Mis-firing Fiesta

[conny]

Got a Y reg Fiesta (2001) which is mis firing. Had the plugs, leads and coil changed with no effect. Noticed recently that No 2 lead cylinder the plug has oily deposits on it. Someone has suggested putting something called 'seal conditioner' in the oil and also using a thicker grade oil. Will this help and what grade should I use.
Thanks.

 

[markthemechanic]

Could be 1 of 3 reasons. 1 Oil contol rings and compession rings on pistons broke or worn. A compession test would confirm this. 2. Valvestem seals have come off or worn, if car smokes when first started this would indicate that this is the problem. 3. Cylinder head gasket has blown between compession ring and oil chamber. You can sometimes check this out by removing dipstick whilst car is running and put your thumb over the hole to see if there is any kind of pressure there, this may not be accurate test as cracked or worn oil control rings and compression rings can show similar symptoms.

 

[conny]

Thanks Mark.
Will arrange to try and get these tests done.

 

[markthemechanic]

ok, let me know how you get on.

 

[conny]

Hi Mark,
not had a compression test done yet. Mate tried the dipstick test and said it seems fine, slight pressure when he blocked the hole. have bought a bottle of 'Leak Stop'. in the hope this will help to soften the seals so will run this in and give the plugs a good clean and re-gap. Hopefully it may work, if not then I will get the compression check done. How much will a garage charge for this? have you any idea.
cheers mate.

 

[Stivino]

What model of Fiesta is it, engine etc? Take it to a garage and get them to diagnose and quote for the repair. If you must check the compressions, get a tester and do it yourself.
http://www.drapertools.com/b2c/b2citmdsp.pgm?pp_skmno=37442

http://www.amazon.co.uk/Draper-3744..._1_1?ie=UTF8&s=diytools&qid=1216158751&sr=8-1

 

[markthemechanic]

as a mobile mechanic i can only tell you what i would charge and that is £20. i would waiver the cost of the test if you wished me to carry out any repairs needed.