Exhaust\Engine Popping

[DarthMJH]

Hi,

On my 2.4 911T the exhaust \ engine would make a popping sound at low/high revs, I took it to a garage and said the valves needed adjusting, as they were no closing properly. This was done and it ticks over now fine and at low revs it's great, but the popping comes back again at anything over 3300 Revs.

Any ideas what this could be, could it be a sticky valve ?

Many thanks

Mike

[Jules Dielen]

Did you have them check for exhaust leaks? Even the tiniest one has strange consequences.

[DarthMJH]

Ah now you come to mention it, they did mention a slight hole in the exhaust, I will have to check to see if they welded it.

Also I think it has the wrong heat exchangers as there is a pipe on the left hand side that is meant to go to the injectors I believe, but mine is a carb model so it there is no long pipe on it to the engine. Do you think that could cause an issue ?

[M_deJong]

Is it a US 2.4T that was originally MFI or a ROW 2.4T that was always carbureted? Which carbs does it have? Does it pop under acceleration, steady state, decel?

[DarthMJH]

Its a Euro 2.4T that has always been a carb model. I think someone just fitted the wrong heat exhanger before I had it. If the car is parked and I just push the pedal to 3300 rpm or above in a steady state it does it then. It also happens when coming off the gas as well, but not as frequently.

[M_deJong]

The heat exchanger fitting doesn't matter.
High RPM at standstill... don't do that, but it seems to be a little lean. Coming off the gas closed throttle a little popping could be ok. Overall it seems the car is running lean. An exhaust leak would cause this (or an intake leak). But so does modern gasoline. I would have someone good adjust and maybe rejet the carbs to compensate for "modern" gasoline.

[DarthMJH]

Thanks all for the advise. I will take a look at the exhaust and get someone to look at the jets.