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

Cammed lt1 runnin rich idleing high

Thread Tools
 
Search this Thread
 
Old 01-20-2009, 11:01 PM
  #1  
Shirley Temple Drinker
Thread Starter
iTrader: (1)
 
Sgt. Spuds's Avatar
 
Join Date: Oct 2005
Location: IL
Posts: 3,333
Likes: 0
Received 0 Likes on 0 Posts
Default Cammed lt1 runnin rich idleing high

I did a motor swap a while back and have been slowly pecking away at the car trying to get it on the street this spring, a year behind schedual.... car ran like crap for a while and after tweaking this and that and a new opti it seems to start and run fine. I put LT headers on at the same time so I need an exhaust, but I figured that would be the last thing I did, since I dont need it streetable yet. Even tho the cars running better and starting good, it still smells a bit rich and idles high, could the exhaust help this? if the open lts are the problem wouldnt unplugging the o2s eliminate the problems? pcm for less tune btw
Old 01-20-2009, 11:20 PM
  #2  
11 Second Club
iTrader: (6)
 
speed_demon24's Avatar
 
Join Date: Dec 2001
Location: Ocala, FL
Posts: 4,609
Likes: 0
Received 2 Likes on 2 Posts

Default

A cam that size is going to have a very noticeable smell at idle. You could try putting cats on it but all that did was give me the rotten egg smell all the time instead so I took them off.
Old 01-21-2009, 10:17 AM
  #3  
TECH Senior Member
iTrader: (36)
 
ss.slp.ls1's Avatar
 
Join Date: Jan 2008
Location: Orange County, CA
Posts: 8,188
Received 26 Likes on 24 Posts

Default

Originally Posted by Sgt. Spuds
I did a motor swap a while back and have been slowly pecking away at the car trying to get it on the street this spring, a year behind schedual.... car ran like crap for a while and after tweaking this and that and a new opti it seems to start and run fine. I put LT headers on at the same time so I need an exhaust, but I figured that would be the last thing I did, since I dont need it streetable yet. Even tho the cars running better and starting good, it still smells a bit rich and idles high, could the exhaust help this? if the open lts are the problem wouldnt unplugging the o2s eliminate the problems? pcm for less tune btw
The rich smell, I wouldn't be concerned about, especially with open headers. The high idle would concern me. You need to find out why it's not idling normal. I have a mail order tune and my tune is set for 750 rpms. You may have a vac leak, or a sticky IAC.
Old 01-21-2009, 10:22 AM
  #4  
Banned
iTrader: (12)
 
Elliott's94Z's Avatar
 
Join Date: Mar 2008
Location: Oregon Grown
Posts: 4,370
Likes: 0
Received 1 Like on 1 Post
Default

I think it would be a wise idea to have a "dyno" tune especially with a head/cam swap. I would't rely on a mail order with that set up.
Old 01-21-2009, 12:13 PM
  #5  
TECH Enthusiast
iTrader: (22)
 
Stroked96Bowtie's Avatar
 
Join Date: May 2007
Location: DFW, Tx
Posts: 739
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by ss.slp.ls1
The rich smell, I wouldn't be concerned about, especially with open headers. The high idle would concern me. You need to find out why it's not idling normal. I have a mail order tune and my tune is set for 750 rpms. You may have a vac leak, or a sticky IAC.
^^Some good points here about the vac leak or IAC. I would check for vaccum leaks first with a can of carb/brake cleaner if its not obvious like a briddle hose etc.

If its a new TB you might have to adjust the idler screw, make sure the blades are hanging to far open with no throttle applied...this will cause that also.

I had this same issue...was checking everything...after talking with my tuner he said some PCMs are just lazy and learn the new setup slower than others. The more drive time I put on my setup the better driveability got. Now idle problems are near to none, check fuel pressure and for codes also to be sure your opti isnt acting up.
Old 01-21-2009, 12:22 PM
  #6  
TECH Senior Member
iTrader: (36)
 
ss.slp.ls1's Avatar
 
Join Date: Jan 2008
Location: Orange County, CA
Posts: 8,188
Received 26 Likes on 24 Posts

Default

Another clue to a VAC leak would be a high long term fuel trim. You should get it scanned. If you are running open headers with o2's connected, you will want to runs some 18" extensions off of the headers or it will throw the o2's off and run like ****. But that's a separate issue from the high idle.
Old 02-15-2009, 03:12 AM
  #7  
Shirley Temple Drinker
Thread Starter
iTrader: (1)
 
Sgt. Spuds's Avatar
 
Join Date: Oct 2005
Location: IL
Posts: 3,333
Likes: 0
Received 0 Likes on 0 Posts
Default

belated thanks to u guys ill get it checked out
Old 02-15-2009, 10:01 AM
  #8  
TECH Fanatic
iTrader: (7)
 
Green3spd's Avatar
 
Join Date: Oct 2007
Location: Little Rock, Ar
Posts: 1,177
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by Stroked96Bowtie
The more drive time I put on my setup the better driveability got. Now idle problems are near to none
After my cam istall I had idle issues while coming to stops and applying brakes but after more time my driveability got much better, My car runs really good(NO-tune) but It does run a bit rich and under 1,800 it seems to studder but clears up instantly!

Put some miles on it...
Old 02-15-2009, 01:56 PM
  #9  
TECH Veteran
iTrader: (11)
 
infinitebird's Avatar
 
Join Date: Jul 2004
Location: Atlanta, GA
Posts: 4,280
Received 46 Likes on 35 Posts

Default

also check to make sure the MAF is not dirty or faulty.
Old 02-15-2009, 08:54 PM
  #10  
TECH Senior Member
iTrader: (36)
 
ss.slp.ls1's Avatar
 
Join Date: Jan 2008
Location: Orange County, CA
Posts: 8,188
Received 26 Likes on 24 Posts

Default

Originally Posted by Green3spd
After my cam istall I had idle issues while coming to stops and applying brakes but after more time my driveability got much better, My car runs really good(NO-tune) but It does run a bit rich and under 1,800 it seems to studder but clears up instantly!

Put some miles on it...
Hitting the brakes will cause the brake booster to evacuate some of the vacuum in the intake manifold. I would check for vacuum leaks.



Quick Reply: Cammed lt1 runnin rich idleing high



All times are GMT -5. The time now is 12:49 PM.