LT-1 Problem
Thread Starter
Instructor
Joined: Jul 2001
Posts: 243
Likes: 0
From: Miami Fl
LT-1 Problem
Okay When I start it up it sounds Like Miss Fires For a second And than it runs Fine But When I Rev it up It shoots Black Smoke What Could it Be
Feul Pressure is 38 Psi
Thanks
Feul Pressure is 38 Psi
Thanks
Pro
Joined: Nov 2000
Posts: 703
Likes: 2
From: Cypress Texas
Re: LT-1 Problem (YellowC4)
I had a similar problem and it was my oxygen sensor going out. I first noticed that it would miss on start up and then after it
warmed up or with AC on it had a noticeable miss. The sensor tells the car how much gas to send to the injectors and when it
starts to read faulty, it will give too much gas and cause black smoke to pour out of usually one of the exhaust tips. The LT-1's
have an injector on each side of the exhaust, so if one pipe seems to smoke more than the other, it is probably the side that
is out. On a side note, the GM garage did not catch this when I brought it in and said that they could not find any problems, I
looked myself with a scanner later and could see the left oxygen sensor consistently dropping in voltage thus causing the rich
condition and the smoke. Hope this helps.
warmed up or with AC on it had a noticeable miss. The sensor tells the car how much gas to send to the injectors and when it
starts to read faulty, it will give too much gas and cause black smoke to pour out of usually one of the exhaust tips. The LT-1's
have an injector on each side of the exhaust, so if one pipe seems to smoke more than the other, it is probably the side that
is out. On a side note, the GM garage did not catch this when I brought it in and said that they could not find any problems, I
looked myself with a scanner later and could see the left oxygen sensor consistently dropping in voltage thus causing the rich
condition and the smoke. Hope this helps.
Race Director
Joined: Oct 2001
Posts: 12,832
Likes: 209
From: Canton GA
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St. Jude Donor '03-'05-'06-'10-'11-'12
Re: LT-1 Problem (YellowC4)
Hmmm... sounds like a leaky injector to me... especially if it is smoking right at startup. One of the cylinders is flooding while the car is off causing a fouled plug (hence the severe miss). Narrow down the possibilities by watching which pipe the smoke comes out of and then pull the plugs on that side of the engine until you find one that is more carboned than the others. That should be the bad injector cylinder.
Drifting
Joined: Nov 2001
Posts: 1,587
Likes: 0
From: Omaha NE
Re: LT-1 Problem (YellowC4)
You can't really check them, you have to replace them. Depending on what year you have: Up until '92-'93 you have 2, '94 you have 3, '95-'96 you have 4. They are plugged into your exhaust, they're very easy to find.
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