help, I have recently fitted VIS HPFP Internal Kit to my MK5 GTI and since I have got the P0087 fault code, I have dissembled an reassembled the pump twice to make sure there were no mistakes an everything is perfect on that side

I also drilled the fitting to 5mm as advised by ovidiu at VIS, still no joy

I am doing a K04 Conversion at the minute an the other parts I have fitted are the below could any of these relate to the codes ?

S3 Injectors (With New Seal Kit)
Runner Flap Delete
RS4 Relief Valve

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[pudding]

Have you got the latest revision low side pressure sensor?  06E 906 051 K

Cam lobe for the HPFP OK and not worn down?  Cam follower OK?

If the above checks out, you will need to data log the following:

Fuel Pressure (LPFP) - Actual
Fuel Pressure - Requested
Fuel Rail (HPFP) - Actual
Fuel Rail - Requested
Fuel Rail - Difference
Lambda Control

LPFP should sit at 4.5 bar at idle and cruise, and ramp up to 5.5 - 6 bar at higher loads and/or rpm.

HPFP should sit at 50 bar at idle and cruise and ramp up to 109 bar at high load/rpm for stock tune, and 120-130 bar for remaps.

If the LPFP keeps up with demand, it's usually the HPFP.

See what the difference between actual and requested is and how hard lambda control is working to fill in the gaps.

That ought to give you some clues as to where the issue is.

How many data PIDs can that Snap on log at once?  Might be worth doing all the other suspects too, MAF, throttle, engine rpm, boost, timing retard, intake temp etc etc to give you a fuller picture.

[DarrenC95]

Thanks for getting back to me, a real headache haha

No the low pressure sensor has never been changed but there was no issue with it beforehand still could be an issue though

No unusual wear on cam and cam Follower was just recently replaced less that 1k kms ago

The issue is I cannot do logs with this Snap On diagnostics, as soon as I go to read measured block values it just says not available so will have to try source a VCDS

I might fit the old internals back into the HPFP to see how it goes

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[pudding]

OK no probs.  That is one cause of the error and there was a VW TSB about it some years ago.  That sensor is on it's 3rd revision!

Yeah that is the problem with a lot of generic scanners, they can't read live data on some German cars.  VCDS is definitely worth getting hold of for figuring out stuff like this.  We need to know if there actually is a fuelling shortfall, or if a sensor is lying.

[DarrenC95]

Can the new RS4 Relief Valve cause the low rail pressure fault?

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[DarrenC95]

I checked the measured block values and its showing the fuel rail pressure at idle is only at 9 Bar which is very low

Going to reinstall the old internals an see if it makes a difference

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[DarrenC95]

I put the old Internals back into the high pressure pump an same issue

 Low Rail Presure gonna order up a new G410 sensor on Monday to see if this will fix the issue

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[pudding]

The RS4 valve won't cause low pressure unless it's faulty and stuck open. Pretty much unheard of though!  Was it a genuine valve or an ebay special?

Hmmm, the engine would barely run on 9 bar, that's 41 bar shy of where it should be at idle.  Perhaps it is a sensor or the valve on top of the HPFP not governing the fuel pressure.  Is it cracked?  That's pretty common when folk are clumsy with the engine cover and press down on it.

Does your dip stick stink of petrol?  If it does, the seal in the HPFP might have torn when fitting the internals, and would explain some of the pressure loss.....but not 41 bar!

[DarrenC95]

The RS4 valve won't cause low pressure unless it's faulty and stuck open. Pretty much unheard of though!  Was it a genuine valve or an ebay special?

Hmmm, the engine would barely run on 9 bar, that's 41 bar shy of where it should be at idle.  Perhaps it is a sensor or the valve on top of the HPFP not governing the fuel pressure.  Is it cracked?  That's pretty common when folk are clumsy with the engine cover and press down on it.

Does your dip stick stink of petrol?  If it does, the seal in the HPFP might have torn when fitting the internals, and would explain some of the pressure loss.....but not 41 bar!

No I bought the RS4 Valve Brand New From Main Dealer Audi I doubt it is faulty but can't rule it out either I hope it's not

I think its the low pressure sensor on the side of the HPFP as there has been a couple of revisions an my one is the older version

No I have checked the oil also to see if the petrol was mixing an thats not the case either, I have ordered the low pressure sensor an should have it tomorrow so will fit it an see if It sorts the issue

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[DarrenC95]

See below, 9 Bar Fuel Rail Pressure showing at idle

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[DarrenC95]

SOLVED

Had to replace the HPFP with a new Genuine Pump, also changed the fuel filter while I was at it

Now the problem is I'll have to remove the new pump now to swap the VIS Internals into it hopefully it goes OK

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