I need some carburetor advice - Toyota Nation Forum : Toyota Car and Truck Forums

sapoverde · 02-01-2010, 11:09 PM

I have a 1988 Corolla Wagon 4AF that needs carburetor work. It stalls at idle once I've been driving it for a while, once it's warmed up. I've done a tune up, checked the fuel pump, and sprayed a carb cleaner. Still stalling. It's even difficult to get it started again if I shut it off; I have to give it a lot of gas. It doesn't go back to normal until it's been turned off for a while and gets cold. It's not overheating. Also, it's always difficult to turn off; lot of coughing and choking like it doesn't want to turn off.

Not sure if the choke is getting stuck, if it's a vacuum leak, etc. What should I do? It's a very complex carb with tons of vacuum hoses, so to troubleshoot one component at a time could take forever. I want to keep this car for a long time, so I'm willing to do whatever it takes to fix it and make it run the way it should.

Should I buy a new carb? Should I upgrade the carb to a Weber? Do new carbs come with the A/F mixture already set like the factory carbs? Are Webers hard to pass emissions? Please help.

sapoverde · 02-01-2010, 11:39 PM

p.s. once it's warm, it smells like it's running rich; heavy gas smell from the exhaust once it's warmed up and been driven a while.

***SCT*** · 02-02-2010, 08:00 AM

Idle setting may be too low. There should be a small white knob the size of a dime on the driver side of the carb facing towards the back. Turn clockwise to increase it, but do it by small turns (quarter turns).

Fuel mixture can also be too rich and also timing, but try the idle adjustment first. It may at least keep it running at idle.

Also with the heavy odor of gas, your carb may be fine. However, it may be a or two cylinder misfiring OR some other problem. I had cases before where when it's cold, leaks and what not are sealed so everything runs like normal. Then when heated, the leak opens back up so the problems are back.

Donald · 02-02-2010, 12:18 PM

Check your float setting.

It is brobably letting the bowl get too full, and when parked hot, the fuel in the bowl expands and over flows into the intake. This causes flooding when you are trying to start. That create the need to press the pedal and open the throttle to let more air in, so the mixture leans out enough to start.

As the over flowing fuel vaporises out of the hot intake it can cause a fuel smell in the engine compartment also.

retiredat44 · 02-02-2010, 10:43 PM

how many miles are on the carb..
be careful if trying to adjust with a screw driver, ss when you start changing settings, it is very difficult to put
the carb settings back in spec..

It is best to have the tune-up done by a good mechanic and computer...

It is best to have a carb rebuilt if there is lots of mileage and wear..

IMHO

sapoverde · 02-03-2010, 12:39 AM

Thanks for all the feedback. The carb has 134k miles on it. I agree that the quickest and most efficient solution would be for a certified toyota mechanic to diagnose and repair it, preferably one with ae92 experience. Bottom line is that it's flooding gas somehow. Where and how is beyond me. Could be the float. Don't think it's the idle.

Any recommendations on a new carb? Anyone know anything about the Weber?

retiredat44 · 02-03-2010, 01:23 AM

you don't need a Toyota mechanic... you just need a carb shop to either replace it, or rebuild it..

a rebuild kit is only about $20.00
a rebuilt carb is probably a few hundred $$..

I rebuilt mine for $20, a few years back.. it had 200,000 miles on it..
I definitely recommend a pro does the work..
I had many years of experience, but I also cut corners...
but it came out pretty good, but I did not have the best tools for it.. and didn't have a good clean tank, and also didn't mess with the float,,, as the hardest part is resetting a float, so I kept the factory settings...
just replaced all the parts that came in the kit..

I only have stock parts on the car..

Donald · 02-03-2010, 12:34 PM

Quote:

Originally Posted by sapoverde

Bottom line is that it's flooding gas somehow. Where and how is beyond me. Could be the float. Don't think it's the idle.

The float.

retiredat44 · 02-03-2010, 03:24 PM

the needle jet valve which the pin is pushed by the float can wear out, even when the float is set properly.. as the end of the pin wears and no longer seals properly when in the closed position...

so when that is replaced is solves a lot of problems, and no need to re-adjust the float..

but since you get all the new parts replace all the parts.. and do a great job with carb cleaner to get all the crap out of the passages..