Issues with evo 8. Driving me insane. Please help :(
if the wastegate flapper seals properly and the wastegate properly loaded i would suggest testing the wastegate by connecting the boost source directly to the wastegate. this should give you a steady wastegate boost accross the board(about 11-14psi). If this is good then i would check your mbc and afr. if you know what afr you are running during the pulls that will help us diagnose the issue.
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From: in a garage
You shouldn't even be driving it.
WG flappers are checked with an air compressor at low pressure, slowly increasing pressure until the flap starts to move, then note the pressure on a gauge.
WG flappers are checked with an air compressor at low pressure, slowly increasing pressure until the flap starts to move, then note the pressure on a gauge.
Try capping both hoses that go to the gfb bov and take off the gfb bov. Ya you will get alot of compressor surge between shifts but it wont hurt anything assuming its not left that way. Make sure whatever is used to plug or cap the hoses will not get sucked into the intake pipe or blown out of the charge pipe.
Try capping both hoses that go to the gfb bov and take off the gfb bov. Ya you will get alot of compressor surge between shifts but it wont hurt anything assuming its not left that way. Make sure whatever is used to plug or cap the hoses will not get sucked into the intake pipe or blown out of the charge pipe.
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Joined: May 2017
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From: Gold coast.
Really appreciate the help guys. I bought the car with this issue although it wasn't as severe as it is now.
I am going to track down a stock intake pipe and Airbox. Also I need to find a mechanic that will do the following tests you guys mentioned
I will also take a video of the car running tomorrow. It idle most of the time although the car almost stalls when stopping at traffic lights or the revs drop really low sporadically.
I am going to track down a stock intake pipe and Airbox. Also I need to find a mechanic that will do the following tests you guys mentioned
I will also take a video of the car running tomorrow. It idle most of the time although the car almost stalls when stopping at traffic lights or the revs drop really low sporadically.
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From: Gold coast.
Another thing to note guys.
I have tried disconnecting the mbc and running Wastegate pressure. I have 18 psi spring.
the car struggles to hit 15 psi then boost falls off a cliff to about 10 psi before spiking back up to 19 psi by redline.
I have tried disconnecting the mbc and running Wastegate pressure. I have 18 psi spring.
the car struggles to hit 15 psi then boost falls off a cliff to about 10 psi before spiking back up to 19 psi by redline.
Sounds like a bad bov to me. Some people say you will blow up a turbo immediatly with no bov and other people actually run cars like that for years without problems. Its your call, maybe you have a different bov to try that doesnt cost you anything and thats less risky but personally i have driven my own cars like that before and my turbos never blew into pieces even my 2jz stock twin turbos at 19psi with ceramic exhaust wheels survived.
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From: Gold coast.
Sounds like a bad bov to me. Some people say you will blow up a turbo immediatly with no bov and other people actually run cars like that for years without problems. Its your call, maybe you have a different bov to try that doesnt cost you anything and thats less risky but personally i have driven my own cars like that before and my turbos never blew into pieces even my 2jz stock twin turbos at 19psi with ceramic exhaust wheels survived.
Also if I drive with light throttle for 5 min it seems like the car responds better. As soon as I do a couple of full throttle pulls the turbo starts spooling really loud, as if its working really hard to make boost, and the exhaust sound will constantly change. Sometimes it sounds raspy and rattly, other times it sounds like its choking. If I apply gradual throttle the exhaust starts to sound better and turbo seems to respond better. But still not at the level the car should be at.
Also wanted to ask. Is it possible for the boost gauge to leak? Should I try disconnecting the boost gauge?
Last edited by Addex; Sep 7, 2017 at 06:35 PM.
Sometimes a boost gaige will leak but not enough for your car to not build boost proper. Could be a bad turbo. Have you checked for shaft play? Have you tried moveing the wastgate actuator arm to see if its moving correctly and not binding? Spin your turbo compressor wheel by hand to see if it feels smooth and doesnt have tough spots. Do you have a wideband? What afrs in boost? What afrs cruising? Afrs idle?
