Timing chain changed now car backfires! =(

[hayche]

Hello Everybody.

Hopefully some of you good people could shed some light on a problem we now have with our 2016 1.2 dig T (37K). Basically the chain started rattling because I let the oil get too low, hard lesson learnt!. Now upon having the timing chain replaced it has developed a popping sound on deceleration at around 2500/3000 rpm, confirmed backfire from the exhaust using tissue at the tail pipe, if I go beyond to around 4000 rpm is does not pop!. This is happening when the car is stationary whilst just revving and whilst driving. There also seems to be a very slight vibration whilst holding the revs at 3000 rpm, kind of like a weak electric shaver. The mechanics took a quick look and said it could be a sticking valve which is more expense! =(

I have uploaded it to YouTube below, I guess my biggest worry is that the timing could be slightly off. I would think that a sticking valve would be present on more than just releasing the accelerator but i really have no clue!. The car does idle perfect to my untrained ears.



Thanks
Howard

[MikeGC]

hayche

Welcome to the forum.
Sorry I can’t help

[hayche]

Thank you Mike, no problem at all I realise this is a tricky one.

Cheers
Howard

[andy2019]

Take it back to who fitted the new chain and get them to check it over

[hayche]

Thanks Andy, yes definitely a good call which I am working up too, I am trying to gather as much knowledge as possible because I know how much work it is just to check the timing, they will probably be reluctant to do it, especially if it is a sticky valve and they know the timing was done correctly. From what I am reading the 3000 rpm vibration could be from the balance shaft being off.

Cheers
Howard