850 TDI - idle revs

Hi.
I have an 1996 855 TDI with 250000kms. Started a month ago - when idle,
revs go up & down a bit (I'd say less than 50 revs). It happens only
when the engine gains working temperature (after driving for about
25kms). And it doesn't happen every time (?). And few days ago, the
lambda sond light went on for the first time (which on TDI indicates
some problem with electronics, since TDI doesn't have lambdas), but it
didn't happen again. Didn't notice any other problem - car goes well...

Please, tell me what can I expect it to be? And what price range?
Unfortunately, I don't trust any of my 3 local Volvo specialists :-(

Any clues?

Thnx very much.

 

I can't really help you except to say that if the Lambda light came on,
then the computer should have a code stored. Get that code read and
it'll point you in the right direction.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Maybe Audi specialist?

 

You might have a leak either in the diesel filter connections/fuel hose or
in the vacuum regulation
system.

The lambda sond going on/off can be from a lot of things - I had the same
problem with my 850 TDI but it
disappeared when I cleaned the cable connectors to the airmass unit and to
the EGR valve vacuum control unit.

Best regards Per

 

I didn't know diesels had lambda. What does it do?

Mike

 

No - no it doesn't... The warning light on 850 TDI has the same lambda
symbol as a gasoline version, but it only warns about some (could be
many things) electronic failure - problem... I said that already - just
look at the beginning of the post... I learned that from my owners
manual

Cheers,

 

Well I don't trust any specialists in my city
Just being paranoid, and don't want to get ripped off

Besides that, I am not sure if the Audi workshops can check "their own"
engine in 850 TDI. Anyone knows that?

BTW, I am planning to make an OBD2 kit with some help from my friend...
Then I should trust it

 

I hope it is something like that It is certainly on the cheap side
I'll doublecheck everything.

Thnk you very much - you've been pretty helful! Can you by any chance
point me to some links on the web where I can find information (and
possibly images) about those things? Where they are in the car and so on?

Hmmm - I'll try the next one

What is the sparkplug lookalike thing situated on the far right (looking
from front) side under the hood between the battery and the fusebox? It
has 3 plastic (one yellow, two white) small diameter hoses coming out
of it?

After one service, I had similar problems cause they didn't put one
white hose back where it belongs to (air intake I think)... When I have
put it back everything was OK after just a few minutes...

Sorry for the long post and thnx for the tips!!!

-
Drnya

 

Ouch - my mistake. I'll try to read better!

Mike

 

On Volvos (and most Asian and European cars), only your country gets the
"check engine" light. The rest of the world has adopted the lambda
symbol. Some cars (primarily American nameplates) in Canada have "check
engine" lights, Volvos did when the lights first came out.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Check lamp on/off for lambda sond:
Look for cracked hoses and if hoses has becomed hard and untight. The thing
you
describe could be the EGR valve vaccuum regulator. Has the EGR valve
ever been cleaned? The plug is placed under the unit.

I had the same problem once with the white hose missing in the air intake
after service also
the plug to the EGR regulator was not connected.
If you find a leak remember to disconnect the negative battery pole for 30
min. to restore the ECU
values - it might be running with some default values.

Best regards Per

 

No. If you have time, could you please give me very short instructions
on how to clean it? Is it safe to mess with it, or maybe very sensitive?
Should I use air to clean it? Or some liquid?

Are there any links on the web? I found some on changing belts, struts
etc. But nothing like this...

Didn't notice any leaks so far... I will inspect it more when the
weather turns warm It has been the coldest winter for 40 yrs here.
Very cold mornings... Down to -25C...

BTW, what is the minimum temperature that you have started your 850 TDI?
And how many kms did you do with your car... How many kms can I expect
from that engine if I take care of it (of course)? I bought the car 2
yrs ago with 180000kms. Now I have 220000kms...

Thnx very much again and sorry for so many questions.
I wouldn't mind very short answers

It is easy to find info on 850 gasoline models, but not on TDI :-(

 

See my answers below...

....You can search for illustrations on the internet - does not have to be
volvo.
Use eq. carburator fluid to clean it - should be pretty easy.

....Information on the 850 TDI is very limited I use Volvo Vadis software you
can find
it on ebay. I can also recommend the VOL-FCR software for testing, is cheap
as well,
you can buy an ODB2 cable to connect on ebay as well.
values.
......anyhow try to disconnect the battery to reset the ECU.

...... minus 25 degrees celcius but with winter diesel - suggest that you add
20% petrol
to your diesel when tanking.

And how many kms did you do with your car... How many kms can I expect

......Remember to change to timing belts - there are two - and the water pump
at
220000 kms!!!! The water pump is important since it driven by the front
timing belt,
if the axle breaks the engine is gone because the pistons will hit the
valves.
.....Mine has 228000 kms - expect that the engine can do more than tkm 500 -
when
cold never go beyond 2000 rpms. I use 0-w40 oil, Castrol Racing.

......If you still have problems and you have a Bosch Diesel Service where
you live let them
look at the problem. I use a Bosch Garage for diesel pump adjustments etc.
Audi garage is
ok too but they normally wont work with a volvo even though the mechanical
engine is
Audi 2.5 TDI AEL type because the ECU on the volvo is from Bosch where audi
uses Digifant.

 

Thnx a lot Per!

/ I have cut out the repeating bits... /

After your EGR tips, I have found some great repair infos at:

http://www.volvospeed.com/

Will get some of that stuff for sure!

I've been using Castrol anti-gel (injector cleaning) diesel additive
that holds down to -26C. Do you think it is better to add petrol instead?

Very odd - I searched the web and I cannot find any info on that Castrol
additive I am using??? I've been using it for yrs in my old 240 D6
before... Never had any problems, though...

Changed all that even before 220tkm - just to be sure

Yes - I am very causious with that! I extremely rarely touch 2500 rpms,
before the engine warms up. I use Total 10-w40, and change it after
8000kms (and oil filter every time). The engine doesn't waste a drop of
it

Thnx again Per!

 

I only suggested petrol/diesel mix because it is cheaper than additives! I
use additives from
time to time as well when my engine start to smoke a litlle when driving to
much in town traffic.
This engine type needs to be driven hard - above rpms 3500 - once in a
while to stay clean inside.

Regarding the oil Volvo generally changed the recommended viscosity from
10w-40 to 5w-40
in a service bulletin. Do not know Total make sure this oil conforms to the
VW NORM 505 00
if not, do not use it. My engine is tight as well using 0w-40.

Best regards Per