Monday, October 22, 2007 - 10:52 pm, by: Danny Minns(Poju89)
Ok i tried a search and couldn't find anything i'm looking for.
problem is i get a backfire when i change gears, its rather loud and getting annoying.
i only got the car last week, the fella i got it from said he removed the cat when he first got it and it made the noise ever since, but it has a full new exhaust on the car. Its a TT manual from the factory i'm pretty sure, i can check the plate if some one can tell me what all the letter codes mean.
any help is welcome
Brian Timms DieHard New South Wales TT Soarer Goodness.
Tuesday, October 23, 2007 - 07:12 am, by: Brian Timms(Turbo_brian)
1JZ's have this really funky feature built into the ECU which is the cause of the problem, mine does it to, and you mainly only get it with cannon or large diameter mufflers.
What happens is the engine builds up power as you accelerate, and when it comes time for the auto to change gears, you get something like the following happen:
Auto: Hey ECU, I wanna change gears! ECU: Sure Auto, give me half a nanosecond to sort my crap ECU: Engine, Auto wants to change gears! Engine: Sure ECU, wadda ya want me to do? ECU: Retard your timing a bit hey Engine: Why? ECU Cause you got to much torque and power, Auto is soft and might get hurt Engine: Sure, retarding timing! Engine: Done ECU ECU: Cool, Auto, you hear that? Auto: Yeah, thanks, changing now! Exhaust: Burble/farting noise! Auto: Ok, changed gears ECU: Thanks Auto, hey engine, re-advance your timing Engine: thanks ECU, advancing timing
And this is all done within a second or so, but the engine retards it's timing briefly to remove the huge amount of power being delivered to the gearbox in order for a smoother safer change of gears.
Best way to fix this is a shift kit from MV Auto's in SA.
B.
P.S. I am still drunk from last night if you didn't guess it from the post :p
Tuesday, October 23, 2007 - 05:55 pm, by: Danny Minns(Poju89)
yeah its a manual but good try
could it still be the timing just when i jump off the accelerator same kind of thing happens?
the fella said that its done it ever since he removed the cat and now it has a complete exhaust system on it. maybe the new mufflers are sending it weird.
Brian Timms DieHard New South Wales TT Soarer Goodness.
Tuesday, October 23, 2007 - 10:30 pm, by: Brian Timms(Turbo_brian)
Nah, doesn't sound like a factory manual (and yeah, was rather drunk from last night, it was yr 12 formal, and lucky me managed to find himself in the afterparties in the townsville casino, so got merily plastered).
If it's got ECU engine retarding, it has an auto ecu (easy to check, pull the passenger carpet back, remove the kickboard cover and see what the ECU sticker says.
Wednesday, October 24, 2007 - 06:25 am, by: Matthew Sharpe(Madmatt)
Most likely cause is overly rich mixture. Cats do require a slightly rich mixture to run properly so it could just be that having the cat out is allowing enough fuel through.
Ignition timing is a possibility also.
Another possibility is poor ignition not fully burning the available fuel.
Its probably a mix of several things causing it.
Whatever is causing it, too much unburnt fuel is reaching the end of the exhaust and igniting when it hits the open air.
Wednesday, October 24, 2007 - 06:12 pm, by: Danny Minns(Poju89)
yeah it has FMIC, 3inch (i believe) system, pod filter and there is no auto ecu.... has a linkplus in the glovebox. also has hi-flow steelwheel turbos.
the car has been tuned on a dyno •• and had something along the lines of a back off when changing gears and what not.
Sunday, April 15, 2012 - 07:37 am, by: Enzo Seidl(Enzoisamazing)
LOL brian, nice explination for the gear retarding xD.
Mate, it wouldn't happen to just be the way your shifting would it? Sounds strangly similar to what my mate experiences when he puts his foot on the accelerator before the clutch is fully disengaged, and it gives off a pop/bang/ possible flame depending on if the exhaust is real hot.
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