D5254T (to 2002, Audi) Pump timing question

[BillQQ]

Afternoon

I've now read many pump timing threads, but still have a question as I've finally got Vida working on my '01 V70 TDI and I thought I'd give it a go. It sounded like a good thing to try as it was reading -3 degrees(ish) when I started the timing test routine in Vida and I think that there is room for improvement on my fuel economy and smoke emissions.

I was expecting to be able to tweak the tension up and down via the allen key, and see the timing move one way or another. However, it is proving to be more mysterious in its behavior and my adjustments (either direction) don't seem to be bringing it closer to 0deg +/-0.5 deg.

In all cases, I've been basing the values on the reading you get in Vida when you press 'Start' on the timing test, rather than the value at idle, which can be significantly different and bounce around.

After multiple tweaks up and down, it is settling out to be approx -3 deg again under test conditions, but the tapping at the pump sounds a fair bit noisier now. I'm also finding that the timing reading varies considerably when using the accelerator pedal to set different engine speeds - At one point it jumped to +4 deg when I increased the engine speed to ~2,000 rpm.

So, I have a few Noddy questions:

1. Should you always adjust the timing based against the test condition in Vida (slightly raised idle speed)?
2. Would you expect the timing to be different at other RPM?
3. What defines the limits of the tensioner adjustment and how much is it expected to rotate?
4. How noisy would you expect it to be, and should it sound better when well adjusted? It sounds like much of the noise is coming form the oscillating stops on the adjuster and changing the pulley tension is giving more or less clearance for it to rattle.

It started getting dark this afternoon so I'll have another go tomorrow. I'm thinking of loosening the tensioner bolt and then get someone to start the engine whilst I tinker with the allen key and see how it affects it without all of the starts and stops.

Other things to note:
- I've been starting and stopping the engine to reduce the likelihood of mishaps.
- The air pipe that runs past the timing belt has been disconnected, to allow adjustments to be made

For those who made it to the end of this post then thanks, especially if you also have the energy to reply!!

Best regards,

Bill

[BillQQ]

Okay, so I've just looked more carefully at the information in Vida and I think that my issues are that I was adjusting the upper belt tensioner rather than the lower idler, and was wondering why it didn't seem to affect the timing much. Obviously rushing too much with fading light and going backwards and forwards to see the laptop screen rather than having it on-hand to double-check everything - What a donkey!

I've just popped outside and re-tensioned this so that the arrows line-up and will see how that sounds tomorrow.

Is it advisable to relieve some of the tension before adjusting the idler for the timing??

I'll report back tomorrow and hopefully this post will help others not make the same mistake.

Bill

[Martin Cox]

I'll try and answer some of your queries but my experience is based on a 1998 V70 Tdi with the earlier MSA15.7 engine management which will not work with VIDA rather than your MSA15.8 setup. However it is mechanically almost identical.

The amount of adjustment available by moving the tensionser and idler on the injection pump belt is quite limited; about +/- 2 degrees. If the timing is out by any more than that, you need to adjust it by moving the camshaft pulley (the one driving the injection pump belt) relative to the camshaft. The aim is to get it within the range that can then be fine-tuned by tweaking the idler and tensioner.

I do it by setting the the idler and tensioner to their mid-positions (maintaining correct tension on the belt, of course) and adjusting the camshaft pulley to bring it within 2 degrees of the correct figure then fine tuning with the belt adjustments.

Yes, set the timing based on the test condition defined in VIDA. It's the only set of conditions at which the timing is accurately defined. I would expct that the timing would be different at different RPM. I'd expect the timing to advance with an increase in RPM.

With regard to point 4, it ought to sound better when the adjustment is correct. If the pointer on the tensioner is bouncing around excessively, something isn't right.

However the vacuum pump for the brake servo, which is driven fron the camshaft, is a notorious source of clattery noise on these engines. If the noise disappears when the brake pedal is pressed only to return a short while after releasing the pedal, then it's the vacuum pump.

