my friend has a 98 gst and he bought a brand new bov. its a knock off of the type s. anyway when he accelerates at around 5000 rpm the motor seems to cut off fuel. its like when a top speed governor kicks in. he took it out and put the stock bov back in and the problem stopped. anyone ever hear of this problem or have any suggestions on if it can be fixed or what to do?

 

Could be popping open which would cause a big problem with unmetered air. Does it do this on part throttle only, right on the edge of boost/vac?

 

LMAO
$10 says he's actually hitting fuel cut.

The reason I say this is because he has a 2nd gen DSM. These cars came equipped with a plastic BOV thats prone to leaking at any boost level above 12. If he set his boost controller with the stock BOV, he is definately going to have to re-set it with this new BOV.

-EngineBuilder

 

if the car is using a manual boost controller make sure it's plugged up the right way because if you have the wrong side going to the wastegate you're going to hit boost cut way before you should.

-brandon

EDIT: Since when you change it back the problem goes away it def. could be that the bov is coming open.

enginebuilder what the hell are you talking about, if he has it set at say 12psi with the stock bov and changes over to a different one that is capable of handling more boost without leaking why would he need to reset the boost? I think i'm misunderstanding what you're saying.

This place needs Ian back.

 

I'll be nice, since I'm new to this forum, and you don't know me yet. Suffice it to say that I have ALOT of experience with DSM's, and I really do know what I'm talking about.. (state certified mechanic, 12 yrs exp. yada yada yada)

Assume that he was running 16lbs of boost with his stock BOV. Assume further that his stock BOV was leaking ~3psi boost pressure at >12PSI. This would force him to make his turbo run @19lbs of boost, even though only 16psi was being registered at the intake manifold. As soon as he changed BOV's, his boost would be running at 19psi. The stock fuel system on this car can only handle about 16-17psi before it hits fuel cut. Thus the requirement for altering his MBC settings.

-EngineBuilder

edit: I do not disagree that there is the possibility that his BOV is opening before it should; however this would feel more like a gradual loss of power at higher RPM's; from the statement: I believe that he is hitting fuel cut- the only reasonable explanation for this is that he is producing more boost than his fuel system can handle. Not that he is losing boost through a prematurely opening BOV.

Takers on the $10 bet?

 

I agree with that, It definetly sounds like fuel cut.

 

the boost has not been touched. hes still got the stock selonoid on there.this problem happens at WOT.

 

Is the problem occuring at WOT with the stock plastic BOV?

As the others were mentioning, sounds like the bov is opening to early. Possibly a bad spring or diaphragm in the bov?

 

holy crap same thing happens to me. just sometimes, but when i lean it out a little around 5000, it makes it stop.

 

Thank you for sparing me

but for real, i wasnt trying to flame you. Either way thanks for explaining what you meant without going off the deep end. and welcome to the board