2 T4s and not a clue
 

Hi, I currently own a 2002 V40 T4 automatic and awaiting delivery of a 2004 S40 t4 Manual. The V40 I bought back in October with 108k on the clock and up until the guy before me got his hands on it, it had been very very well kept by its previous owner of 17 years with full services every 6 months with alot spent replacing just about everything. The only thing that has never been touched is the turbo which brings me to my problem. In the last month or so its developed a noise which doesn't resemble any sounds nor any symptoms of a blown/faulty turbo that I know of. Now I will say I'm no mechanic and after 10 years of being in the RAF and having not much interest in cars I am fairly new but not un-teachable, so by all means it could possibly be a faulty turbo i don't know hence why I'm here and since all my mates have no interest in "boring rustbuckets" i'm on my own. The best I can describe the noise is when you hit around 3000rpm a "stuttered induction" sound happens. No whining, whistling, crunching or any smoke at all and it still pulls very well, even being still good for 140. Now the guy who owned the car briefly between the careful owner and me looked like he had been through a few bushes and ditches in it with all the scuffs and scrapes so I do know it has been abused for 6 months covering nearly a 1000 miles a week for the entirety he owned it, but even with that said it has been spot on up until recently. And then today a new one! When i pulled in from work, as soon as I engage park the engine started revving without revvkngbif that makes sense? I engaged drive and then back to park and it was fine? Sorry for the life story but yeah any experienced opinions would definitely be appreciated and anything to watch out for regarding automatics or the s40s would be appreciated also.

Cheers

Callum

Check for air/vacuum leaks, the 3k sound is possibly related. Are you replacing the V40 with the S40?

Mike

Nice one I'll have a check when I go back over the unit Monday. I had a quick check last week but I was in a rush and with not that much knowledge i spent most of my time educating myself on it rather than diagnosing much, and no not replacing the v40. The V40 is my Mrs' and now its off the road to be freshened up a bit she'll be using the S40 for the time being and then it'd be a case of deciding the S40s future.


Callum

i would cheek the one way valves from the fuel tank vapor system.. one faces inlet manifold and other on goes in before the maf....they are on a t pipe coming up by side of the battery...

Nice one I'll have a look into that too.

Hmm....is it possible the previous owner had a manual boost controller fitted? As said check all the vacuum hoses, their condition and connections.

Apologies for the delay in the update, as you're about to read the last week or so has been a nightmare...

So we start with Monday last week, the day I was meant to be taking the V40 apart, my Mrs went into labour and instead I had to spend the best part of 3 days back and forth the hospital in the V40 (s40 hasn't arrived yet) and all was fine to the point where even the previously mentioned noises had disappeared. Then 2 days ago on my way to putting the V40 into storage, it developed quite a few problems all on the same trip, to the point where I turned it around and just came home (my lock up is 50 miles away I didn't fancy breaking down in the middle of nowhere). Firstly, for the first time since I've owned it it had a slow vague start, followed by a ticking noise once started. The ticking noise then disappeared when I engaged D and all seemed fine. After around 40 minutes of driving and I don't mean hard driving, I mean very careful driving, I started ascending a steep hill accelerating up to around 40 and the catalytic conv went. Although it took me a few seconds to realise because nothing changed in regards to the how the car felt I could just smell it. I pulled over, foul burning smell coming from the exhaust and a slight ticking sound, so I thought I'll wait half hour for it to cool down a bit and I'll try make it home. (please bear in mind where I was I had no phone reception all the way until I was pretty much home and I was a lot closer to there than anywhere else.) As soon as I turned the key without actually starting the fan instantly came on, (even though I had let it come on before switching the engine off and this was a pretty cold day. Forgive me if this is normal but after 4 years of having these v40s it's never happened) and then upon start up the DSA light on the dash came on and Whenever I engaged P N the car would not idle good atall, the car would slowly vibrate pretty loudly to begin with and then fade out to the point it sounded like the car was going to die but as soon as I engaged D it was fine. Even when i was sat with my foot on the brake in D for a few minutes it sounded completely albeit a bit louder because of the exhaust. So I made it home with no more issues during the drive, the car drove fine, I could hear the turbo making it's stupid noise it's been making and in all honesty it was still pretty sharp even though It sounded slightly louder. Then as soon as I pull up outside, I engage P and the car does that bad idling but this time accompanied by a faint splutter from the exhaust.

Since then I've loaded it on a lorry, put it in storage and I'm not driving not going near it again until the headache of all that clears. In the meantime, any advice on where to start as by the looks of it it's not just the turbo that's bad, would be greatly appreciated.

Cheers

Callum

Not as far as I'm aware, the owner before me spent more on door grease than he did the mechanically and the owner before that changed pretty much everything with some regularity, everything except the turbo, gearbox and Exhaust.

Callum

There's a lot going on there, Callum, so without seeing or hearing the car it really is rather difficult to diagnose. In saying that the first thing that springs to my mind is a duff Engine Coolant Temp sensor, therefore, the ECU thinks the engine is cold all the time so is chucking fuel into the cylinders which leads to unburnt fuel entering the exhaust hence why your cat got so hot. A duff ECT will dramatically affect the idle and send incorrect values back to the ECU hence your fan coming on.

My first task would be to test the ECT sensor and its wiring, replace if necessary and clean the Idle Air Control Valve and Throttle Body butterfly valve for good measure. All the "how to's" are here just do a search for same.

You mention the previous owner of 17 years replaced just about everything but were these components replaced with new genuine Volvo items, reputable OEM replacements or the cheapest option possible?

I should also state that if you intend on running two of these beasts I suggest you invest in a copy if VIDA, familiarise yourself with how this engine and its components function, and also a DICE interface in order to communicate with the vehicle.

Oh and congratulations on the new arrival! Hope mother and baby are doing well!

As a small note to add. The default position for the ECU if it detects no thermostat signal is to turn the fan on to prevent overheating which it wouldn't be able to detect.

I had one fail on my 2.0T which played about for about a week before it finally went. The car was mucking about with erratic idles and odd throttle responses prior to it obviously getting such spurious signals it shut down to prevent damage. Would not restart properly, or run for more than a 20 seconds.

I tried disconnecting the connection to the thermostat and the fan instantly came on, I assume to protect the engine, and the car ran on some default settings and was driveable.

For your turbo noise you might want to check the manifold nuts, they do come loose on these turbo engines for some reason, when I brought mine I think 3 were missing.