LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Bigger cam+catalytic converter=more smoke from exhaust until warmed up?

Thread Tools
 
Search this Thread
 
Old 03-15-2004, 06:48 PM
  #1  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
Bigger cam+catalytic converter=more smoke from exhaust until warmed up?

My car has been smoking more than normal lately, but if it does it it's only when I first start it up in the morning, smokes for about ten minutes then stops. It's like the car is running rich while warming up, smoking, then when it quits running rich the smoke stops. Anyone else had this happen?

It's a HOTcam, ported heads, random tech high flow cat, PCMforless tune.......
FastZinTennessee is offline  
Old 03-15-2004, 07:32 PM
  #2  
Registered User
 
Don't Look Back's Avatar
 
Join Date: Sep 2002
Location: Roselle Park, NJ
Posts: 387
I know mine smokes like a bastard on cold mornings. No cam, but I have a gutted cat. Makes sense that a high flow cat and a bigger cam would act the same. I think the smoke is a result of the AIR pump until it shuts off.
Don't Look Back is offline  
Old 03-15-2004, 08:20 PM
  #3  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
I've removed my air pump. This really freaked me out because I thought all the smoke was a blown headgasket, but the guys I know at the mechanic shop ran a few tests and said for sure that I don't. The smoke gets pretty bad sometimes.

If more smoke than usual is normal I'll live with it, just kind of unnerving to look in the rearview and see a plume of smoke at stoplights
FastZinTennessee is offline  
Old 03-15-2004, 08:47 PM
  #4  
Registered User
 
Don't Look Back's Avatar
 
Join Date: Sep 2002
Location: Roselle Park, NJ
Posts: 387
Even without the AIR pump, i'd think its normal. Mine smokes out the street some mornings.
Don't Look Back is offline  
Old 03-15-2004, 08:52 PM
  #5  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
Ok great, that makes me feel better

Anyone else?
FastZinTennessee is offline  
Old 03-15-2004, 11:24 PM
  #6  
Registered User
 
Terran2k's Avatar
 
Join Date: Aug 2002
Location: texas
Posts: 986
mine is basically stock, and on cold days when i start her up for the 1st time that day, she'll smoke it up till the moisture evaporates that had condensed in the exhaust.
Terran2k is offline  
Old 03-16-2004, 12:22 AM
  #7  
Registered User
 
Indy93Z28's Avatar
 
Join Date: Oct 2002
Location: Bay Area, CA
Posts: 348
Mine has a lot more smoke when cold than before. Big ol white cloud forms at the beginning. It wasn't as much before cam. I did notice that my car stopped producing smoke faster than my friends none cammed cars tho while getting warm..
Indy93Z28 is offline  
Old 03-16-2004, 12:54 AM
  #8  
Registered User
 
6Speed's Avatar
 
Join Date: Feb 1999
Location: Tuscaloosa
Posts: 542
How many miles are on it? It could be the rings. When it warms up they expand enough to seal up, but when it's cold it might burn a little oil.
6Speed is offline  
Old 03-16-2004, 10:10 AM
  #9  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
It's definitely white smoke...... 138k miles.

The guy I know that works at the mechanics shop said that if a car is loading up on fuel then it can produce more white smoke that usual out of the exhaust. He said that he had a car come in with an injector stuck open and it was pouring white smoke out.

I think maybe the tune on the car is programmed to dump a lot of fuel in while the car is warming up to "light off" the catalytic converter. This might be even more so since I have a PCMforless tune, as I'm not sure if it's running richer at idle now.
FastZinTennessee is offline  
Old 03-16-2004, 10:22 AM
  #10  
Registered User
 
2MCHPSI's Avatar
 
Join Date: Dec 1999
Location: Annapolis Md. USA
Posts: 754
white smoke sounds like oil, not runnng rich.. Most likely your predefined cold start fuel trim values are on the rich side. When it hits closed loop, it takes over and is ok.
2MCHPSI is offline  
Old 03-16-2004, 04:36 PM
  #11  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
I thought oil was blue or darker colored smoke......
FastZinTennessee is offline  
Old 03-16-2004, 04:38 PM
  #12  
Registered User
 
Don't Look Back's Avatar
 
Join Date: Sep 2002
Location: Roselle Park, NJ
Posts: 387
Yeah, it is. I know mine smokes white, and when you stand behind it, you can smell fuel. If it were bluish and smelt like burning oil, than that would be the problem.
Don't Look Back is offline  
Old 03-16-2004, 04:38 PM
  #13  
Registered User
 
2MCHPSI's Avatar
 
Join Date: Dec 1999
Location: Annapolis Md. USA
Posts: 754
blue and dark smoke is most likely running rich.
2MCHPSI is offline  
Old 03-16-2004, 04:55 PM
  #14  
Registered User
Thread Starter
 
FastZinTennessee's Avatar
 
Join Date: Mar 2001
Location: Costa Mesa, CA
Posts: 2,521
This might be a good excuse to buy a wideband and get a dyno tune
FastZinTennessee is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
QuickSilver02
Midwest
1
04-07-2015 11:12 AM
captcorvette
Computer Diagnostics and Tuning
2
03-07-2015 12:37 PM
MattFick
LT1 Based Engine Tech
9
02-15-2015 10:16 PM
dale3in98
Cars For Sale
0
02-14-2015 12:18 PM



Quick Reply: Bigger cam+catalytic converter=more smoke from exhaust until warmed up?



All times are GMT -5. The time now is 05:53 AM.