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

Lt1 not running correctly

Thread Tools
 
Search this Thread
 
Old 01-25-2011, 02:16 AM
  #1  
TECH Enthusiast
Thread Starter
iTrader: (2)
 
henry172's Avatar
 
Join Date: Jul 2006
Posts: 533
Likes: 0
Received 0 Likes on 0 Posts
Default Lt1 not running correctly

I have a 1997 TA that seems to be running a little off to me. It also burnt nearly 2qts of oil in less than 3,000mi. I did a compression/leak down test and everything turned out O.K. It looks like unburnt oil is exiting the exhaust; I am starting to think a couple exhaust valve seals or seats are bad. I think I may have hurt the heads when I first installed the cam and really did not know how to set up the timing chain; I installed a adjustable double chain. I put the chain on way off of where it should have been; it was so bad that the headers were glowing red/orange and melted in a few spots. So if it melted the headers what is the chance I damaged some exhaust seals? Last time I had the headers off I also noticed the ports on the heads were extremely black. The car runs bad at Idle, clears up with more throttle, but hesitates for a brief second if I floor it all at once.
Old 01-25-2011, 10:56 AM
  #2  
TECH Veteran
iTrader: (246)
 
robsquikz28's Avatar
 
Join Date: Mar 2008
Location: Chicago/Crown point
Posts: 4,987
Received 0 Likes on 0 Posts

Default

If thats the case you probably bent the valves on the heads!!!
Old 01-25-2011, 12:27 PM
  #3  
TECH Addict
iTrader: (1)
 
jaycenk's Avatar
 
Join Date: Jun 2009
Location: Holiday, FL
Posts: 2,210
Received 1 Like on 1 Post

Default

Sounds rich. Maybe you burned up the O2's with the mistake? They can take heat but if it was bad enough to melt the headers then I say the O2's are toast. If it was lean the ports would look white or ashy. Black soot is carbon from unburned fuel.
Old 01-25-2011, 12:59 PM
  #4  
TECH Enthusiast
Thread Starter
iTrader: (2)
 
henry172's Avatar
 
Join Date: Jul 2006
Posts: 533
Likes: 0
Received 0 Likes on 0 Posts
Default

I replaced the o2 sensors. It smells at idle but no smoke unless I rev it up above 4,500rpms in park. The oil is going some somewhere; almost 2qts in 3,000mi is a lot of oil. If It passed the compression and leak down test then it has to be the seals in the heads correct. The exhaust ports look like this
Old 01-25-2011, 02:08 PM
  #5  
TECH Addict
iTrader: (1)
 
jaycenk's Avatar
 
Join Date: Jun 2009
Location: Holiday, FL
Posts: 2,210
Received 1 Like on 1 Post

Default

Originally Posted by henry172
If It passed the compression and leak down test then it has to be the seals in the heads correct.
Old 01-25-2011, 02:24 PM
  #6  
TECH Enthusiast
Thread Starter
iTrader: (2)
 
henry172's Avatar
 
Join Date: Jul 2006
Posts: 533
Likes: 0
Received 0 Likes on 0 Posts
Default

Would bad seals cause it to run just slightly off? It is not running too bad, it is bad at first start up, then clears up and it gets worse once it is running for a couple min. Looks like I am going to up grade the heads to LE1 or something similar to them.
Old 01-25-2011, 03:59 PM
  #7  
TECH Addict
iTrader: (1)
 
jaycenk's Avatar
 
Join Date: Jun 2009
Location: Holiday, FL
Posts: 2,210
Received 1 Like on 1 Post

Default

Just look at the exhaust ports. They are coated. What do your plugs look like? That port is even wet at the top so unless that is from the valve cover I think that may be your answer. Look at the valve stem on the right of that pic. It is coated as well and the other has a light ash left over from getting it to hot. It is probaply not all of them that are leaking but a couple doing that and oil fouling those few plugs will cause that.
Old 01-25-2011, 04:45 PM
  #8  
TECH Enthusiast
Thread Starter
iTrader: (2)
 
henry172's Avatar
 
Join Date: Jul 2006
Posts: 533
Likes: 0
Received 0 Likes on 0 Posts
Default

Those are not my heads just a example of what mine look like. I do have fouled plugs in two cylinders 8, and 7. They just look a little black only 1000mi on them, but they smell like oil and will more than likely get worse with more use. Cylinder 3 also looks like it is having a problem, but not as bad as 8 and 7.



Quick Reply: Lt1 not running correctly



All times are GMT -5. The time now is 05:47 AM.