Allroad 2.5 2005, drop in economy, flat performance, longer cranking on cold start

[A. Waterfield]

FIXED : low pressure vein pump in the front of the fuel injection pump had started to fail, new pump body was fitted by Diesel Bob tuning, it requires a new pump ECU to calibrate to the new body. the total cost of the job £850+Vat (dec 2014 prices) excluding removing and refitting etc.

Having my 2005 allroad 2.5tdi V6 tiptronic for 2 months and 5,000 miles been perfect but now its all just not quite right. looked on the forums for various aspects but maybe you'll have a better idea than me. bought at 59k miles and now at 64k cam belt changed at 32K buy specialist.

It has seemed to be somewhat flatter accelerating than usual, mpg has dropped of by 2-3mpg (34.2 ave over 4500miles down to 31-32) and when cold it starting to take longer to fire. also i swear the oil temp is a little higher, usually reads just before 90deg now just over. maybe slightly noisier below 3k.

under the bonnet i noticed a small boost leak where front aluminum cross pipe enters left intake manifold. this has been stripped and re-sealed. no change.

also EGR valve has sooting around its top casing vents...

VNT movement looks fine. EGR Valve vacuum is present and when removed you hear the turbo spool a little and stops when re-applied, so seems to operate as i would expect?
no clogging in pipe work very clean really.

I have a basic plug in code reader/data display. no codes present (not vagcom i know) boost pressure static 105kpa highest reading approx 3k at 240kpa (18psi?)
timing at idle -2.5BTDC and highest read +3.0BTDC flat out over 3k. can the injector timing run out if the belts stretch a little? o

any pointers appreciated.

Many thanks in advance.
Alex

[A. Waterfield]

been out this morning, whilst not fully warmed up the performance is better than when warm. -0.5btdc at idle and +16btdc at full throttle 3k+.

[A. Waterfield]

More research suggests the egr soot marks are quiet common and not untoward. cant help but think the ECU is retarding the timing when warm.

[bluezie]

More research suggests the egr soot marks are quiet common and not untoward. cant help but think the ECU is retarding the timing when warm.

Every EGR I've seen on the V6 has a bit of soot on it, but not a problem.
Can your diagnostic kit read the measuring blocks, and do live data logging?
You need to check the fuel, coolant and intake air temperatures, throttle position sender, requested vs actual MAF, requested vs actual boost, torque limiters etc.. Also check operation of EGR in output tests, and observe change in MAF within correct limits, check operation of N75 / VNT mechanism.

[ametlib]

Looks like yours is acting up exactly like mine. Good luck and please post back if you find something

[A. Waterfield]

seems to be a common ailment, with many ive looked at in forums not finding the answer. we can assume it will be expensive. It is due to go to audi for service and trans oil swap this thursday, so may ask for a diagnostic printout, or bite the bullet and get Vag-com myself, as I do belive this is going to drag on and access to live data be paramount...

in my mind either ECU fault, or VP44 fault.

As the boost pressures go up in line with how it was prior to this issue i think the boost circuit/turbo can be discounted. it deffinately changes with the oil getting up to temperature. no noticable link to water temp.

As the car is so low mileage my mind does not believe VP44 pump failure can be an option?

ultimately untill I can get hard data, all my bable above is conjecture..

[ametlib]

I have changed both the ECU and the VP 44 ( and everything else for that sake ) I'll keep my fingers crossed for you not having the same fault as me, and the only help I can offer is really to wish you good luck ..

BTW I recognize the the longer cranking time when cold and also the higher oil temp, another strange sympthom is some plinky funny noises from the engines( cars ) right side at idle and only when the engine is hot

[A. Waterfield]

BTW I recognize the the longer cranking time when cold and also the higher oil temp, another strange sympthom is some plinky funny noises from the engines( cars ) right side at idle and only when the engine is hot

sounds very similar.

what parts have you replaced?

[ametlib]

2,5 tdi AKE running rough when warm. If you have some time to kill you'll find it here. If not the answer will be- everything you can possibly think of regarding this kind of fault, I.P, ECU, Camshafts+ rockers+pushers, all of the belts, rollers and tentioners, turbo,egr valve, MAF, Map sensor, Engine speed sensor, N75+ all of the small rubber pipes, Injectors, ASO ( just in case I forgot something )

Both heads been off and the best part- according to VCDS this engine is running like a dream ! Pick whatever graph you wish and actual is following requested like a shadow ??!!
So- as before, good luck

[A. Waterfield]

and today - its fine. mpg returning power returning started straight away....... hmmm for how long I wonder...