Starting and stopping the engine is fine and is the sensible and safe way to do the adjustment. Messing around with the tensioner and idler whilst the engine is running seemed altogether too fraught with a one way ticket to disaster all too easily bookable.

Realistically you have to disconnect the air pipe in order to get at the injection pump belt. Being disconnected does not cause a timing issue and you can confim this by checking the timing with VIDA after reconnecting the pipe. It shouldn't be any different. It isn't on mine.

Rudi Dudi claims to be able to tell when these engines are timed correctly just by listening to them. I can well believe him but as a mere tyro I have to resort to the software to tell me what's going on. My ears aren't that good!

Hope this is of some help

Martin

1998 V70 Tdi

[Martin Cox]

In effect you alter the timing by moving the idler and then adjust the tensioner to keep the tension correct.

The belt path length between the camshaft pulley and the injection pump has to be tightly defined or the timing will be unstable. Hence somewhat confusingly the idler is on the tension side of the belt. The tensioner takes up any slack by being spring loaded and free to move but needs to be adjusted in sympathy with the idler to keep it within its correct operating range.

Hope this is of some help.

Martin

[Baffler]

In addition to Martin's excellent advice you may also wish to check/inspect the the type of tensioner and idler used. INA or Litens are the OEM components and I've seen some rubbish tensioners, that came within the Gates belt kits, which don't sit correct/flush and go askew causing a whole host of issues. The belts are perfectly fine...it's just the outsourced tensioners/idlers to be aware of.

It sounds as though you're working with an old belt so it'll have stretched some by now, leaving very little adjustment on the tensioner/idler, and probably adding to the wild fluctuations you're seeing. Any idea how old it is? Might do no harm to consider and fit an new pump belt altogether.

And how is everything looking at the other end, the cam belt side, all running true and tensioned correctly?

[BillQQ]

Sorry for the late reply - I fixed this a couple of weeks ago and was meaning to send this message, but only got part-way through it before being distracted.

Thanks Martin for your help - It's all done now and sounding much better.

As a wrap-up, here are the steps that I followed - Hopefully they are useful to anyone doing the same, though there are also plenty of other good threads that discuss it (I'll add a few links at the bottom).

*** If anyone spots anything wrong here, please correct so that I'm not spreading disinformation. If you are looking for information, scroll down and check for updates! ***

Software & hardware
- I'm using Vida via a Mongoose lead instead of Dice. This works for my '01 V70 TDI with the MSA15.8 engine management computer. I followed the instructions on Volvodiag.com, including downloading their virtual machine for use in Virtualbox - All of this is explained @ Volvodiag
- I gather that VolFCR works for the earlier MSA15.7 set-up.

Removing covers etc
- To be able to make the adjustment, you need to do the following:
- Remove the fresh air pipe that ducts air from the top of the front grille into the airbox (takes a little wriggling to get it off)
- Remove the padded cover that fits over the oil dipstick and sits between the fuel pump and the radiator (if you still have this part installed). When you take it off, watch out for the washers falling out and getting lost into the engine bay
- Remove the flexible air duct to the right of the pump belt cover on the right of the engine. I struggled to get it comp0letely off so instead just disconnected it at the top and tied it back so that it was out of the way
- Remove the pump belt cover, which is held on by two long bolts into the engine (13mm socket). On mine, the front bolt had a locking nut on it too, which should be removed first.

Vida
Then you need to get Vida fired up, and go into:
- Diagnostics menu
- Vehicle Communication sub-menu
- Click on the ECM module
- 'Advanced' tab
- Click on 'Check and adjust dynamic pump setting'

The coolant temperature needs to reach 80C and the fuel temp needs to reach 30C for this to work, so you may need to run the engine for a little while. This will also stop the battery from going flat when the diagnostics are connected.

To start the test, click on the drawing of the box, just above and the right of the graph. This will bring up a window showing the engine temp, fuel temp and current timing - The latter two will not be available until the engine reaches 80C.
Press 'start' and the engine will change to a fast idle - This is the only condition at which the timing should be taken.

