Engine power problem on 1.9Td AAZ

Post by **brookie** » 07 Jun 2006, 14:44

Where's the best place to start with this one?
I have a noticeable power decrease on our camper, particularly noticeable on an uphill motorway where usually I'd cruise at 70,now I'm struggling to do 63!
I've had the Turbo checked and it's giving plenty of boost and the engine and head are only 12000miles old (new block,recon head) and there is no smoke at high revs, good compression - starts first time.
The injectors and pump were serviced a while back (37,000 ago).
Took it to a diesel specialist today and he wants to start by overhauling the pump at a cost of £250 +vat with no guarantee that will fix it, but he reckons it will.
The cam-belt was replaced at the same time as new engine was put in 3yrs ago and I haven't adjusted this or the pump timing since we've had it because there was no need as it fairly flew along!
Could the pump timing have "moved" over time - wear for instance?
What are the cheaper diagnostic things I can try first before committing to a large bill?
Other points; Fuel filter changed 2000 miles ago
Air filter changed 8000 miles ago
What should I look at; pump timing,injectors?
Appreciate some good free advice!
Thankyou. Rob

Post by **crazydiamond** » 07 Jun 2006, 14:53

Silly thing, but is the throttle cable giving you full bore when you floor it, get someone to press it (with engine off) and look to see if its at the stops on the pump. It might just be cable adjustment (thats cheap)

I had a 1.6D years ago and this happened, quick adjust and all was good for a 1.6D anyway

Post by **brookie** » 07 Jun 2006, 15:37

Thanks Crazy for that idea about the throttle cable. Have just checked it with a willing helper and I've got a gap of about 1.5mm at the max stop. HOPEFULLY this is what's causing it, I'll adjust it tomorrow and let you know.
Cheers
Rob

Post by **Diamond Hell** » 08 Jun 2006, 08:43

Air filter changed 8000 miles ago

What sort of filter is it? That could be quite a long time since it was changed.

Turbo diesels love lots of air, so if there's filth and smut blocking up your air filter that could be what the problem is.

Not as cheap as cable adjustment, but something else worth chasing down.

Post by **brookie** » 08 Jun 2006, 19:11

Have now adjusted the throttle cable so it reaches max stop with foot down and it throttle response is much better (taking out the slack I imagine) but unfortunately max speed is still about 65mph.
Will get a new air filter in tomorrow - thankyou for the suggestion Diamond. The one that's in there is a Man filter which I got from JCampers. Are these not up to much? I was planning on changing it at 12000 intervals - is this too long? If this air filter change fixes it I will be changing it every 3K! Fingers crossed and ta!
Rob

Post by **Ivorblueun** » 09 Jun 2006, 21:29

I always give the air filter a good optical B*!!*((ing at the same time as i do my oil change as its one of those things that depending on the enviroment you've been in depends how bad or not it is, so if it looks full of cr@p change it

Post by **HarryMann** » 10 Jun 2006, 01:37

After checking the filter... if no go

Run something like TEC 2000 or similar (injection cleaner) through it - will give the pump and injectors a good clearng out.

2nd hand pumps can often be had for 'ess than £100 from VW spares suppliers..

Failing that, your first port of call might be a compression test to make sure all is well. The valve gear of these engines is not beyond question, have a bit of a rep with shims and stem-seals, though unlikely in your case.

One thing you could try, if you really are sure the boost is there (a permanent cab gauge is handy), circa 7.5 psi before the wastegate opens, 10~12 before the blow-off valve goes - is increasing the fuelling by winding the main fuelling screw in a bit (1/4 turn) - as a test, if this peps things up and starts to produce a bit of black smoke by 1/2 turn, then at least you know the score - she isn't getting enough fuel.

What boost did they say your turbo was giving? - or didn't they?? A figure is worth paying for - 'just it's OK could be meaningless. You want to see the boost pressure when you are stuck at 65 mph... what are your revs at that speed by the way?

Post by **"WEAZLECHIN"** » 10 Jun 2006, 19:24

i think the pump timing can slip as there is no woodruff key, it just fits on. bizarre

Post by **brookie** » 13 Jun 2006, 10:58

Thanks guys for the wealth of info re my power prob.
Things are improving now that there's a new air filter in - will hold 70 on the flat which is like my benchmark for motorway cruising. I will now change that air filter every 3-4 k and not 12k.
Put a bottle of Comma Diesel Injector Cleaner in for good measure so will see how that improves things over next week or two.
I'll get the pump timing checked to be double sure everything's where it should be.
As for revs at 65mph I don't know as I have no tacho, but did try slaving a Tim Rev Counter in using the "W" terminal from the alternator but couldn't get a reading. Has anyone fitted an after market tacho to a 1.9Td AAZ diesel? Can it be done?
Thanks for helping and if anyone knows about the tacho please tell!
Rob

Post by **Diamond Hell** » 13 Jun 2006, 11:05

A standard 1.6TD tacho should work fine.... now all you have to do is find one!

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