Do you know if the new tb was in good nick? Did you give it a going over before you put it on? Just a thought...

usually popping and backfiring is caused by an exhaust leak.. when you back off the throttle, air is sucked in the hole and allows any unburnt fuel in the exhaust to burn because it is an air/fuel mix again.. it gets worse when the engine is hot because the heat from the pipe ignites the mixture more easily..

yep, thats exactly my thought last night when i was reading the posts above, i still haven't had time to check tho, i think its prolly a head/mani leak

Thats most likely my problem too... just had a good look at my exhaust manifold and it has a big crack in the number 4 runner... the popping has gottn worse after my engine swap, probably because the crack has opened up a bit more.

 

Time for some extractors me thinks...

Problem as I understand it is when the engine gets properly warm there is a bit of misfire at low throttle, but when floored it clears. It also has an exhaust pop after heavy throttle back off and the mixture is a bit rich.

 

Although it sounds like a electrical sensor or ecu malfunction it is more likely to be the injectors are dripping into the cylinders, it happens more when the engine bay is hot. When on the freeway or travelling at speed the airflow disapates the heat and so the problem is less evident but in traffic esp stop and go the heat builds up and makes the problem much worse.

 

The dripping causes the chambers to flood to a point where the plug can't create the necessary boom, it doesn't happen every cycle which explains why its not timing or tuning (given the std ecu does give you flexibility in fuel delivery it can't be that either). It misses at part throttle because it has no air, and therefore can't combust whereas at full throttle there is sufficent air.

 

If you drive lots of short distances or a large proportion of long distances you can find the problem is barely noticeable and when you send it to the garage they fix something and viola you think thats gone too.

 

Get your injectors serviced ie stripped and reset up with new seals etc with anything else do one thing at a time so you know what solves the problem !

have u tried a new set of plugs?

jeez, i totally forgot about this thread...

 

i got an emanage put on and tuned and as part of the tuning the timing was advanced and it pops more now, i've swapped a recon'd head on and done a heap of other stuff and i'm just accepting now that its cos of the exhaust flowing better and allowing the sound to carry through the system. same thing happens to almost every car i know that's had a bigger exhaust put on

jeez, i totally forgot about this thread...

 

i got an emanage put on and tuned and as part of the tuning the timing was advanced and it pops more now, i've swapped a recon'd head on and done a heap of other stuff and i'm just accepting now that its cos of the exhaust flowing better and allowing the sound to carry through the system. same thing happens to almost every car i know that's had a bigger exhaust put on

 

 

uh oh, I'm getting a 4" cannon put on my ae82 this friday lol... oh well it can't sound as bad as my muffler that is torn in half ( dam i wish i didnt take the dizzy of that day)