1990 sw20 mr2 having problems

[avinesh]

had full 3" exhust system done on my mr2, car ran amazing on the motorway on my way back home but wen i took the exit it started sounding like a cracked exhaust or something an would only boost at high revs an would also fall back on boost a bit just before 7000rpm from 12 to 10psi, car has 3inch stainless downpipe which had little cracks near the turbo..... could it be the manifold or can a cracked downpipe cause this..... cheerz

[solitaire]

Yeah sounds like the cracks are getting bigger id say... have you checked the exhaust sytem to confirm?

[bluemaumau]

go out to car and look for cracks

[avinesh]

Yeah sounds like the cracks are getting bigger id say... have you checked the exhaust sytem to confirm?

i took the heat shield off an the manifold looks ok but the downpipe has cracks on top but will that cause it to lag soo badly an even loose boost in high revs the blow off isnt as loud as before

[solitaire]

i took the heat shield off an the manifold looks ok but the downpipe has cracks on top but will that cause it to lag soo badly an even loose boost in high revs the blow off isnt as loud as before

Hmm, i guess if its after the turbo then its not a factor (techie guys?). If its got a lot of lag then i would say its a exhaust manifold leak or your bov/wastegate/whatever has a problem....

Im sure sergei/fivebob/vvega etc will step in with the answer any sec

[avinesh]

it was over boostin on the motorway it hit 15 two times soo i put the boost down to 12psi an it pulled really well but all of a sudden it started sounding like a broken exhaust an didnt have any low end....

[solitaire]

it was over boostin on the motorway it hit 15 two times soo i put the boost down to 12psi an it pulled really well but all of a sudden it started sounding like a broken exhaust an didnt have any low end....

Ouch... what is your boost controller set to? is your fuel cut still disabled?

I might leave this to the techies... anything else i say with be wild guessing...

[avinesh]

it was over boostin on the motorway it hit 15 two times soo i put the boost down to 12psi an it pulled really well but all of a sudden it started sounding like a broken exhaust an didnt have any low end....

Ouch... what is your boost controller set to? is your fuel cut still disabled?

I might leave this to the techies... anything else i say with be wild guessing...

yea fuel cut is disabled...boost is now set to 12psi

[Adamal]

Cracks in the downpipe wouldn't cause it to this degree. Its after the turbo.
If the manifold was cracked, it would cause problems.

Sounds like actuator problem or a leak in vacuum hoses.

[avinesh]

Cracks in the downpipe wouldn't cause it to this degree. Its after the turbo.
If the manifold was cracked, it would cause problems.

Sounds like actuator problem or a leak in vacuum hoses.

it started doin this as soon as the broken exhaust sound came along....would waste gate actuator make broken exhaust sound.....

[Adamal]

Would parts that bolt on AFTER the turbo cause the turbo not to spool?

[avinesh]

Would parts that bolt on AFTER the turbo cause the turbo not to spool?

may be, some thing like this happened wen my brother took off his subarus down pipe an also i heard from a lot of people when they upgrade thier exhust thier car looses a bit of low end....but mine was ok until the sound came along....and it does spool but late

[Adamal]

Yea, which is why I suggested that it sounds like the actuator is faulty or you've got a leak in your vacuum hoses.
Sounds like the waste gate isn't closing properly when it should be due to either the diaphram in the actuator being broken or the vacuum hoses having a hole or being perished, meaning they can't provide enough vacuum for the actuator to close the waste gate.
When you get higher in the rev range, it provides enough vacuum to overcome the leak.

[bluemaumau]

i cant remember which turbos but dont some routinely snap actuator shaft thingies?

you probley already checked that tho, im not sure on your exact manifold/turbo/WG setup but maybe the welding could have melted a pipe.

basically what adamal said ,lol

[avinesh]

Yea, which is why I suggested that it sounds like the actuator is faulty or you've got a leak in your vacuum hoses.
Sounds like the waste gate isn't closing properly when it should be due to either the diaphram in the actuator being broken or the vacuum hoses having a hole or being perished, meaning they can't provide enough vacuum for the actuator to close the waste gate.
When you get higher in the rev range, it provides enough vacuum to overcome the leak.

ok, but what about the broken exhaust sound it came with the problem is it just a coincidence coz its very noticeable.....

[solitaire]

ok, so, this problem started occuring all of a sudden right? So what was the last thing you changed before this happened? In order for you exhaust's design to be a problem you would have to notice this problem as soon as you changed your exhaust... so it has to be a fault somewhere...

[avinesh]

ok, so, this problem started occuring all of a sudden right? So what was the last thing you changed before this happened? In order for you exhaust's design to be a problem you would have to notice this problem as soon as you changed your exhaust... so it has to be a fault somewhere...

it started doin this wen i got near my house, i heard the cracked exhaust sound first an then the car became slow it started sounding like a lawn mower a lil bit.....

[Chickenman]

dropped a piston?

Maybe the exhaust turbine has had a little bit of something happen to it or as everyone else said there's a hole in your manifold (watch out for your floor.. it may fall out) or there's a problem with actuation and the wastegate is staying open.

Could be HT leads or distributor... lots of things can make a 3s sound like a tractor. My old one started sounding like a tractor when something smacked the end of number 3 spark plug and it ceased it's sparking.

Take it to a mechanic.. you know, a real life one, everyone else is going to be guessing.

[avinesh]

dropped a piston?

Maybe the exhaust turbine has had a little bit of something happen to it or as everyone else said there's a hole in your manifold (watch out for your floor.. it may fall out) or there's a problem with actuation and the wastegate is staying open.

Could be HT leads or distributor... lots of things can make a 3s sound like a tractor. My old one started sounding like a tractor when something smacked the end of number 3 spark plug and it ceased it's sparking.

Take it to a mechanic.. you know, a real life one, everyone else is going to be guessing.

its exhust related its not the engine.....it idles properly an sounds normal its only when you rev it.....it revs out smoothly as well only doesnt have the mid range punch any more an it still boost 12 psi only later in the rev range, everythings normal it drives well starts normal only sounds like it has a cracked exhust when reved, and reaches its boost level but later in the rev range.....

[solitaire]

(watch out for your floor.. it may fall out)

stay out of china town or Johnny Tran will tourch your ride

its exhust related its not the engine

Take it into toyota then mate, have you check your diagnostic codes?