: Carbeurator Problem?

09-10-08, 11:20 PM
Was looking through Craigslist today, for sh*ts and giggles, and came across this. http://chicago.craigslist.org/nwi/cto/828488177.html

For the price, it would make a fantastic winter car for me. I have some experience with carburetors, but not too much (mostly small engines). Is it possible that the carb is simply tuned wrong or is there something else that could be the cause of the problem? Why would it have an O2 sensor if it is carbureted? This is the 5.0 Chevy engine right?


09-11-08, 02:12 AM
I don't know what the problem is, but I think that those Quadrajet carbs were basically a concoction engineered by folks who didn't really wanna give over to the whole fuel-injection thing.

And that car has the Olds 5.0L 307cui.
My 1983 Olds Delta 88 has the 307, and yes it does have function for an 02 sensor. I know because mine was causing a rich mixture and burnt up the cat.


09-11-08, 11:37 AM
Can the Quadrajets be adjusted for fuel air mixture? To me it sounds as though when the choke is on it runs fine but the normal running mixture is wrong.

09-11-08, 12:52 PM
The Quadrajet is an excellent carb. It was first designed and used in the late 1960s, and has been built in many varieties (electronic, larger CFM, etc). It has small primaries for good mileage, and big secondaries for great full throttle power on acceleration and passing. Lots of older guys just say "put a Holley on it", but a well-tuned Quad will perform as well while delivering better mileage.

The mix screws on an 80s quad are set from the factory, and it shouldn't be necessary to adjust them if everything else is playing nice.

As for the car in the ad, it looks like a great deal. 500 or 600 will likely get the deal done. It shouldn't be too much trouble to figure out what is wrong with it once you have it. You may be able to figure out what is wrong just from checking the car out. Hopefully, you can start it when it is cold, and observe the carb without the aircleaner. Watch the choke. See if it is closed. Take it out for a drive to get it up to temp, and then check the choke to see if it is fully open. If it is still closed, you have found at least part of the problem. If it has been like that for a while, the cat is likely bad as well from the rich mixture. It will have to be changed. Other possible causes could be improper timing, low idle speed, clogged fuel filter. Cars are pretty easy to get to stay running. Fuel, air, spark, and somewhere for the exhaust to go. Once you can start crossing things off the list, then it will be pretty easy to get it to work.

09-11-08, 12:59 PM
If the cat is clogged, I am just gonna hack it off. Here in IL, cars without OBD-II do not need to go for emissions testing.