I have a 1981 corolla with a 3TC all stock, my question is what will cause the carburetor to run too rich the engine?
at start up I can smell raw fuel and see the smoke out the exhaust pipe and after it reaches operating temp it stops smoking. also my MPG's are way down.
engine compression is good in all cylinders. I need some guidance from all 3TC gurus!
Also if carburetor requires rebuilding I would much rather upgrade! what are the pros and cons of a Weber carburetor?
also I live in "SMOG CHECK" capital of the US! California
I was right where you are now a few months ago. I rebuilt my carb and the thing was still too rich. It was perfect at idle, but when the RPMs went up so did the CO levels. I ended up finding a DFT 9A redline weber (smog legal) from ebay. They are super rare, but if you see one in the parts yard grab it and rebuild. The carb works the same way the other webers do. There is a CA executive order on the dmv or California Air Resource Board (CARB) which tells the smog shop that it is legal to replace the original. I am curious in what makes the stock carb richen up above idle because then I can fix 2 that I have now.
Check your plugs - if running rich they will likely be pretty fouled up and black. Clean them off or replace them and gap properly. Then check your timing. Double check for any clogged or leaking emissions lines. Even check the EGR (if still present) to see if it is stuck in any position.
After that, begin to check the carb for not enough air (due to blocks) or too much fuel in the float? The needle could be stuck causing excessive fuel into the float.
Where is your idle mixture screw set to? Is it all the way out?
Thanks for the replies guys!
I think I'm gonna remove the smog components and install a Weber! That being said out of the millions of vacuum hoses which ones do I keep and which do I remove?
Well now you are talking! lol If I remember correctly out of the million vac lines you keep 2. The ones for the Distributor advance. Sooo not that hard. Now they run rich and have to jet it cause they come for like a stage two engine build stock. Stock 3tc carbs came with 105 to 115 jets and can be made progressive. But thats another chapter. If you want performance try to go low for the primary jet like 125 to 130 cause you have a stock motor, right? . The air is the tricky part, the more air does not make it leaner it just means you can use more fuel. TRUST ME! LOL so go from 170 to 185. The secondary Im still working on to get right. The closest will be 140 gas and the same air as the primary or close to it. Remember the less air the less it will hesitate in upper RPM, the more air the more gas you have to put for it not to hesitate in upper RPMs. Its tricky to tune but you can use them on stock or rebuilt engines with upgrades. You should get headers, a good muffler and ignition system. Do not overlook this as it will give you more problems if not upgraded.
If you want performance try to go low for the primary jet like 125 to 130 cause you have a stock motor, right? . The air is the tricky part, the more air does not make it leaner it just means you can use more fuel. TRUST ME! LOL so go from 170 to 185. The secondary Im still working on to get right. The closest will be 140 gas and the same air as the primary or close to it. Remember the less air the less it will hesitate in upper RPM, the more air the more gas you have to put for it not to hesitate in upper RPMs. Its tricky to tune but you can use them on stock or rebuilt engines with upgrades. You should get headers, a good muffler and ignition system. Do not overlook this as it will give you more problems if not upgraded.