coil problems on cylinder 4

[markbrum]

hi guys i need your wisdom....02 cupra r 210 ( amk ) coming home from work few weeks ago and car runs rough and judders eml came on so crawled home keeping revs down.. gets car on drive and notice smoke coming from under bonnet just thin smoke if that makes sense.. well i run vagcom and came back with miss fire on cylinder 4 great i thought new coil and jobs a good un..well replaced coil bought from seat stealer and car sits on drive runs great ( in plaster with broke foot ) so car not used for 2 weeks my mates takes car to get washed im passenger all is fine till we get back and then damn starts running rough again no eml nothing..plug vagcom back in same fault so i get another coil and change it again still same fault...do you guys think it could be compression on cylinder 4, bad injector to cylinder 4, or bad wiring to either coil connector to loom or injector wiring im at a loss now apart from broken foot i now got a broken car so any help will be much appreciated

 

[stewbie55]

Spark plug?

 

[markbrum]

sorry did'nt fully explain...i replaced all plugs as well as recommended by seat... well tomorrow im on phone to an auto electrican after reading some posts and doing some searches i think it might be wires to plugs or ecu so gonna get them to check it tomorrow also noticed when car was at normal temp my cat was smouldering think it might have collapsed or its the unburnt fuel from miss fire

 

[chrisphysics]

Try running with the MAF disconnected this will force limp mode and should help you decide weather it's a sensor issue or something more physical.

 

[Damoegan]

check the wiring from the coil pack plug..

 

[DPJ]

I take it you cleared the fault code after you first replaced the coilpack?

 

[markbrum]

guys looks like it all sorted, auto electrican came out this morning stripped car to check all wiring from injectors and coils all the way back to ecu under scuttle but no fault found with wiring.... fault was... confused ecu with miss fires on cylinder 4 no being able to clear fault with new coil in place , so he cleared faults with his diagnostic tool (massive piece of kit ) and it came back as miss fire on cylinder 2..replaced all coils and running like a dream again. so if anyones needs a damn good auto electrican there name is, Auto Electric Solutions. tel no. 0121-684-0734 mobile no.07966184636, great service and value for money very nice bloke aswell... but thankyou for all your suggestions..

 

[slim20vt]

wires to injectors and coils check for splits and shorting out the harderd u drive the lcr the worse it will get!! i had same problem.. to a thread search for cylinder 3 down again!! this thread was about my lcr bam ,got to the bottom of it explains all hope this helps........

cheers