The graph shows the acceptable timing, for a given fuel temperature.

Adjusting the timing
- To make the adjustment, first turn off the engine (if you value your fingers!)
- Ignore the tensioner, and look a little lower and further back into the bay to the idler pulley. Both have a bolt and Allen key socket, but the idler needs a 16mm socket rather than a 13mm one.
- Put an Allen key into the hole and then use a 16mm socket to loosen the bolt.
- When it has been loosened slightly, you can use the Allen key to rotate the idler, which slightly changes the path length between the driving sprocket and the pump gear. It doesn't move far, and has limited adjustment capability.
- Try moving it a little (I think that clockwise rotation of the Allen moves the timing in a positive direction).
- Retighten the idler with the 16mm socket (25Nm)
- Start the engine and re-start the timing test in Vida
- Check the value and repeat as necessary

Note that there is a limit to the adjustment. If you need more then there are quite a few posts here talking about how to deal with this, but I'll not go into it as I don't have any experience of this.

By the time I had finished, my fuel temperature was about 35 degrees and the timing was hovering around +0.0 to +0.2. You may want to search around to see if there is a better optimum value to aim for.

This is a good point to check the tension of the belt, while the engine is cold. The tensioner next to the fuel pump and has a pointer on it, which should be lined up with a marker. This pointer tends to move a little when the engine is running so it's not an exact science, but be careful not to adjust it so that it is too tight. The adjustment is done in the same was as the idler - By loosening the central bolt and then using an Allen key to rotate the tensioner on a cam, before tightening the bolt again.

Putting everything back is just the reverse of the above, requiring a little wriggling to get the pipes back on. I then ran the test once again, to make sure that there wasn't a different reading when the air pipes were back on and all was fine.

I hope that the above is a useful 'Noddy guide'. Feel free to chip-in if you see something that I've done incorrectly or requires a better explanation.

Thanks to all of the people who have previously posted on this and also those helping with my recent issues

Until the next problem...

Bill

PS. Thanks Baffler - I'll go and have a look at the tensioner, but it is all working much better now, including a smoother idle. The timing belt idler adjustment was almost at its limit, so there may be some stretch but I've not tried changing it (yet). As for the cam belt, I had it changed a few years ago and haven't done too many miles since.

[Martin Cox]

Thanks for the update. It's always good to hear how things turned out and often very useful to the rest of us too. Your write-up covers a few practical points that don't usually get mentioned like the need to remove various bits of pipework to actually get at the injection pump belt. It's a useful addition to the collected wisdom.

You can certainly tell the difference when the timing is right.

Well done on getting it sorted.

Martin.

[Baffler]

That is a great break-down of the procedure, Bill, which will be of use to others, although, these engines are getting thin on the ground nowadays, thanks all the same for taking time to write it up!

Just to add...the recommended/optimum timing "sweet spot" of -0.5° is just ever so slightly advanced with minus being advanced and plus being retarded in this instance...as if it wasn't confusing enough

Originally Posted by Martin Cox

Rudi Dudi claims to be able to tell when these engines are timed correctly just by listening to them

Some say that he eats DiCE for breakfast and that VIDA should be afraid...be very afraid

[brickman]

Litens aren't as great as they used to be, last few cars I've done with LITENS timing belt kits, the tensioner (cam timing side) has had noticable play in it from new, fitted anyways because 'maybe its mean't to have some play' and the timing belt will run to the inside or outside of the pulley badly. Replaced with old tensioner bearing and belt sits bang on with no noises or movements during change in RPM.
Reported it twice to Litens, who basically reckon I had a fake one, so sent them photos of packaging etc and then nothing. Same retailer/parts company I've been using for 15 years. Main difference is I think Litens is a Canadian company and used to have the bearings made there or somewhere else in Europe, now they are stamped 'made in romania', and its since then I've had problems (4 kits in total with faulty bearings).