Cause popping/back firing from the exhaust?

Popping/back firing is normally unburnt fuel I think, therefore a rich mixture?

SkinzCinqSporting said:

Popping/back firing is normally unburnt fuel I think, therefore a rich mixture?

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:yeahthat:

Thats what I thought... but I took my car to some place today cause I got a popping from exhaust when I do the following;

Accelerate in 2nd Gear to near top then brake for road hump.

I get a pop sound which is def from the exhaust back box but I was told that it is most likely my K&N causing the problem and that I should put my standard box back in to test but I can't test the normal box as some of the piping has broken so it will leak anyway.

What you think?

An induction kit will make your engine run a little on the lean side check your spark plugs to see if they are dirty or have a white diposit on them black= rich and white =lean

I just had a service and the guy said the sparks were fine, they be plantinum tipped and the leads be the 15mm performance leads... I will check again and take a photo and show you.

Trancendental said:

I just had a service and the guy said the sparks were fine, they be plantinum tipped and the leads be the 15mm performance leads... I will check again and take a photo and show you.

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Yes your plugs may be OK mate but the dirty or white deposits give you an indication of how the carb is tuned Black = rich and white= to lean could be just the case of tuning your carb to get the fuel to air ratio correct

PNL said:

Yes your plugs may be OK mate but the dirty or white deposits give you an indication of how the carb is tuned Black = rich and white= to lean could be just the case of tuning your carb to get the fuel to air ratio correct

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Nice one... I think I'll have it checked by the pro tomorrow and then have the emmisions checked on an emmissions analyser, tis usually how the garage tunes my car but I let someone I thought was a pro do it by looking into the combustion chamber and making sure the flame was blue.

mate, yeah, popping and banging can be caused by it running to lean!

Dunc

Trancendental said:

Nice one... I think I'll have it checked by the pro tomorrow and then have the emmisions checked on an emmissions analyser, tis usually how the garage tunes my car but I let someone I thought was a pro do it by looking into the combustion chamber and making sure the flame was blue.

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Idealy your spark plugs should be showing a light brown deposit then you are running on the right fuel to air ratio but if you have and induction kit fitted then they will have to compensate as the induction is giving you a lot more air so good luck and hope you get it sorted befor someone thinks your trying to hold up a bank BANG

Is def running lean.

No adjustment can be made to compensate unless I increase the size of the Jets in the Carb OR reduce the size of the induction kit.

Am I running rich? as I keep popping and so on. I've had beans for tea.

lot of cars willpopw along if there is even a very mild vacuum leak.
got my volvo to backfire spectaculary with a bad vaccum leak!

Trancendental said:

Is def running lean.

No adjustment can be made to compensate unless I increase the size of the Jets in the Carb OR reduce the size of the induction kit.

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Ok then if its running very lean then you have to do some thing as it can cause promlems such as over heating and burnt out Exhaust valves I take it you have had the mixture checked to know that the car is running with a lean mixture and the plugs are showing very white deposits Induction kits will weaken the mixture as they are taking in extra air.

Could be that the timing is out too. Does the engine rev ok? Did the garage definitely set it properly?

I suspect the engine is running lean. Check for air leaks on the induction side, and if those are ok then it could be that your air filter is flowing too much air hence weakening the mixture.

Do as the others suggested and check the condition of the plugs as this will give a fairly good indication of lean or rich.