LT1-LT4 Modifications 1993-97 Gen II Small Block V8

If you seem to have a vacuum leak...

Thread Tools
 
Search this Thread
 
Old 09-05-2009, 10:46 PM
  #1  
TECH Enthusiast
Thread Starter
iTrader: (7)
 
96blackta's Avatar
 
Join Date: Sep 2008
Location: Orange County
Posts: 526
Likes: 0
Received 0 Likes on 0 Posts
Default If you seem to have a vacuum leak...

Tear out all your emissions, lol. Finished removing all the emissions components, and turns out I had a vacuum leak in the evap system. My idle hasn't been this smooth since I bought the car over a year ago. And my brake booster seems more powerful now too.
Old 09-06-2009, 07:35 AM
  #2  
TECH Veteran
 
shbox's Avatar
 
Join Date: Dec 2008
Location: Little Rock, AR
Posts: 4,128
Received 54 Likes on 48 Posts
LS1Tech 10 Year
Default

How about finding and fixing your vacuum leak, instead? That works, too.
Old 09-06-2009, 08:13 AM
  #3  
TECH Veteran
iTrader: (1)
 
leadfoot4's Avatar
 
Join Date: Sep 2005
Location: Webster, NY
Posts: 4,609
Received 4 Likes on 4 Posts

Default

Originally Posted by shbox
How about finding and fixing your vacuum leak, instead? That works, too.
Are you serious?? That takes time and effort!!









Old 09-06-2009, 09:22 AM
  #4  
TECH Veteran
 
shbox's Avatar
 
Join Date: Dec 2008
Location: Little Rock, AR
Posts: 4,128
Received 54 Likes on 48 Posts
LS1Tech 10 Year
Default

Originally Posted by leadfoot4
Are you serious?? That takes time and effort!!









LOL, yeah, probably less time that ripping it all out. Finding a vacuum leak is a pretty easy task.
Old 09-06-2009, 10:07 AM
  #5  
On The Tree
iTrader: (3)
 
illusions's Avatar
 
Join Date: Jul 2009
Location: Summerville, SC
Posts: 127
Likes: 0
Received 0 Likes on 0 Posts
Default

you might need to get use to the smell of gas with no evap system
Old 09-06-2009, 10:30 AM
  #6  
11 Second Club
iTrader: (3)
 
86formula's Avatar
 
Join Date: Oct 2006
Posts: 879
Likes: 0
Received 0 Likes on 0 Posts
Default

ive actually heard it doesnt smell at all if you put a small breather filter on the end of the line near the tank (ill be doing this)
Old 09-06-2009, 02:06 PM
  #7  
TECH Addict
iTrader: (15)
 
flyinZ's Avatar
 
Join Date: Jun 2002
Location: IL
Posts: 2,642
Likes: 0
Received 0 Likes on 0 Posts

Default

Dumb question..how do you find, a vacuum leak? If your not entirely sure you have one..
Old 09-06-2009, 03:47 PM
  #8  
TECH Enthusiast
 
Smoke Em's Avatar
 
Join Date: Mar 2009
Location: RI
Posts: 722
Likes: 0
Received 0 Likes on 0 Posts
LS1Tech 10 Year
Default

was your car surging at idle??
Old 09-06-2009, 06:01 PM
  #9  
TECH Veteran
iTrader: (1)
 
leadfoot4's Avatar
 
Join Date: Sep 2005
Location: Webster, NY
Posts: 4,609
Received 4 Likes on 4 Posts

Default

Originally Posted by flyinZ
Dumb question..how do you find, a vacuum leak? If your not entirely sure you have one..


If it's a serious one, you can actually hear the hissing. More subtle leaks will cause high idle speeds, (lean) surging, as "Smoke Em" mentioned.
Old 09-06-2009, 06:27 PM
  #10  
TECH Addict
iTrader: (15)
 
flyinZ's Avatar
 
Join Date: Jun 2002
Location: IL
Posts: 2,642
Likes: 0
Received 0 Likes on 0 Posts

Default

Only reason I ask, is I THINK I have a high idle issue. Not entirely sure what my tuner set it at, when I did a mail order, to get my car going.
Old 09-06-2009, 06:30 PM
  #11  
TECH Enthusiast
 
Smoke Em's Avatar
 
Join Date: Mar 2009
Location: RI
Posts: 722
Likes: 0
Received 0 Likes on 0 Posts
LS1Tech 10 Year
Default

mine only surges when its idling for a long time or putting around at 10 mph at the most for 10 mins or more
Old 09-06-2009, 08:16 PM
  #12  
TECH Enthusiast
Thread Starter
iTrader: (7)
 
96blackta's Avatar
 
Join Date: Sep 2008
Location: Orange County
Posts: 526
Likes: 0
Received 0 Likes on 0 Posts
Default

You could hear a hissing in the engine bay when the brake was applied. I occasionally had a surging idle, but mostly it was just high.

