I have a boost gauge and it usually peaks at 9lbs and holds at 7lbs. Now it goes all the way up to 15-20lbs and once it gets to 10lbs or higher it bucks really bad. I might as well jump out of the windshield! I changed the spark plugs and 2 were blown. That didn't help. Any place I ask no one knows. It isn't throwing any codes either. All the vaccum lines were checked and they are fine. Someone said maybe fuel filter needs changed. I did research on it and it isn't serviceable. What else could it be???
HELP! Why is it bucking?
- Thread starter speedette
- Start date
Newf said:your problem has to be completely different I'm figuring. But a lot of MSP's bucked, even mine, before we had the ecu flashed. Mine is stock, always has been.
But, no worries, if your hitting 15-20 psi, she won't buck for much longer...soon it'll all be over
Thanx for the heads up cause it makes me so mad I do it on pupose now.
Well, the stock turbo is only efficient to around 1bar. I can't imagine a completely stock MSP spiking to 20psi for long without blowing up. Could be a faulty boost gauge along with something else because an OEM-equipped MSP shouldn't be boosting to 9psi anyway..
So why won't the dealer fix it?
So why won't the dealer fix it?
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- 2003 Subaru WRX Wagon, 2000 Miata
it might be a faulty wastegate, it's not opening enough and is letting the turbo build too much boost. the bucking is from fuel cut.... i would get your car checked out asap. just don't go into full boost.
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- '13 CWP MS3 & '16 Mazda6 GT
yeah, sounds like your wastegate acutator is gone...
shane02pro5
25ish_psi
- :
- New Caney TX
Definately sounds like a wastegate issue. I have read many instances where this has happened.
Don't even let it get into boost!! New motor will be much more of an inconvenience.
Don't even let it get into boost!! New motor will be much more of an inconvenience.
TX Speed Demon
Member
Having the wastegate stuck open is a common problem, but that would mean you could build very little or no boost. Having the it stuck closed (so boost continues to build) is not a very common problem.
First just replace your wastegate vacume lines. If the line to the wastegate is broken it won't ever open and your boost will just go up and up.
The stock lines get really brittle over time and easily crack. Some common places for it to break:
- T fitting that leads off to stock BPV - the T fitting is plastic and cracks easily.
- 90 degree fitting at wastegate connection (where line attaches to wastegate)
- 90 degree fitting where it starts at the intake manifold.
- Line itself can dry out close to the turbo/wastegate. When changing a friend's intake I touched his and it split in hlaf in my hand.
Definately change all the vacume lines leading to the wastegate (1 line but split into 2 parts)
First just replace your wastegate vacume lines. If the line to the wastegate is broken it won't ever open and your boost will just go up and up.
The stock lines get really brittle over time and easily crack. Some common places for it to break:
- T fitting that leads off to stock BPV - the T fitting is plastic and cracks easily.
- 90 degree fitting at wastegate connection (where line attaches to wastegate)
- 90 degree fitting where it starts at the intake manifold.
- Line itself can dry out close to the turbo/wastegate. When changing a friend's intake I touched his and it split in hlaf in my hand.
Definately change all the vacume lines leading to the wastegate (1 line but split into 2 parts)
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