Boost raised???

[attackdog]

Hi all. I have a 20g14cm2 ported turbo on the SY and have noticed the boost has raised while at idle and under normal driving conditions. On the aftermarket boost gauge it used to read around -13 at idle and around -20 getting out of the gas from a heavy acceleration. Now it reads -5/-8 at idle and -10/-11 getting out of the gas. The WOT boost levels are the same at 25#'s. The fuel pressure has not changed. What would cause this to change? Thanks.
-Dean

 

[cameronsclone]

Re: Boost raised???

Negative boost is just vacuum, so maybe you have a vacuum leak. Do you still have the plastic stockers? If so there's most likely a broken elbow or cracked line somewhere in there.

 

[James Thomas]

Re: Boost raised???

Yea sounds like a vacume leak related issue. As stated above, these trucks are 15-17 years old now and the high under hood temps make all the (most of any way) O.E.M. rubber and plastic as crispy as a cracker. Check ever line, fitting and plastic elbow and replace.

________
James

 

[attackdog]

Re: Boost raised???

Is there a way to test for a vaccuum leak? Any special tools or homemade ones? Thanks again guys.
-Dean

 

[TYTILIDIE]

Re: Boost raised???

you can make yourself a leak tester. Sounds like a VAC leak to me too, or maybe even IAC.

http://www.syty.net/forums/showthread.php?t=48049&highlight=leak

 

[attackdog]

Re: Boost raised???

you can make yourself a leak tester. Sounds like a VAC leak to me too, or maybe even IAC.

http://www.syty.net/forums/showthread.php?t=48049&highlight=leak

Thanks again.
-Dean

 

[Flyin Ryan]

Re: Boost raised???

you can also try the bike tube method

http://www.sytyarchives.com/howto/viewarticle.php?article_name=find_vacuum_leak.php&dir=engine