The gasoline smell is only occasional, and it's no so bad either.
Old 09-06-2009, 11:06 PM
  #13  
TECH Junkie
iTrader: (22)
 
camar0corey's Avatar
 
Join Date: May 2006
Location: Spring Hill, FL
Posts: 3,974
Likes: 0
Received 2 Likes on 2 Posts

Default

Hmm wonder if I have a vacuum leak, can it hiss just sitting there at idle? Sometimes it idles high, but seems to come down after 5 seconds or so. I do have this strange sound though I haven't been able to figure out what it is. Its been like this for 15k+ miles, so I'm assuming its nothing mechanical.
Old 09-07-2009, 07:34 AM
  #14  
TECH Veteran
iTrader: (1)
 
leadfoot4's Avatar
 
Join Date: Sep 2005
Location: Webster, NY
Posts: 4,609
Received 4 Likes on 4 Posts

Default

Originally Posted by camar0corey
Hmm wonder if I have a vacuum leak, can it hiss just sitting there at idle? Sometimes it idles high, but seems to come down after 5 seconds or so. I do have this strange sound though I haven't been able to figure out what it is. Its been like this for 15k+ miles, so I'm assuming its nothing mechanical.
There are a LOT of rubber hoses under the hood of a 4h gen, especially an LT1 car. Rubber will crack over time. Check the PCV hook-up, and the RH valve cover to the throttle body vent line, as those two have large OD rubber lines to them. The power brake booster has a large OD vacuum line, and there are a couple of rubber lines on the RH front of the intake, IIRC that hook up to the MAP sensor....
Old 09-07-2009, 08:44 AM
  #15  
12 Second Club
 
1mean96ss's Avatar
 
Join Date: Aug 2006
Location: St.Peters Mo
Posts: 286
Likes: 0
Received 0 Likes on 0 Posts

Default

Post some pics of your intake please, lets see how it cleaned everything up
Old 09-07-2009, 12:46 PM
  #16  
TECH Enthusiast
Thread Starter
iTrader: (7)
 
96blackta's Avatar
 
Join Date: Sep 2008
Location: Orange County
Posts: 526
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by 1mean96ss
Post some pics of your intake please, lets see how it cleaned everything up
I'll get a pic when I can, but my engine bay isn't anything to brag about yet.
Old 09-07-2009, 01:36 PM
  #17  
TECH Enthusiast
Thread Starter
iTrader: (7)
 
96blackta's Avatar
 
Join Date: Sep 2008
Location: Orange County
Posts: 526
Likes: 0
Received 0 Likes on 0 Posts
Default







Engine bay still needs work. Need to get rid of cruise control and tuck in that throttle cable for starters. Maybe an elbow too.
Old 09-07-2009, 02:03 PM
  #18  
TECH Senior Member
iTrader: (2)
 
RamAir95TA's Avatar
 
Join Date: May 2005
Location: South Jersey
Posts: 9,467
Likes: 0
Received 7 Likes on 7 Posts

Default

Cruise control isn't ugly, it's the TCS module that has to go!
Old 09-07-2009, 02:23 PM
  #19  
TECH Enthusiast
Thread Starter
iTrader: (7)
 
96blackta's Avatar
 
Join Date: Sep 2008
Location: Orange County
Posts: 526
Likes: 0
Received 0 Likes on 0 Posts
Default

I don't use TCS anyway. Where is the module?
Old 09-07-2009, 05:54 PM
  #20  
TECH Veteran
iTrader: (1)
 
leadfoot4's Avatar
 
Join Date: Sep 2005
Location: Webster, NY
Posts: 4,609
Received 4 Likes on 4 Posts

Default

Originally Posted by 96blackta
I don't use TCS anyway. Where is the module?
That big, black box over the LH valve cover.....


Quick Reply: If you seem to have a vacuum leak...



All times are GMT -5. The time now is 05:40 PM.