S40: Another troublesome T4

[smashey]

Hi Gang
I have a 2000 model 1855cc T4 which is having problems. I'm hoping that by describing all the symptoms the forum can point me in the right direction. The problems seem common enough individually - and have a number of causes - but grouped together may point to a single common cause?

Problem 1 = Bad idle. From a dead cold start things seem fine with very little hunting, but once the cars warmed up the idle speed seems to vary between800-1100 revs.

Problem 2 = Engine races. Occasionally (usually when re-starting an already warm engine) the idle speed jumps way up and starts ramping up and down between 1500-2000 revs. Lasts a few cycles (just long enough to make me look like a dick at traffic lights) and then returns to normal bad idle.

Problem 3 = "sticky" Acceleration. No real hesitation when accelerating (gentle, normal town use) but a reluctance to release after I take my foot off the gas. Times vary but I'd guess about 1 seconds delay in deccelerating - sometimes a bit more. Again this is an intermittant problem but becomming more frequent.

Problem 4 = Poor Lumpy acceleration under load - Misfire? Seems to be a common thread! Gentle acceleration through the turbo range (or medium in low gears) seams fine but demand the power under load and the engine feels like its misfiring or being starved of fuel. Yes it's still the original fuel pump AFAIK.

The car has just hit the 100K Miles reading. Up until 82K, early 2007, it had the luxury of full Volvo servicing. From then I ran it up to 99K by the end of that year before taking the car off the road. The problems started around 92K and I didn't have the funds to get things sorted. Problem 2 had occured before (around 60K I think) but the garage sorted it quickly. The Garage closed down last year so I can't even check on fault history.

Now I've had to put the car back on the road, so looking for advice. I'm reasonably technical once they started using fuel injection and ECU's I was out of my comfort zone.

Thanks in advance - Mike

[960kg]

.......you should really have a scanner and read the error codes, then and only then will you have a 99% chance of a remedy.......by what you are saying they are the exact symptoms i have when a garage put a non Volvo cat .on my 960, also standing at the back of the car on idle the fumes from the exhaust were quite vile the smell of unburnt unleaded with black swirling smoke....the O2 sensors finally gave up and this was at 103,000mls they can go anytime after 60,000 according to reading about them, so at your 60,000 you may of had the start of it,who knows?......but as time goes on the situation gets worse and also the petrol consumption....imo, if this is combined with heavy fuel usage then it may well be the sensors, at that mileage doing both would then get you part of your money back as a lot less petrol is being used but the greater performance of the engine would be the best reward..........

[allandwf]

Oh no, do I see the start of another "scanner" thread?

[smashey]

Thanks for the quick reply 960kg...

I'm pretty sure the garage didn't change out any part of the exhaust system at any time. When they sorted out problem 2 for the first time the car was only round the back for 15 mins and there was no charge.

I'd say the fuel consumption is slightly high, but there's no signs of smoke, and the fumes seem normal at idle. Could still be the O2 sensor of course.

My worry is being a closed system with a whole load of sensors pumps and valves involved, I could end up changing nearly everything out before hitting on the culprit.

There's no guarantee that these symptoms are all from a common cause either, but that's what me and the bank manager are hoping

Cheers - Mike

[Baffler]

Do try to get the codes read as 960kg says.

The racing revs could be a vacuum pipe leak. Check every hose/pipe for cracks.

Have you changed the obvious? Spark plugs (use genuine Volvo plugs only!), fuel filter, thermostat.

Engine/coolant temp sensor (on the thermostat housing) could be sending out incorrect messages to the ECU.

As you probably know fuel pumps are suspect around the 100k mark. You could, as a temporary measure, remove it from the tank and clean the filters on the bottom of the swirl pot.

Oh and clean the idle control valve and throttle housing at every service.

[thebigv]

I second what baffler says, oh and only use Genuine Volvo fuel filters too, had problems with aftermarket

[smashey]

Thanks to all for info so far.

I have a mechanic friend (non Volvo) who'll be able to get the codes I guess - is it a standard connector for this? I'll also pass on your comments to steer him in the right direction. I've got plugs on order and I'll have a look at the fuel pump filter.

I'd rather not buy a complete Volvo fuel pump if I can get away with it. Have any of you tried the Walbro conversion?

Not sure when the fuel filter itself was last changed - is this an easy job.

Finally - as I'm working from a Haynes manual which doesn't really show T4 parts locations that well. Where could I find the idle control valve & again is it easy enough to clean?

Thanks again - Mike

[allandwf]

A search on here should find you an idle control valve cleaning thread, with pictures, was really helpful, and it's an easy job. As for the connector these were standardised from 2001, so your 's may not be.

[gmain1967]

Hi

Just to help you quickly, here is a pic I took for someone else on another thread, but which shows where the ICV is, on the T4 engine. This is looking from the passenger side, and it is under the cover at the left of the picture.

To remove it, take the cover off (may be a torx bolt, or a screw), then remove the connector from the end by pressing the metal clip in towards the connector, and pulling downwards. The ICV looks like a silver cylinder.

Then remove the two torx bolts that attach the ICV. You can now pull it free and clean it, and the throttle body - carb cleaner is good. If you really want to be thorough, remove the motor from the ICV as well, it's only another two screws.

Refit is simply reverse of above. Hope this helps.

[Vinnyman72]

Now then,
Ive been having similar problems, roughish idle, hesitant / misfiring accelaration under load, started considering changing fuel pump / filters etc.. Had changed plugs and one coil pack, seemed to temporaily fix it but then it came back again, was getting really sick of it anyway last night i took out all the plugs, all leads and coil packs, discovered that my second coil that hadnt been replaced had a small crack in it at the bottom of the shaft, i soaked all the above in petrol for half an hour and then thoroughly cleaned them, gotta cotton wool bud into the plug leads ends and removed a small build up of crap that had built up on the conductive metal that sits over the plugs, stretched out the spring in the coil packs so was petruding abt 8mm from the bottom of the the coil shaft, they werent petruding at all before... Then left to evaporate for a couple of hours, give a quick run over with a lighter to burn off any residue and to save blowing my motor up AND HEY PRESTO !!!! It runs like a dream again, better than its ever ran since ive had it over the last 3 months, hitting 0.9bar with no probs at all which it struggled with before, im sure it all lies in the connection of the plugs leads, get the crap cleaned off and you maybe lucky like me... Good luck to youn pal !!! Vin.