Timing and tdc

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May 16, 2022 | 06:51 PM

AudiJayq7

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Timing and tdc

I am replacing my hpfp on my 2010 q7 3.0 tdi due to catastrophic failure. Repair instructions say to set engine at tdc so i figured before i take hpfp belt off i would set crank at tdc and then remove and reinstall components but when i turned the crank the cam sprocket did not turn with crank ( all belts are still inplace). Is the cam independent? And if no belts have been removed as of yet with turning the crank did it affect the cam position? Thanks

May 17, 2022 | 04:23 AM

testarossaguy

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From: Alabama (formerly Michigan)

About how many degrees of rotation did you apply to the crankshaft? Did you rotate the crank in the correct direction (same as when the engine is running)..? Prior to the HPFP failure, did you have any timing chain rattles at cold-start-up?

May 17, 2022 | 04:55 AM

AudiJayq7

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I turned the crankshift/ harmonic balancer maybe 3/4 of a full revolution to get the tdc mark to 12oclock. As stated no belts have been removed as of yet. But the sprocket that drives the hpfp did not move. Does turning the crank by hand affect the cam sprocket that drives the belt for the hpfp or is it computer driven?

May 17, 2022 | 04:57 AM

AudiJayq7

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Crank has been turned clock wise only and there has never been a rattle or mysterious noises from the engine.

May 17, 2022 | 09:35 AM

testarossaguy

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From: Alabama (formerly Michigan)

Clockwise as when your facing the engine - looking towards the rear of the vehicle....right? It seems like the toothed belt that drives the HPFP is driven off of the driver's side Intake Camshaft...right? If so then yes....when you turn the crankshaft the camshaft should also turn. How did you determine that your HPFP had failed? Metallic particles in the fuel system?

Last edited by testarossaguy; May 17, 2022 at 09:55 AM.

May 17, 2022 | 01:31 PM

AudiJayq7

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Yes drivers side. It died while driving, took it to audi dealer said catastrophic failure of the pump told me $17000.00 to fix which wasnt an option. Had it towed home and ive been pulling parts off cleaning them in my ultrasonic cleaner. Ive pulled injectors disassembled them cleaned and reinstalled with new copper washers and seals torqued to spec now im at the pump removal and reinstall. The vw dealer that services my q7 said the front sprocket that drives the hpfp is independently driven and printed me off the repair/service walkthrough how to do the cam timing. Slow process but ive got a used pump and any new parts ordered so im set until i get to bleeding the fuel system then im buying vcds and get a laptop doingvthe pre start up myself. I plan on doing this entire repair all expenses around $2000 or less.

May 18, 2022 | 04:08 AM

testarossaguy

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From: Alabama (formerly Michigan)

Wow that's a major DYI job for sure! So it's as you suspected earlier - that the HPFP computer controlled and / or driven? From reading through other threads about HPFP failures, it sounds like metallic particles can contaminate the entire fuel system (tank, injectors, lines, etc.).which is why it's such an expensive repair as Audi just replaces everything. Is your fuel pump the CP3 version or the CP4? You will find that Vag-Com is about the best money you can spend and it will pay for itself many times over - it is an absolute necessity for those of us who actually turn wrenches on these vehicles.