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JDM 93 wrx jerky boost

3K views 5 replies 4 participants last post by  Speed Stick 
#1 ·
Hi, I just picked up myself a 1993 WRX (GC8) imported from Japan. Runs really good (except high rpm boost obviously). Just needs new belts and has a jerky boost issue. I searched but couldn't find anything besides possible fuel not being high enough octane(got 92 in it) and possible boost leak is what I was thinking.

When the car is under full boost and at about 5k rpm and up the car becomes all jerky. Jerky is the best word I can think of. Like the boost comes and goes real fast above that RPM. Doesn't matter what gear the car is in. The clutch is good I am pretty sure. Doesn't slip and doesn't smell. The turbo pulls really strong still up to that time.

Sorry, never owned a Subaru. Have a 2000 Honda Prelude and just sold my 1991 GT-FOUR RC. Help would be greatly appreciated, thx in advance.
 
#2 ·
Problem diagnosis would be a better part of the forum for this post. Not sure about canadian customs. But, in america. The exhaust would've had to be more than likely re-done to american emissions. Thus, something else could've been tampered with or it would probably bottle neck the current set-up on the ECU. Your going to have very limited help on these boards. Because most of us are not familar with JDM Wrxs. Not sure if NASIOC is any better on older models or not. But, give it a try. They have a pre 2002 turbo factory section. Pre-2002 Factory Turbo Powertrain - NASIOC Just know they're not the easiest bunch of people to get along with other there.
 
#4 ·
I managed to get answers from Western Subaru Club canada. I guess a couple other guys with the JDM wrx's had the same problem and it is the ignition coils/coil packs. And here in Alberta we don't have emissions so I'm lucky.

I'm actually pretty sure its not an overboost since the gauge doesn't go down.
 
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