I've been having trouble with my 80 L82 idle swinging and inconsistent idle speed. I brought her in to have the carb rebuilt today, and it did not help much. The mechanic working on it has done 100s of these carbs. He thinks that I will need a new rebuilt one. Three questions, 1. If I get a carb with the same numbers, is there anything else I need to be concerned about matching number wise to stay original? 2. Is it worth having my carb sent to a carb shop to see if they can figure out whats wrong? Possible warped plate causing vacuum leak? 3. How rough does a normal 80 L82 idle.

When you mentioned the word vacuum it reminded me of a lesson I learned a long time ago.

I went thru what I thought was a carb problem with my 71 LT-1. Very rough idle and just a real bear to keep running. But once you got it off idle it ran great. The problem was not the Holley, that I can now rebuild behind my back blindfolded, but low vacuum signel.

The low vacuum signel, caused in my case by a worn timing chain, told the car 'the driver just put his foot into it, we need more gas'. Check your car for vacuum signel looking first for leaks.

I would also think that compaired to the late 60's cars with HiPo engines, an 80 L-82 should run (idle) like a kitten.

i agree it could be a vacuum leak. lots of vacuum lines on 80's check all the lines, loose carb, loose intake manifold, even power brake booster. try to hook a vacuum gauge up and see how much vacuum your holding at idle. spray carb cleaner around where you suspect leak might be and watch to see if the rmp changes. see if you can swap another carb from a good idling car and try it on yours

Thanks for the responses. Sounds like what you mentioned is close to what I am seeing on my vette. Idle problems but runs great at higher rpms.

I will start by buying a vacuum gauge and start checking some of the hoses. Is there a prefered/acceptable vacuum range at idle and at higher rpm?

|UPDATED|2/4/2003 9:29:59 PM|/UPDATED|

try this link for vacuum gauge readings. post what you come up with here. http://www.users.bigpond.com/ergoff/vac1.htm

Trying to give an answer about vacuum readings is very difficult to say the least . The manifold vacuum that can be read by the use of a vacuum gauge or a manometer is going to vary from vehicle to vehicle . Ignition timing , camshaft profile , carb adjustment , and the mechanical condition of the engine all contribute to the reading you will get . Generally speaking ,,,, this can get your butt in a sling .... 18/21 inches of vacuum is a good reading for an engine in good condition and tune . That is taking into consideration that you are not running a hot cam .
Trying to find a vacuum leak using a gauge is not very productive but it still remains an excellent tool to troubleshoot and tune the engine .

gman

BTW just to throw a little more info your way that might help, try this . Grasp the throttle lever of the car while the engine is not running ,,, hold the arm in the partially open position and attempt to move it front to rear . Look very carefully where the throttle shaft enters the carb base and see if you can see any SLIGHT PLAY OR MOVEMENT that would indicate either shaft or plate wear .This will raise havoc with your idle and generally cause you to say lottsa *&%$##@ words .

gman

4webbers is correct. Using a vacuum gauge will not help you find a leak but it is an excellent tool to troubleshoot and tune your engine.

|UPDATED|2/5/2003 6:12:09 PM|/UPDATED|

Hey guys, all of your sugestions sound good, and all should be tried before major $ is spent. I have a 79 L-82 and the cam was original, it would idle smooth with not much lope. I did replace it with a Comp Cams Cam and it now has a rough idle (I like it).
As for replaceing the carb with a rebuilt unit, I would go to Pep Boy's and get one, theirs are rebuilt by Holley ( Yes it is a Quadra Jet). I put one on my 79, no one could match up the #'s for a 79, ( it actually was for a 78 L-82). Keep your core, they will only give you about $25.00 for it. You should be able to replace the carb with a rebuilt one and keep your core for around $200.00 and one hour of labor. Then later if you want total originality you can send your original one out for a total rebuild to a carb specialist and spend about $400.00. I've had 0 problems with my rebuilt carb, it's been on my car now for around 5 years. Best of luck, hope you find your problem out.
70'S Guy

|UPDATED|2/6/2003 9:55:41 PM|/UPDATED|

Gman,
I tried what you said. I did not see any play where the throttle shaft enters the carb. Search continues....
Thanks for the advice.