Possible Fuel Pressure issue - help diagnose please!

Had my 2.0T a year (4 year old 197bhp BWE engine, 50k miles) and it has generally been running ok but with niggles. I get the feeling its a car that wasn't properly looked after before - more a case of someone not checking under the hood often, checking oil etc rather than thrashed.

So, the last bit of an extended warranty I've had a rear oil seal and sump leak needed repairing, PCV and rocker gasket all changed, done the PCV breather myself, it's had a major service, cam belt, gear oil, brake fluid, air con refresh. So getting there!

The car hasn't kicked out any actual error codes on the engine until this weekend when it came up with a P0087. This wasn't there midweek and I did have a cambelt change done in between this. Would a cam belt change kick out this code? I cleared it and on a 30 min drive it didn't reappear.

I am wondering if I do have some kind of wider issue, as one log that I've never been too happy with is the lambda. On VCDS, my idle long term value is between 0-1%, but my throttle long term value tends to settle at 13.7%, which is slightly out of spec, but not enough to trigger a CEL or other VCDS error code.

Having received the P0087, I'm wondering if these are linked. My understanding is that the cause of P0087 can be fuel filter or camshaft/follower etc. My understanding of the long term fuel trim out of spec is that this is typically be a clogged injector/fuel issue or faulty MAF.

I've logged my MAF under WOT and got 156g/s which seems pretty spot on for my engine (repeated it several times). Also gave the MAF a clean just to be sure.

I've also logged actual vs requested boost and that seemed alright - basically it was slightly behind initially, but by 2500 revs it was bang on and then followed request well. [someone correct me if this isn't ok!]

Now I haven't checked the follower - it's next on my to do list (and check the HPFP for wear), but as the rocker gasket was changed recently, the mechanic told me that the camshaft looked in good condition. Also I logged rail pressure actual vs request a month ago and it was really spot on. I'm hoping that this means that I should be ok on the HPFP front pending that visual inspection and cam follower change.

So, over to the fuel pump. What can you do to check this? I logged VCDS block 106 whilst the engine was on idle and the lift pump duty cycle sat at around 56% which is in the 'grey area' according to VCDS.

I don't know if this is related, but also if I fill up my tank, my fuel gauge sometimes doesn't actually read maximum - not sure if this is a fuel sender issue.

So my questions are:
- would you guess these are connected issues (high lambda on 32, VCDS 106 and/or P0087)
- what other potential issues could be causing some of these problems?
- what checks could be easily done to try and rule out any other parts?
- does the above testing sound reasonable for pointing at a fuel pump issue?
- if so, would the next thing (after doing a HPFP check & follower replace) be to change the fuel pump?

Thanks for any help in advance.

NHN said:

Follower is imperative, the ramifications if its worn or even with a hole are expensive, trust me, I worked on a car that had the cam reshaped, bucket with a hole in & the nipple on the end of the fuel pump worn to a silly angle.

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Yep, it's next on my list to do - hopefully be able to address it in a couple of weekends time.

So to follow up on this thread. I went for a driver around a week ago, gave the car a couple of blasts and the code came back. Also twice whilst driving the car just didn't boost - but then was fine 30 seconds later. Overall I do feel like I've lost a bit of power so I'm going to need to boost test it (I have a rev D DV, so hoping that is fine).

Finally checked my cam follower today and there was some wear, but not too bad I thought - I'll upload pics a bit later for some expert opinion. Thanks NHN for forcing me to do it sooner rather than later though - it's given me peace of mind to know its not about to blow!

Pics below - obviously some wear, but nothing like the catastrophic ones I've seen elsewhere.

Overall, does the below look ok?

Giosabcsl said:

That wear is perfect considering it didn't wear through.

What year model is your vehicle?

So you can scratch the cam shaft issue off.

As for the fueling issue. I would say make sure you are running premium fuel as well as check when last the fuel filter was changed as this can also cause the issue they recommend the fuel filter be done every 15000 miles.

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This is where I fess up, I don't have an audi but a Seat Exeo, b7 platform and late b7 engine, in effect, so I am a gate crasher here but the knowledge here is to good not to be a part of. Car is coming up to be 5 years old.

I always use premium, shell out tesco, doubt previous owners would have though.

I doubt the fuel filter has ever been changed to be honest. Next on my list then! Looks easy to do and have to say happy with myself as that cam check and change is probably the hardest diy I've done!

Craig Cull said:

*lobe

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It's that measuring the cam lobe under the rocker cover our the cam follower piston?

Actually drove 150 miles at the weekend and no sign of the error code again. If only small differences throw it off, then maybe the can wear had just got to a point where it was triggering the code?

Think will do the fuel filter at some pointlater this year , but otherwise spend my efforts on checking for boost leak and finding the source of my high value throttle value on block 32.

Cheers. Think I'll try a few other things first if the code reappears.

Quick side question - the car has only had vpower/tesco 99 in it for the last year (but who knows what before that for several years). Do you think the fuel injectors would benefit from some kind of fuel additive, or is the stuff that is normally in those two petrol types doing the same stuff?

Craig Cull said:

To be honest mate, with it being direct port injection the additives don't really do anything as all it does it fire it straight into the combustion chamber. Your running it on the best fuel for it really, all you could possibly do is add an octane booster but all your really gonna do is help it run a little cooler.

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I thought the injector heads could still get a bit clogged?