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From: Singapore
Since you said that you bought the car and it has been acting weird. I am starting to believe that the previous owner could possibly have de-kitted some parts without having to do a retune(of course, he is selling the car). You may want to pull the logs and maps for us to take a look at well.
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From: Gold coast.
Hey guys. I did another smoke test and it's leaking from the bottom of the blow off valve where it connects to the air intake. I have tightened the clamp as hard as I could go and it's still leaking! Am I going insane?? I thought it was the blow off valve leaking but it's where the hose clamp is connected to the air intake. I have tried several clamps and smoke is still pouring out.
am I supposed to be using specific clamps?
I'll be posting fuel trims and video's tomorrow for you guys.
am I supposed to be using specific clamps?
I'll be posting fuel trims and video's tomorrow for you guys.
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Joined: May 2017
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From: san jose
Hi guys
its been 4 months now and I cannot for the life of me find issues with my evo 8. The car has been to countless mechanics and they have no idea. You guys are my last hope.
Issues with the car listed below
- Exhaust sound weak and strained/restricted from 3000rpm and above. Usually it screams and sounds awesome when coming onto boost. That sound is now long gone.
- reaching full boost at 4500rpm
- Incredibly slow spool
- Backfiring after boosting
- struggling to reach 15psi, will drop off to 12 psi then shoot back up to 17psi by redline.
- Other times it will spike to 18 psi.
- Rich smell from exhaust
- extremely Poor fuel economy
- Poor boost response
- Car feels like its hesitating on fast gear changes. Like it will hold back at 15 psi and struggle to hit 16 psi.
- Engine sounds rough at times.
- Car feels better if I gradually apply very light throttle.
Things I have tried listed below
- Found the EGR leaking. I have removed EGR completely. Blocked off all necessary plugs.
- GFB plump back bov leaking from flange. Although I have tried to install the bov backwards for 1 lap around the block to see if it holds boost better but issue still remains.
- Replaced cat with high flow cat.
- Replaced intake pipe
- Changed spark plugs
- Changed to jdm coil packs
- Have taken the car to exhaust place to see if I had an exhaust leak but cant seem to find a leak
Mods done to car
- Plazmaman intake pipe
- Pod filter
- Mbc
- Turbosmart wastgate actuator
- JDM coil packs
- High flow cat
- Ralliart muffler.
Please guys. Any help would be greatly appreciated.
its been 4 months now and I cannot for the life of me find issues with my evo 8. The car has been to countless mechanics and they have no idea. You guys are my last hope.
Issues with the car listed below
- Exhaust sound weak and strained/restricted from 3000rpm and above. Usually it screams and sounds awesome when coming onto boost. That sound is now long gone.
- reaching full boost at 4500rpm
- Incredibly slow spool
- Backfiring after boosting
- struggling to reach 15psi, will drop off to 12 psi then shoot back up to 17psi by redline.
- Other times it will spike to 18 psi.
- Rich smell from exhaust
- extremely Poor fuel economy
- Poor boost response
- Car feels like its hesitating on fast gear changes. Like it will hold back at 15 psi and struggle to hit 16 psi.
- Engine sounds rough at times.
- Car feels better if I gradually apply very light throttle.
Things I have tried listed below
- Found the EGR leaking. I have removed EGR completely. Blocked off all necessary plugs.
- GFB plump back bov leaking from flange. Although I have tried to install the bov backwards for 1 lap around the block to see if it holds boost better but issue still remains.
- Replaced cat with high flow cat.
- Replaced intake pipe
- Changed spark plugs
- Changed to jdm coil packs
- Have taken the car to exhaust place to see if I had an exhaust leak but cant seem to find a leak
Mods done to car
- Plazmaman intake pipe
- Pod filter
- Mbc
- Turbosmart wastgate actuator
- JDM coil packs
- High flow cat
- Ralliart muffler.
Please guys. Any help would be greatly appreciated.