Escaped horses on '96 855 Turboveg
 

Evening all

Following an afternoon of tinkering, I thought I'd throw open my current ponderings to the Volvo collective. I've used this site passively for many years, but my time has come to seek direct advice!

My car is a '96 855 TDI with 257,000 miles on the clock. Whilst it still runs fine (touch-wood), I have noticed that it has become less spritely over the last year and there is less of a kick when the turbo comes in.

The 'only' modification I have made is that it has been running on recycled veg oil for the last 30-40,000 miles (~3 years) with a twin-tank set-up. the performance is the same when it is switched to diesel or oil, though it is somewhat smokier with oil. Fuel consumption doesn't seem unreasonable, but I don't track it accurately due to the duel-fuel arrangement.

Things i've thought of/checked so far are:

Recently changed the air filter (reduced smoke at idle).
Listened for the turbo - It's still there and does have some effect!
Checked the air pipes - Couldn't see any obvious splits/leaks.
Blanked-off EGR valve (quite a while ago now)
Tried unplugging the MAF sensor - Went a load slower until plugged back in and Lambda light came on for a while!
Tried swapping the MAF sensor from another car (same model) - No major effect, but not sure if the ECU needs time to adjust. unfortunately I've now sold the other car so can't test further.
Tried injector cleaner in fuel.

I'm thinking that if it were an injector related problem then it would result in a lumpy idle (it's pretty smooth) - Is this an incorrect assumption?

What are the symptoms of a weakening turbo - Are there any easy tests to check boost pressure?

Would any of the above (plus MAF sensor) show up as error codes on the ECU? I've been trying to get a ODB2 cable to work this afternoon with either the VAGCOM or VOL-FCR trial software but haven't had much luck yet - Could be the usb lead I have or a more fundamental compatibility problem as there is conflicting information on t'inters about whether you can run diagnostics on cheap home set-ups for this model and year.

I was also wondering about pump timing, which could be checked with Vol-FCR.

Any thoughts for what to check, or overwhelming recommendations to have it checked professionally welcomed!

Kind regards

Bill

Watching this thread as I have a similar problem.

855 TDI is gutless under 2000rpm, then it kicks to life but doesent pull no way near as strong as she used to.

Oil and air filters etc recently serviced.

No warning lights.

Pump timing not checked yet, cant check MAF as have no spare. IIRC MAF was swapped shortly before i bought the car for a breakers yard part as the seller said it was giving problems, plus I've had problems with it previously.

Anybody know where we can buy a new MAF for the 850 TDI as it is different from the MAF on the V70 TDI with the same D5252T engine.

To add to my 'problem', I'm now having difficulties starting. It will turn-over, chuntering occasionally but can take a few fairly lengthy cranks before it fires (with plenty of smoke!). Sometimes it's okay, but it doesn't seem to be a function of engine temperature.

Does the above support my thought that the timing needs to be checked/adjusted? I've had another go at checking it with Vol-FCR, but I can't get the interface to work.

I'm now debating whether to get the timing belt changed as it is due - However, I'd like to explore the above first so that I don't spend lots of money if there are other underlying problems.

Any thoughts?

Thanks in advance

Bill

sounds like the pump timing, if you have the trial software it will not do the pump timing for you you will have to purchase the full version.hope that helps
mike

yep definately sound like pump timing.

OH YES!!!!! I can categorically state IT IS YER PUMP TIMING ..

I have just had mine re-timed & it starts BRILLIANTLY & Pulls like a Train .. ALL D5252T Engine MUST have their Pump RE-TIMED when a new Cam Belt is fitted (it only takes a movement of 2mm (YEAH I DID SAY 2mm) for problems like yours to manifest themselves) the timing should be + or - 2 degrees .. a movement of 2mm on the timing pulley can through it out as much as 50 Degrees!!!!!!!!

PLEASE NOTE THOUGH .. your ENGINE IS NOT A D5254T (Its WRONG in the drop down list on this forum) its a AUDI D5252T. a D5254T DOES NOT EXIST!!!!

Keith

A B5252T exists but is not this either.

Its a D5252T.

D means Diesel, (B for Petrol [Benzine]), 5 means no of cyls, 25 is the displacement (2.5 litre) and 2 is the amount of valves per cylinder, lastly the T is the aspiration (Turbo).

Yeah Sorry mate .. I confused my "B"'s with "D"'s ... Edited now correctly

Software that does the pump timing? Enlighten me please? Can I get this for the D24Tic (non common-rail)? I've got Vardis and the green books, I've never heard of software to do pump timing

This is TRUE Laney .... Basically the Engine itself times up the pump (Well it tells you it "Out" ect & by how many Degrees ) & then you adjust the Pump Pulley Accordingly !!!! & Re test with the softwear

And the D5252T Is NOT COMMON RAIL Either but I don't know if it applicable to the D24Tic


Keith