Hi all,

I have a strange problem that has developed shortly after a service on my Diesel Skoda and the garage are a bit at a loss as to what it might be – thought I would give you all a try!!

Car drives absolutely fine until I try to pull away from something like a roundabout, usually in third gear, and I lose power and see dark smoke.

Now – the reason this is strange is it ONLY happens when accelerating whilst turning right. Hence the roundabout thing.

If I come off the accelerator, straiten up and go again, it is completely fine.

Garage have checked all pipes etc. The car is not showing any errors on the computer and so on.

Please, what craziness has happened to my lovely car???

Rachel

Cat AID’s

can i have your bike?

Any hissing? 3rd gear off a roundabout = high load, lack of power & black smoke I’d say overfuelling. Its got to be an air/boost thing. If you’ve got no boost leaks then perhaps the maf, unplug it and see what happens (i assume this would work the same as it does on petrols). You’ll need to reset the light though – have you got vagcom, its your friend?!

It does sound like the car is losing air on the inlet path somewhere causing it to overfuel, but why it only happens when you are turning right, I don’t know….

Could be a broken pipe connection that opens up with flex in the chassis???

err – I don’t know what a ‘maf’ is… 😳

No hissing I have noticed – tried driving with window open but didn’t hear anything unusual. Might not be a problem when engine is cold?

Rachel

MAF is mass airflow sensor (I think). I also think (although could be wrong) that it detects the quantity of air passing into the engine and sets the amount of fuel to be injected accordingly.

The MAF will say you have X amount of air going in, so the ECU needs to add Y amount of fuel. But if you have an air leak between the MAF & the engine, then you will be putting in a lot more fuel than you should be (because you have ‘lost’ air) and hence you get the black smoke…..

Weird. I’d be taking it to a large car park after hours (B&Q or somewhere) and driving in left & right circles at various speeds, gears & engine revs to try and get a better idea of when it behaves how it does…..

Intercooler hose it sounds like….

A break on the wiring to the MAP sensor.

sounds like a poor electical connection to be honest, if its anything like out Skoda the radio cuts out and the indicators come on when you go over a pothole…Skodas are brill cars but they do have their electrical gremlins
I would defo go poor connection to the airflow sensor, if you know where it is unplug it check the condition of the pins and plug it back in securely, there should be a slide pin that holds the plug in place sometimes it comes off…any garage would be able to check this for little cost if you dont fancy it yourself
good luck hope it gets sorted

We had similar in the Micra of Doom, turned out to be the EGR valve. Wasn’t directionally biased though.

Have you asked on Briskoda?

Could be loads of things, but easy to start with the MAF (Mass Air Flow sensor).

Locate air filter housing and then follow outlet pipe to engine. Disconnect plug from the sensor in the middle of this pipe. Drive car with it disconnected and report back.
Hth
Marko

If the hose supplying air between the turbo and intercooler/engine has come loose or has a split in it (maybe you bashed the plastic trim below the bumper on a curb?)then you might get symptoms like this. You would hear a noise like a fan blowing when you accelerate.

It will be a sensor, throttle, air mass, exhaust or something else.

All those went on my Skoda within 3 months of one another.

Skoda’s would be great of they’d buy decent sensors.

Failing that it could be a split in the turbo hose? unlikely though

I would also vote for intercooler main pipe if thats been undone/removed to change oil filter on a service and not properly reconnected followed by the MAF. Unplug the connector leave it unplugged for at least ten minutes then reconnect it, this may reset the MAF to a default position.
You say that the servicing garage have no idea what it is, I would suggest potentially its something that has happened as a result of the service and is normally pretty simple.
On my VW TDi I did start to develop smoking problems from a failing temperature sensor (dual sensor on mine that as well as controlling ECU settings was main temp sensor for gauge). When it failed completely engine went on to fall back mode with no turbo boost at all….
One final thought-check your oil level, has it been overfilled?

If an intercooler pipe is split or not fitted properly in some small way then as the engine moves to one side during cornering it could be opened up. If I were a mechanic I’d pull the engine to one side whilst pressure testing it – if they can do that.

I would have said EGR. Split pipes normally leads to low power and lots of smoke all the time. MAF gives a slow revving engine as the ECU thinks low volumes of air so pumps similar small of fuel.

maybe remove the maf and have a close look at the wires to see if anything looks oddball.

Problems with MAF’s are the sensor wires get covered in dirt when the car isn’t well serviced with a dirty air filter. Dirt passes through and attaches to the sensor wires distorting the air flow readings. I’d still look at the EGR first.

Check oil level has’nt been overfilled.

Thanks peeps – that gives me something to start with!!

Rachel

I’ve got the same engine and had the same problem under the same circumstances, on my Fabia the loom down to the MAP sensor/intercooler (in front of the drivers side wheel) has very little spare and the engine lifts most at the front.

A split hose would make a lot of noise.

Of course it may be something else but I’d check here first. or better yet get it on VAG COM.

I had a problem like this but on a petrol BMW (no smoke) and it turned out it was one of the DSC / ABS wheel sensors.

Every so often it would register that the car was out of control and keep cutting the power. Problem was it didn’t log the issue, even though the DSC light would be flashing away on the dash, and it was in the garage about half a dozen times. All eyes were on the DSC but without an error code they didn’t want to do anything. Finally it logged an error and it was rectified but it went on for 6 months or so.

I’d go with checking the oil first like supertaky says, other than that the EGR valve is a good place to look, but my assumption is based on the car being fine before the service. Please don’t just go back to the garage & say it was fine before you serviced it unless you are 100% sure, nothing puts their back up more than some prat that says all was fine before the service but it turns out to be a long standing fault, it’s a sure way to get charged double for the subsequent fix! Believe me I’ve been there 🙁

Good luck.

Mine di that for a while, not while turning right though!! I found gunning it in thrid foot to the floor cleared it. I thought a block in the exhaust….. ❓

What’s the thinking on egr people, that it’s stuck open? I suppose that is a possibility. Boost leaks are generally obvious so maf/inlet or egr then. I think you can get hold of vagcom for less than a tenner these days, find a quiet roundabout, make the car do its thing for 5/10 secs (which should be enough time to log fault), read the code. Or pull the maf, see whether it still happens, or as above, get over to briskoda!