car is banging when i come of trottle any ideas

banging or knocking??? as this could very well be related to your lack of boost.

Check spark plugs coil pack plugs etc

banging , but it runs too smooth at idle to be timing , i have new plugs

Id do the ecu check asap and see what it highlights

cheers i will

i get this to after coming off the accelerator lots of popping from the exhaust was worse before i fixed the air filter today, not long back from a test run in it, it still pops just not as much car is also running in safety boost 7psi

so what is the problem , mine is dido sounds class though , :tank:

banging , but it runs too smooth at idle to be timing , i have new plugs

 

did it missfire before you fitted new plugs?

dont know as i bought it with the bearings gone , the plugs fitted are ngk the exact ones for the car platinum

:rockon:

NGK PFR6B-11C for TT:)

its fine just unburnt fuel burning in the turbos.

 

do you have dump valves by chance.

banging from the exhaust etc is caused by Over-fuelling! your fuel map is wa*k which will point to your 02 sensors being gash, thus your air-fuel ratio is shit, back to stock routine as it cant measure the afr and your naturally over-fuelling as its safer for the engine than running lean especially on boost!

banging from the exhaust etc is caused by Over-fuelling! your fuel map is wa*k which will point to your 02 sensors being gash, thus your air-fuel ratio is shit, back to stock routine as it cant measure the afr and your naturally over-fuelling as its safer for the engine than running lean especially on boost!

 

Very rare for overfueling to cause a backfire through the exhaust, it normally chucks out black smoke which is very evident on tickover. It sounds more like perhaps an exhaust valve leaking or a timing issue. If you are very sure that the timing is OK, I would be inclined to do a Conzult power check or a compression check. This would highlight a cylinder with a problem.

Sounds like it could be a boost leak to me...

whats the best way to check for a boost leak?

In Blue Peter style........Hers one i made earlier

http://www.300zx.co.uk/forums/showthread.php?t=115751&highlight=diy+boost+leak

whats the best way to check for a boost leak?

 

You will need a boost leak detector - do a search, there should be loads of threads on it

car is banging when i come of trottle any ideas

 

There is more than one possible cause for this, however given what you have been doing to the engine its a fair bet an air leak been drawn in upsetting the mixture just as you come off the throttle, running rich when off the loud pedal completely like say down hill is not possible as the injectors switch off in this mode, like most fuel injection systems as the ecu see`s a closed throttle switch and high revs at the same time.

 

An air leak in the exhaust can also cause this but to a lesser degree, there is always a small amount of fuel in the exhaust as no engine can burn 100% of the fuel any air introduced to the exhaust will then add to the unburnt fuel and the hot exhaust so hence popping.

 

You need to go back to basics, start from the air flow meter and work through all visable jubille clips etc, that are holding air and turbo pipes in place.

 

You will as some time require a boost leak test as mentioned by others, a simple way of slightly pressurising the intake and turbo ducts to show up any leaks, these leaks draw air in on overrun and loose boost when you put your foot down, seems the most likely answer to the problem.

 

Happy holidays

 

Jeff TT

Edited December 13, 200916 yr by JeffTT
flipping spellings!!

You will as some time require a boost leak test as mentioned by others, a simple way of slightly pressurising the intake and turbo ducts to show up any leaks, these leaks draw air in on overrun and loose boost when you put your foot down, seems the most likely answer to the problem.

 

Jeff TT

 

Blimey - I actually offered some helpful advice !!! :biggrin: It's only taken me 5 years !!

Blimey - I actually offered some helpful advice !!! :biggrin: It's only taken me 5 years !!

 

 

Keep up the good work !!!

 

Jeff

Blimey - I actually offered some helpful advice !!! :biggrin: It's only taken me 5 years !!

 

You go mate, gold star for you, cant wait for next one in 2014...

You go mate, gold star for you, cant wait for next one in 2014...

 

Cheeky Git !! I will only impart my wisdom on something that I have experienced before - don't want to hand out any duff advice !!

thanks lads i have new rings so i dont think its compression , it starts first turn of the key so i dont think its valve timing , how could i check ignition timing , best thing to do would be to get another car and just check all is the same :oops:

hey lads i got her plugged in and 02 sensor bank 2 is staying at .36v is this right seems like its stuck other sensor changes voltage :batman:

IIRC it's suppose to adjust like the other so it's probably had it.

o2 sensors wouldnt cause the problem your having.it will be something else.Carry out the checks Jeff mentioned first,You could unplug both o2 sensors and it would not make it backfire.