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My boost changes frequently.. question.

1341 Views 13 Replies 8 Participants Last post by  redfox
I have an Auto Prelude Si.
in first gear at full boost its 7lbs.
the auto holds boost (unlike sticks) but it drops it to 5lbs max. in 3rd it goes up a bit to 6psi.
can any other Auto Turbos explain this?
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you might not be getting enough fuel. check all hoses for leaks. just a possibility.
are you running lean?
check the fmu and do you have a fuel pump.. try to up the fuel pressure and check the spark plugs to see if your running rich or lean and it would help if you had a EtG gauge ... good luck..
When I went to the dyno the AF gauge went out while on my car. So I cant tell exactly what Im running at A/F wise. I have the Vortech FMU with Fuel Pump. I think it might be the tranny too.
Yeah I think its the Auto tranny..
How would your tranny affect boost level??
Its like this.. On a stick when you shift it blows off and then reboosts to get to the desired level. On an auto tranny it builds boost and when it shifts it doesnt blow off if your flooring it.
It shifts to the next gear and slightly drops to 1-2psi and stays there until the next shift when it goes up again.
My guess is that when it drops to a lower RPM after it shifts the fuel pressure changes causing the change in boost. But why it doesnt build back up to the max boost is beyond me.
The only thing i can think off is checking your wastegate and the fuel pressure... good luck..
check your waste gate it might be bleeding off pressure also check all the vacuum lines if any are loose you may be also loosing pressure there.
how would the plugs look if you are running rich or lean?
if your running rich your plugs will have black soot cake all over. If your running lean the plug will have a like white tip. Brown by the threads if the plug has cooling problems.
I heard something like you are not supposed to use Platinum sparks for F/I'ed engines. Am I on the ball?
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