Misfire or.......?

[Qubit]

Hoping someone can maybe give some insight into a problem ive got (otherwise i fear its the knackers yard for my old vrs).    2 garages have been unable to help. 

 

My car seems to have developed a slight mis-fire (or similar).  Ive run it with the MAF disconnected (no different- plus replaced 6 months back) and re-cleaned my throttle body (no different).  Ive also tried 2 spare coil packs (but old, so could still be bad) to no avail, one made it much worse the other no different.

 

There are no codes and neither garage thinks there's a leak anywhere.   One recommended a new turbo.      Im going to get a brand new coil pack from my local dealer in the morning and see if that helps.   Other than that what can i look at - new plugs maybe?    (wiring to the coils looks ok but who knows).  

[mac11irl]

Did you go aftermarket or genuine on the MAF sensor? If AM, it could well be nackered, vag engines like oem sensors...

Main MAF symotom though is a lumpy idle bouncing around a bit in the revs rther than a mis fire.

Edited 5 May, 2016 by mac11irl

[YellowCar]

Sounds like coil pack/s to me but without a code it's a case of crossing things off I guess. If coils and plugs ie spark turns up nothing, probably wise to look at fuel delivery and airflow. Could be maffy as suggested, could also be an air leak or even a dodgy coolant temp sensor messing with fueling...They would be the main suspects but like I said it sounds like coils to me. Try the new coil in each cylinder see if it goes away (could be more than one playing up mind).

By the way, who suggested a new turbo? Sorry but that made me chuckle. I assume the misfire is the only issue?

Before anything drastic think basics, spark, fuel, air.

By the way when one of my coils started playing up in my old Seat it didn't throw a code.

Edited 5 May, 2016 by YellowCar

[Qubit]

Did you go aftermarket or genuine on the MAF sensor? If AM, it could well be nackered, vag engines like oem sensors...

Main MAF symotom though is a lumpy idle bouncing around a bit in the revs rther than a mis fire.

 

MAF was a used but functional one, has been fine ever since and runs no different when unplugged ( no guarantee i know).     I doubt its the MAF, last time i had problems last year it idled poorly like you say, but no sign of that this time.   

Edited 5 May, 2016 by Qubit

[YellowCar]

Lumpy idle can be down to an air leak

[Qubit]

Sounds like coil pack/s to me but without a code it's a case of crossing things off I guess. If coils and plugs ie spark turns up nothing, probably wise to look at fuel delivery and airflow. Could be maffy as suggested, could also be an air leak or even a dodgy coolant temp sensor messing with fueling...They would be the main suspects but like I said it sounds like coils to me. Try the new coil in each cylinder see if it goes away (could be more than one playing up mind).

By the way, who suggested a new turbo? Sorry but that made me chuckle. I assume the misfire is the only issue?

Before anything drastic think basics, spark, fuel, air.

By the way when one of my coils started playing up in my old Seat it didn't throw a code.

 

Yeh could be all of the above eh!    Love the 1.8t    There are no other symptoms that would indicate turbo issues to me, no whine and no excessive amounts of white smoke from the exhaust, but she does have a few miles on her so its not impossible.    I think the coolant temp might possibly need replacing as its always taken slightly longer than my previous 1.8t to get up to working temp, but never seems to have had an issue because of it.    Guess ill add it to the list!     Ill try the coil pack first and maybe the plugs after that.    Cheers

[Qubit]

Lumpy idle can be down to an air leak

Sorry think i confused folk a bit, theres no idle problem at the moment, but there was last year when the MAF proved to be faulty.   

[YellowCar]

I don't think you'll need to look much further than the coils (hopefully), but yes it's a bit of a list otherwise. As said without codes and logging it's a bit tricky, coil packs are quite a common vag issue. Let us know how you get on anyway and will work through the list!

CTS is a pretty cheap and easy swap, would be worth doing anyway...

[Qubit]

Quick update, plugs changed and a coil pack swapped round to no avail, i have got a definite old coil pack thats faulty and swapping that in clearly results in bad running.   After doing some more reading Im wondering if it might not be the coil pack wiring, it looks a bit knackered, cant see any exposed wires but that doesnt mean much.      I'll look into splicing on replacements as i wont be able to trace the whole lot back and remove, but i can solder ok so worth a try.    

[YellowCar]

Definitely worth a look if coil packs are ruled out, the wiring can get a bit brittle.

[Qubit]

Well ive pulled back more of the wrapping on the wires, i was previously investigating in poor light, to be honest on closer inspection i can't find any of the insulation broken so im guessing thats out.  Ive also replaced the coolant temp sender, no difference though.   Think im just about out really as even small amounts add up.      One strange thing is that sometimes from cold its fine for a while which is weird.    Could it be the thermostat or really left field  -the secondary air pump is leaking and needs looking at - could this be causing issues, i know it only runs for 90 seconds or so.

[ThomasItis]

Have you changed recently fuel filter? What spark plugs have you put in? How many miles does it have?

[Qubit]

Havent changed the fuel filter.   Put in brk6e plugs.   170k!       Think ill run some injector cleaner through next

[YellowCar]

Could be fuel filter as it's ok on cold start when it's over fueling anyway which will mitigate the problem a little

[ThomasItis]

I'm afraid that your spark plugs are not suitable for your car. Also I would recommend to change the fuel filter and have a measure of the fuel pump's pressure. And definately take the injectors out so they will be cleaned properly at a cleaning machine.

 

Start from these 2-3 easy and cheap things and especially change the spark plugs. NGK BKR7EIX is a fair spark plug.

[Mase-dog]

Seems I'm having similar issues, any update on this?

[petrolbloke]

Seems I'm having similar issues, any update on this?

 

Have you tried the suggestions in this thread and what was the outcome?

 

If you have old plugs or the wrong plugs then they are worth replacing anyway. Likewise if your car has not had the coil pack 'recall' done (or has non-genuine coil packs) then that is another thing to try.