gas in plenum brake booster?
01-11-2011, 05:19 PM
#1
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Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)
gas in plenum brake booster?
i was thinking a hole in the diaphragm of the fuel pressure regulator.. i cant test for pressure drop because the hose in the tank is leaking so the pressure just drops.. im going to vacuum test the FPR and possibly narrow it down to stuck injector because i do get a slight miss when accelerating but it goes away sometime.. damn two stroke oil gas from last month i bet grrr..i just built a moped too. haha
01-11-2011, 05:58 PM
#2
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Re: gas in plenum brake booster?
To test for a broken regulator diaphram, just remove the vacuum hose from the regulator with the engine running. If the diaphram is broken, fuel will run out of the vacuum port.
01-11-2011, 06:24 PM
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Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)
Re: gas in plenum brake booster?
MAN!!! that sucks. YEAH it is the diaphragm. ughh...no wonder my gas milage is shitty... damn it. i have to remove the plenum and fuel rails now huh.. so o-rings plenum gaskets what else..gaskets do i need. i built a moped but no handle bars ugh.
01-11-2011, 06:38 PM
#4
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Re: gas in plenum brake booster?
You'll need runner gaskets and a fuel pressure regulator diaphram. Don't stress, the job isn't that bad. Just loosen the runner attaching bolts at the lower intake. Then remove the runner to plenum bolts and lift the plenum out. Be sure to disconnect all wirng and vacuum lines as you go. The MAT sensor is on the bottom of the plenum and you want to be sure you get it plugged back in before you bolt up the plenum. The diaphram is held to the regulator by six screws. Remove the screws and diaphram. With the plenum off, remove the runner to lower intake bolts and replace the gaskets. Then reverse procedure to reassemble.
01-11-2011, 06:44 PM
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Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)
Re: gas in plenum brake booster?
i need the size for the torx bolt head for plenum
01-11-2011, 08:18 PM
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Car: 85' Trans Am !best car ever!
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Re: gas in plenum brake booster?
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Last edited by transam85dudeman; 01-12-2011 at 05:03 AM.
01-11-2011, 11:13 PM
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Re: gas in plenum brake booster?
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Last edited by transam85dudeman; 01-12-2011 at 05:03 AM.
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01-11-2011, 11:17 PM
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Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)
Re: gas in plenum brake booster?
after minutes of searching i guess t-40 is the right size. laters
01-12-2011, 12:58 AM
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Car: 1988 camaro z28,1997 camaro lt1
Engine: 355 afr 195 heads,tpis big mouth
Transmission: 700r-4 built by me 3-4 z pack
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Re: gas in plenum brake booster?
T-40 is right and for the regulator bolts its a t-10 tamper
01-12-2011, 09:17 AM
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Car: 85' Trans Am !best car ever!
Engine: 305tpi 215hp LB9 two bolt,
Transmission: th-700r4
Axle/Gears: stock (3.27)
Re: gas in plenum brake booster?
well i replaced it last night, 
it works
it works Last edited by transam85dudeman; 01-14-2011 at 06:01 AM.
01-12-2011, 01:12 PM
#11
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Re: gas in plenum brake booster?
LOL. Thanks for the props man. It makes feel all warm and fuzzy. I see you took a short cut on the lower runner gaskets. Its okay though. Im sure they're fine. You can pull the plenum without loosening the lower runner to manifold bolts. I just like to reseal everything while Im in there. Good job and happy motoring.
03-02-2011, 03:12 PM
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Car: 89 Iroc z camaro
Engine: 350 TPI
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Re: gas in plenum brake booster?
Ok i read this and im kinda a newb so i halfway understood all that haha, so im getting horribal mpg and i cant figure it out so i wanna know what hose to do to test this? like i need it in very basic terms haha 
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