GM S/C... Help!!!... 13psi?!?! - Boost Forum

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GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 12:22 AM
I was out drivign pretty spirited when i ran across a puddle
After hitting the puddle i noticed a whisp or two of steam off the engine
At any rate after that the car acts like its getitng no fuel after about 4500
The charger is whining and the whole nine but the RPMs refuse to rise
Also here is the wierd part, the bypass valve is closing under pretty easy loads
and at full throttle I'm seeing 13 Psi!!!, untill it falls flat.
Oh and it drives fine under non-boost loads
What the heck is going on?
Any ideas?
All the conections are fine nothing looks out of the ordinary then again it is 1 in the morning.
I'll check again in the morning
Thanks in advance



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)


Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 8:36 AM
?? whats up with ur track times



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 8:39 AM
^^^ Thats what I was just looking at too lol!



Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 8:51 AM
I was running browntops and no reflash at the the time
but more importantly why the extra psi?



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 3:00 PM
Well I looked at it in the daytime, Everything seems visually okay
but the symptoms mentioned above are still present.
And in addition when the bypass valve first closes i see 6psi and it just rises (sometimes as high as 13psi, yikes) untill it falls flat on its face.
Anybody have any idea on this? Luckly it still putts around
as long as I stay out of boost.
If anybody can help me its the org.



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 3:52 PM
hmm do you have the stock pulley?






Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 5:06 PM
2.7in



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
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Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 5:21 PM
maybe something broke in the valvetrain. the only way you can get the charger to put out 13 psi is spinning it with a very small pully. maybe your lifters arent working as they should and not releasing the pressure in the combustion chamber and the pressure will backflow through the supercharger showing the 13 psi.



Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 5:31 PM
Bad boost gauge?






Re: GM S/C... Help!!!... 13psi?!?!
Sunday, August 21, 2005 5:44 PM
I already tried taking the guage out of the equation, problem still persists
Before when i gave it partial throttle I would see 1-2 psi, now I see 6 psi, right
off the bat and from there it climbs to 13 psi, at which point it acts as if its getting no fuel
and sputters until no boost is seen again.
The kicker is it drives fine w/o boost.
I duuno Hopefully someone has an idea



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Monday, August 22, 2005 11:16 AM
maybe the s/c is broke? well let's think abtou this here, you said you hit a puddle and then this problem presisted(started). . . any ways you say the car acts as if it has no fuel and spudders around, i'd say to THOUROOUGHLY(<--- can't spell) check all your fuel lines and then check all of the vacuum lines.

" ..TQ is SPEED, HP is BRAGGING RIGHTS.. "


Re: GM S/C... Help!!!... 13psi?!?!
Monday, August 22, 2005 6:25 PM
All the lines look fine,

I want to attribute the problem the supercharger as well,
however it still "sounds" as if its working and there is no visible damage on the outside.
I wanted to say fuel, but the high boost and the fact drives normal under no boost steered me away from that.

Is it possible i have bad MAP sensor?, would the symptoms be present under a non boosted load?
If it is the S/C, what could be wrong with it. and on the same lines what would make a GM S/C see 13 psi wheter it be engine,valvetrain or S/C?

If anybody is holding back any ideas, nows not time to be timid
Thanks



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Monday, August 22, 2005 9:19 PM
Maybe your cat is clogged.I dont think it would make the s/c hit 13 psi from the back pressure,but it would def make the car sputter in the higher rpm.Go to a muffler shop and have them put in a straight pipe and see if that fixes the problem.


Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust

Re: GM S/C... Help!!!... 13psi?!?!
Monday, August 22, 2005 10:03 PM
would my cat being clogged throw a code b/c i have yet to see one



Save a Tranny, Roll-on
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Re: GM S/C... Help!!!... 13psi?!?!
Tuesday, August 23, 2005 6:22 AM
i say cat too


see ya!

Re: GM S/C... Help!!!... 13psi?!?!
Tuesday, August 23, 2005 8:15 AM
Id sure like to believe that , I'll go have it checked out today,
If it is the cat it will be the second stock cat ive taken down in 2 years



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Tuesday, August 23, 2005 12:19 PM
Well i took it to an exhuast shop and they confirmed it was the cat. As i speak my car is at GM being replaced "under warrenty"(we'll see).
Thanks for all your help gentlemen I'll keep you posted.



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

Re: GM S/C... Help!!!... 13psi?!?!
Tuesday, August 23, 2005 1:06 PM
If it is a clogged cat then why all of a sudden would it start doing that after he went through a puddle with the car off?



Re: GM S/C... Help!!!... 13psi?!?!
Tuesday, August 23, 2005 8:48 PM
That is the same question I'm pondering over...
Maybe it was just a coinendence(sp?), For sure the cat is
clogged. But maybe there is more? We'll see friday when i get
my car back.



Save a Tranny, Roll-on
15.3@88m.p.h.(I/E)
15.2@94m.p.h.(S/C'd)
15.5@89m.p.h.(Stock GTP)

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