Hello everyone,

I just joined the forum today. I have a skoda octavia 2012 model with a 1.8tsi cdaa engine. I have been having a few drivability issues lately. The exhaust gases exiting the tailpipe are extremely hot. I cant even keep my hand in front of it for more than a few seconds and i am also having misfires on load and the car generally feels down on power. There is no smoke from the tailpipe on cold starts and it starts quite quickly. I dont have any codes except a cylinder 3 misfire(P0303). The exhaust gases werent this hot before. Even when the engine was hot,you could still not feel the heat of the exhaust but now it is ridiculously hot. Should i be concerned about this? I have read a few articles where they say that the exhaust gases should not be so hot. Could this be a sign of a clogged cat or a restriction somewhere in the exhaust?  Please provide your valuable insight on the problem. The car runs fine on light throttle. Only when you try to accelerate suddenly,it misfires. The dtc shows only cylinder 3 misfire but the misfire counter shows that more than one cylinder is misfiring. I request you to kindly  provide your valuable insight on the problem. Thanks and cheers. 

Welcome to the forum.

?

How many miles / km has the car done.

When were the spark plugs looked at or replaced?

Just a thought, have you lately  measured exhaust  gases  to see what the values do say? 

I believe you'll get info and also for  the cat condition.. 

9 hours ago, Roottootemblowinootsoot said:

Welcome to the forum.

?

How many miles / km has the car done.

When were the spark plugs looked at or replaced?

 

and if the plugs were done recently were they gapped properly?

 

if you do have a misfire the excessive heat could be unburnt fuel combusting in the exhaust system or cat. 

 

from Ross tech P0303 error code.

Edited 27 April, 20206 yr by mac11irl

The plugs are brand new original audi ones. The ignition coils are also brand new red top coils. Actually a few months back the timing chain tensioner gave way and the pistons hit the valves. I got the entire timing kit changed and rebuilt the head. The garage where i got this done hadnt done a good job so i got it rebuilt again. The head was rebuilt again and the engine was retimed. Its just that ever since the timing job was done,i am facing this problem. But in the new workshop where i recently got it rebuilt,they did the job perfectly and i have changed piston rings too. I dont have any oil consumption issues or anything. Even on a very cold start there is no smoke, so i thought it could not be anything mechanical. It starts fine,runs fine on light throttle. Only when you need more power and accelerate,it misfires. I tried disconnecting the vvt solenoid to see if that might be causing the problem but the n205 seems to be working fine. And i can also hear the turbo more than before like it is so loud. It wasnt this loud before. In these cars,since the cat bolts on to the turbo,which is what got me thinking if it could be the clogged cat which is stressing the turbo. This is just an idea,i could be wrong. The car has done 63k kilometres and due to the lockdown here,nobody is open to check the exhaust gases. But in the obd2 emission tests it always says the catalyst has not passed. What does that mean?

And i also forgot to mention-My gas mileage is down the drain. It is drinking way too much fuel. All 4 injectors brand new-genuine. Throttle body is clean. High pressure pump is doing its job properly. No fuel pressure issues. This problem only happens on load. Light throttle driving is smooth. 

Too confused.. I believe you need to scan the car with a good diagnostics like VCDS  or any from the repairers to see what else could have been logged into and start investigating at better point. 

just because they are audi plugs doesnt mean they are correctly gapped for your engine.

 

have you pulled them to check the condition of them?

 

also... the maf.

 

and then... the cat may be shagged from the original belt failure.

I had a catalytic converter fail on a 4 year old BMW 523i ...3 weeks after I bought it. £750 lesson learned the hard way! Anyway, you’ll definitely know there’s an issue, your car will be gutless. Hope this helps and that you get a cheap / quick solution. 

From the Op's description, its likely that the engine is running very rich. So rich that the Cat is overheating from unburnt fuel. You may also notice a rotten egg smell if the fuel is not sulphur free. Continue like that and the Cat will be destroyed through excessive heat and/or poisoning.

 

It's running so rich that when accelerating, it's misfiring when the Ecu injects extra fuel. Again more unburnt fuel gets to the cat.

 

It could be down to several reasons.

 

It could be leaking, loose turbo boost pipework or intercooler / inlet manifold, might explain Turbo loudness.

 

Assuming no remap or tuning boxes or modifications, then it could be a sensor issue, MAF or MAP sensor. Check the air filter is clean too.

 

Check the new fuel injectors are the exact correct part numbers for your engine serial number. Iirc replacements must be coded and adapted to ensure correct metering. Check this has been done.

 

OBD2 emission fail is often due to Lambda sensors readings being out of specified range. Probably due to running rich but could be faulty sensors or the CAT is damaged or you have a leak in the exhaust system pre CAT, which could also explain turbo loudness.

 

Edited 27 April, 20206 yr by xman

Yeah when you put it like that it actually makes a lot of sense because i have been getting a loud hissing sound just when the turbo is boosting under load and thats when its misfiring like it feels like the car chokes for a bit and then after 4k rpm it pulls like it should. I have replaced the fuel filter too. And yeah i do have a remap. Its a stage 1 remap no hardware modifications. The strange thing is i can only hear the hissing sound when all 4 windows are closed and the music system is switched off. Just about when the boost kicks in i hear the sound till about 3.5k rpm then it misfires with a flashing CEL. P0303. When the timing chain had failed a few months ago. It gave me a CEL saying P0016 cam shaft correlation some issue and after the light came on we drove for like 120kms and it was totally down on power,i parked the car that night and started it in the morning thats when the chain gave way and pistons hit the valves but there was no damage to pistons and the piston ring and head,timing job was done very well. Fuel injectors are exact same part number 06H906036H genuine vw bosch injectors. Could driving the car for so long after the p0016 have damaged my cat? There is a boost leak somewhere,should get the car up on the ramp after the lockdown.