Carburetors Carb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.

high idle!!!!!!

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Old Nov 6, 2000 | 01:25 PM
  #1  
spitfire350's Avatar
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From: Arlington, TX,, USA
high idle!!!!!!

my camaro ildes somtimes in the mornings at about 1900 RPM! WTF??? I just replaced the choke heater relay that was burned up and i have no idea how long it was bad but my car has never idled so bad.

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keep the stang's far behind u and the cops even farther
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Old Nov 7, 2000 | 08:44 AM
  #2  
Damon's Avatar
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From: Philly, PA
The carb is supposed to idle at an elevated RPM when the choke is on/engine cold. Once the choke fully opens (about 2-5 minutes of driving depending on outside temperature) the idle will drop down to normal (750 or so).

I assume that your high idle is just TOO HIGH for your liking. Fortunately that's an easy fix. When the engine is full overnight cold take off the air cleaner and manually open the throttle 1/2 way to let the choke set. Then, standing in FRONT of the car look under the choke element/linkages and you will see a small hex-head bolt that also has a slot for a regular screw driver to fit in. That is your fast idle speed adjustment screw. Turn it about 1/2 turn counter-clockwise and your high idle should come down about 400-800 RPM. It should turn EASILY. If it doesn't don't force it- use a long penetrating oil soak and work it loose- they sometimes rust in place.

Please note that this screw ONLY adjusts idle speed when the choke is ON. Once the choke fully pulls off the idle speed is regulated ONLY by the regular idle speed adjustment screw on the driver's side of the carb.


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94 Firebird Formula M6- No options but Z rated tires. No mods over $10. 13.5@105.
79 Malibu "beater" w/junkyard 400 SBC, tweaked QJet 4bbl, finally a decent set of heads, a few other tricks. A maddening 13.000001 @ 108 on the motor with little traction. No nitrous runs with the new heads yet.
Grandma's old 78 Malibu (33K miles!) soon to have the powertrain from the 79 put in it.

"One of the last remaining QJet tuners on Planet Earth!"
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Old Nov 7, 2000 | 01:14 PM
  #3  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Damon, couldn't this just be a pull-off adjustment problem? 1900 is about right for the 1st step, when the choke is fully closed. As vacuum comes up after the engine is started, the pull-off should open the choke slightly and let the fast-idle cam drop so the choke idle speed screw is now on the 2nd step (you have to tap the accelerator to allow the idle speed to drop down). If the pull-off isn't opening the choke enough, the cam might not be dropping enough to get off that 1st step.

If you just back off the choke idle speed as it sits on the 1st step, you may allow the idle to drop too much as the choke starts to come off but the engine isn't up to operating temperature yet.

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82 Berlinetta, orig V-6 car. Rescued w/86 LG4/TH700R with all harnesses, sensors, ECM, etc. 2.73 open. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, exhaust, paint, etc.).
57 Bel Air, my 1st car. Currently 396 .030 over, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.
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Old Nov 7, 2000 | 10:22 PM
  #4  
Blown355Camaro's Avatar
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From: Nitrous Bottle
Ok, i kinda have this same problem, my car idles like at 2000 rpm in park , but in drive it goes to like 500 rpm!!

Do i just need a new freaking carb?!?!

ive got a 650 DP on my car, and it seems like its going to be too small..


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H00SiER DADDY
Supercharged 1985 Camaro TH350 9 bolt 3.23
1986 351 C4 Ford 9" Mustang Coupe
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