1996 Legacy GT TT high rpm sputtering

[96wagonzilla]

I went to the mountains the other night to do some "driving" and noticed that when I nail it, once the tach reaches around 6000 the car starts to sputter violently. What are some possible causes of this? It only does this at high rpms. It is a Japanese spec GT, there isnt a rev limiter or anything like that. I am wondering if maybe the fuel pump may be going out, but wouldnt it sputter more often if that was the case?

[Huffer]

Actually there is a rev limiter, unless you've got something installed to bypass that.

There is also a fuel cut limit on some models also.

Other than that, you could be looking a a fuel issue - perhaps a pressure regulation problem, or even a lack of sufficient airflow for combustion.

[Airgne]

cant be the rev limiter. he has a jdm car his rev limit is around 8000rpm's i think. you might had a boost leak, or one of your coils is bad.

[Huffer]

Redline is definitely not 8000rpm.

[subba]

Both my cars RPM max out at 8000 but the redline is
GT - 7500
Non Turbo - 7000

Did you swap the motors yet?

[decke48]

is it wastespark or coil on plug gt spec? does it do this if you rev the car with no load? can you check for fuel pressure? spec. 35-40psi 3000rpm 50-55psi idle with no vaccum to pressure regulator. doesnt really sound like a fuel pump. sounds like a injector or a pressure regulator to me. if the pressure is low at high rpm(pressure should be at around 50-55psi) its a stuck open PR and isnt deleivering the correct fuel mix. anyone good at duty cycles or injector pulse cycles might be able to help fiqure if its a injector.. but i would start with a pressure regulator first

[Airgne]

7500 is alot closer than 6000.

[Reuben]

cant be the rev limiter. he has a jdm car his rev limit is around 8000rpm's i think. you might had a boost leak, or one of your coils is bad.

Only STi's rev to 8k. Red line for a GTB is 7500 (Limiter in mine was about 7750), for a GT i think around 7000.

Anyway, a mate of mine had this on his gen 1 GT, with a V3 STi motor transplant. The issue was sparkplug gaps (something i know nothing about). So just pointing out missing in the high RPM's can be anything.

[1996Battlewagon]

I'm with Huffer on this, sounds like a fuel problem. If the sputtering is violent enough that the car is bucking, your fuel pump might be on the way out. Just a thought.

[subba]

nice discussion but the car is probably in 10 different countries lol but dont mind me, the info might be usefull to someone else someday