LT1 Idle shake
Originally Posted by carzman5678
My car ran fine in closed loop. When the car goes into Open loop it reads from the O2 sensors, which optimizes the air and fuel for emissions and MPG.
Tanner,
I'll try that this weekend, i bet it needs to be cleaned any way.
I have had this car for 7 years, most of which with a poly trans mount, it wouldnt cause the car to shake like it does at idle. I know what normal idle shake is like, barley noticable, this is very noticable.
I'll try that this weekend, i bet it needs to be cleaned any way.
Originally Posted by @nthony
its a normal LT1 thing.
when you get poly mounts itll go away but youll feel it in the car.
when you get poly mounts itll go away but youll feel it in the car.
I have had this car for 7 years, most of which with a poly trans mount, it wouldnt cause the car to shake like it does at idle. I know what normal idle shake is like, barley noticable, this is very noticable.
TECH Fanatic
Joined: Oct 2006
Posts: 1,106
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From: POULSBO WA.
I think you have that backwards, the car reads from the 02s in closed loop, and has a set peramiter in open loop. My car runs a whole lot better in open loop, so I unplugged one of the 02 sensors. As for the coated headders the non heated 02s have a hard time heating up to 600 deg where they start to work that is why people do the heated conversion when they put them on.
Staging Lane
Joined: Jul 2006
Posts: 93
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FAD2BLK has it right. There's a very well written article at http://members.aol.com/InjuneerZZ/ScanMast.htm, which is primarily an explanation of what you can learn from the ScanMaster diagnostic gizmo. The pertinent discussion of open loop/closed loop is about halfway down the page, at INTRODUCTION - AIR/FUEL MANAGEMENT MEASUREMENTS:
Cheers -- Gary
Cheers -- Gary
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Registered User
Joined: Jul 2019
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Lt1 Shake problem So my 1994 Firebird lt1 has an odd shake problem. It seems to be random. While driving it will shake once, twice, or maybe even a few times. After this it is fine for a little while. During some drive cycles, it may only do it once or not even at all. It kind of feels like if you shift in a car when you have a really hard shift kit in it, accept its random. Any ideas?
Staging Lane
Joined: Feb 2019
Posts: 79
Likes: 5
From: Houston, Texas
I'd definitely scrutinize your O2 sensors if I were you. My car did exactly what you're describing when I had a bad 02 sensor; it would run perfectly when cold, but as soon as it went into open loop the AFR would drop to super lean when the pedal wasn't being pressed. It would shake and sputter sitting at stop lights like it was about to die but never would, and as soon as I started moving again it would be fine
My car idles much better in open loop these days. I've noticed this since I put it back on the road. As soon as our goes closed loop the sound changes completely. I've ran 112 leaded through it allot though and I'm thinking the O2's are pissed at me. Next on my agenda is a good Throttle body cleaning and new O2'S
