1999 Auto V70 Engine Runs Like a Pile of Rocks
 

Evening all, I have an 1999 Auto V70 XT Engine Model B5244S2 i've had the car 5 years and from day one she always wanted to gag and jump forward with the foot-brake on - Volvo told me they could not identify the fault - that was the last they saw of my cash.

Then about 12 months ago i found that i could drive without a problem 60 miles down the motorway but that now and again the first roundabout or hold up the car came to the engine would deteriorate to such an extent it was as if all five pistons were fireing in some sort of random chaos!

It was suggested that it was the ETM - I gave it a good spray clean and all seemed well for a week or two but i think it was just a coincidal improvement.

It now seems that as soon as the temperature comes upto the 3 Oclock position and the car comes to a stop at lights or a junction it goes lumpy and the revs become slightly erattic.

So seeing as it seemed as though it was an overheating issue i checked the thermostat, the temp sender unit, fan and relay all seemed to work except the fan never seemed to run unless the sender unit was disconnected - this makes the fan run constantly and keeps everything cool but although never going into major lumpy mode presumably coz it doesn't reach high enough temperature it is obviously not that happy when first setting off.

Sorry about the essay but hopefully one of you guys might be able to point me in the right direction.

Please Please Help!

ATB Pozzouk.

first thing to check is all your vacume hoses for splits/holes, when was the last time it was serviced? spark plugs changed? fuel filter changed?

Failing that lot you really need to find some one with Vida Dice who is prepared to diagnose the problem and not just a 5 minute job, but someone who will test the various sensors including ETM

Idle air control valve?

That only works when the engine is idling, and if it's broken or dirty, or one of the hoses is split, or there's a dodgy electrical connection, then the car would certainly show the sort of symptoms you're describing.

Cheers

Jack

I wonder by any chance there is anyone in the Pompey area that might have such kit - i did purchase an Autel Code Reader that flagged up a a few problems but it doesn't seem to recognize the B5244"S2" engine Model.

Off to check for air leaks as suggested - while at it, is it possible a grubby mass airflow might cause problems as i never have cleaned it as not sure best method???

Last off - where is the idle control unit???

Thanks Guys.

As you car has an ETM then it won't have an idle control valve, it will have an assisted air valve. This bypasses the throttle body with air which is diverted though some trunking and allowed into the inlet manifold around the fuel injections to help emissions at idle. It could be the valve is a bit blocked or the trunking is leaking.

As has been suggested look at all the inlet pipework for leaks and clean the throttle body and assisted air valve.

If there where fault codes logged what where they?

Cheers Chris,

Sounds like a can of good cleaner (any type or make - suggestions welcome) and a thorough search for air leaks in order + a set of plugs!

Talking of parts - any idea where the fuel filter is hidden???

Thanks again guys - at least i live in hope that i'm going in the right direction.

ATB.

PS. Will come back with the codes later.

When you clean the ETM you are cleaning the side nearest the engine and not simply spraying cleaner through it?

To effectively clean it out it needs to be unbolted from the inlet manifold then you can get at the side that gets carbon build up - Mike

Just to add to Mike's comments, the important thing to clean is the edge of the butterfly and the corresponding part of the bore. The issue is that the 'gap' gets clogged. This is what you need to make sure is clear.

How did you test the temperature sender?

It sounds to me as if this is faulty, constantly telling the engine it's cold, therefore making the mixture rich, which will make it run lumpy, especially at idle. The reason I say this is that the fan only comes on with the temp sender disconnected. This is wrong! The temp sender sends its signal to the ECU, which in turn tells teh fan to switch on, so it can only really be sender, wiring or ECU, in that order with sender being VERY much the favourite.

Sorry to question your diagnosis, but we need to be quite sure you have properly eliminated the sender.

When running the car, when its hot where is the needle on the temperature guage?

Sorry to disagree but the engine ECU will always start the fan when the temperature sesnor is disconnected.
The op said the problem starts when the gauge is at 3 o'clock this suggests to me the mixture is weak at full engine temperature, probably due to an induction air leak.