Stock vs. Weber

[SirFoxx]

I've only had a Weber on my car and I've never had any carb problems. My gas mileage isn't great though, getting about 18 mpg but that's probably due to my 27 inch tires.

18 mpg would be terrible. 4.11 gearing should get high 20s, 3.73 gearing should get low 30s. Are you taking the size difference between stock and your tires into account when calculating your mileage, ie adding 10% or whatever to the miles traveled?

the only time ive gotten high 20s was during a road trip. stock carb should net ~23-25, weber 21-23 from personal experience.

[Cadendoo22]

I've only had a Weber on my car and I've never had any carb problems. My gas mileage isn't great though, getting about 18 mpg but that's probably due to my 27 inch tires.

18 mpg would be terrible. 4.11 gearing should get high 20s, 3.73 gearing should get low 30s. Are you taking the size difference between stock and your tires into account when calculating your mileage, ie adding 10% or whatever to the miles traveled?

Yes I am, I'm also running a 4AC so I imagine the mileage is a little worse on those. I also drive with a flat foot but I think my ignition timing is probably the biggest contribution to my gas mileage as I haven't touched it at all. I need to set it to 10 BTDC

[xirdneh]

Stock carb keeps rpms up while shifting for less gear grind
Stock carb gets 30 mpg for all around driving (stock tire size)of

[SR5]

I'm gonna dig this thread up. I'm new here. Greetings from Washington State. I want to know if anyone has desmogged a stock Aisan carburetor.

I got my 1982 Corolla-Tercel SR5 for the price of pulling it out of someone's yard. After throwing a small amount of time and money at it, I have a fun little car. One thing I did was remove and plug a bunch of vacuum lines and ports. I got rid of all the EGR hardware, and anything else that seemed unnecessary. I even deleted the catalytic converter after it came apart on a road trip. My intent was to get down to a basic engine. From experience I know those vacuum lines can be a problem, especially when they get old and start to crack. The rubber diaphragms can cause similar problems. I'm old-school, and obviously, don't have to pass emissions.

But the carburetor...
Temporarily, I just plugged all the ports that I wasn't using and ran it. It doesn't run bad once it's going, but it's hard starting. I can see that the accelerator pump isn't working, and neither is the choke. I like Webers. They are simple, and I had one on an Opel GT years ago, and never had a problem with it. I see Holly also sells a carb to fit this engine. But I'd like to just rebuild the Aisan carb, minus any smog crap, and keep the stock air cleaner. Has anyone done this? What do I HAVE to keep, and what can I get rid of? Will it need re-jetting? Are jets available?

[dlb]

Welcome, SR5. This forum isn't as active as it used to be so I'm not confident you will find anyone here with experience completely removing all the emissions stuff from the stock carb. I know that some other non-current users here did so in the past though so I recommend searching here to find those threads.

Weber's work fine but they are not without their own problems, in my experience. Mine used to ice up in some winter driving conditions. Hood clearance was another issue. And they're expensive. Plus they need a fuel pressure regulator and gauge in Tercels because the fuel pump puts out higher PSI than Weber's want.

Personally I find the stock emissions and vacuum stuff to be pretty reliable so I think it's easier to make sure it's all connected properly and not leaking than to try to figure out how to make it work well without that stuff. To each their own though.

[Mark]

It will be almost impossible to start when it's cold with the choke breaker diaphragm vacuum hose disabled. That system opens the choke slightly on startup. If it doesn't, there isn't enough air for it to idle. The vacuum advance on the distributor needs to remain hooked up, otherwise the engine will run inefficiently. Basically, many of those vacuum components aren't just to do with emissions control, but are there to make the carb operate correctly in a variety of conditions.

[Paul]

The stock carb relies on "computer" controlled air bleeds (EBCV) to maintain optimal mixture based on oxygen sensor signal. So the default rich mixture is leaned out based on conditions. The advantage to retaining the stock controls is compensation for temperature and altitude. If you study the FSM and get everything working correctly, it's fairly reliable. I think frustration with these controls drive many to try the Weber route. I prefer to keep it stock.
Edit: EBCV does the air bleeds

[Mark]

I think many Tercels didn't have that oxygen sensor feedback carb system. Mine does (1984 Canada automatic), but it's hard to get parts for it since most Tercels didn't seem to be fitted with that system. Maybe the California models had it? I don't think any 1st gen (like the poster's 1982) Tercels had that system yet.

[Paul]

My bad... I was thinking T4WD. My '83 had the carburetor feedback system and my '88 has it too. FSM says USA Vehicles and Canada 3A-C Engine 4-Speed & Wagon A/T.
I found this diagram that might be helpful to the owner of the '82 Corolla Tercel. I see it uses a mixture control valve, which just lets air into the intake manifold during deceleration.

MA4054G.jpg

[SR5]

Welcome, SR5. This forum isn't as active as it used to be so I'm not confident you will find anyone here with experience completely removing all the emissions stuff from the stock carb. I know that some other non-current users here did so in the past though so I recommend searching here to find those threads.

Weber's work fine but they are not without their own problems, in my experience. Mine used to ice up in some winter driving conditions. Hood clearance was another issue. And they're expensive. Plus they need a fuel pressure regulator and gauge in Tercels because the fuel pump puts out higher PSI than Weber's want.

Personally I find the stock emissions and vacuum stuff to be pretty reliable so I think it's easier to make sure it's all connected properly and not leaking than to try to figure out how to make it work well without that stuff. To each their own though.

Yeah, I was wondering if there was much going on with these old cars anymore. It's a little late for me to stick with the emission stuff. I've already yanked it all off. Might have been a mistake, but it's what I'm used to with other cars. I can usually get a simple carbed engine to run well, but I didn't know what to do with all those vacuum systems. Thanks for the reply.

[SR5]

It will be almost impossible to start when it's cold with the choke breaker diaphragm vacuum hose disabled. That system opens the choke slightly on startup. If it doesn't, there isn't enough air for it to idle. The vacuum advance on the distributor needs to remain hooked up, otherwise the engine will run inefficiently. Basically, many of those vacuum components aren't just to do with emissions control, but are there to make the carb operate correctly in a variety of conditions.

I have kind of gathered this. Some of the carb stuff will need to be hooked back up. And I think that choke breaker diaphragm is fed from a coolant temp switch that I already pulled and tossed. At the time, I was definitely going with a weber. I'll have to figure something out for that.

[SR5]

The stock carb relies on "computer" controlled air bleeds (EBCV) to maintain optimal mixture based on oxygen sensor signal. So the default rich mixture is leaned out based on conditions. The advantage to retaining the stock controls is compensation for temperature and altitude. If you study the FSM and get everything working correctly, it's fairly reliable. I think frustration with these controls drive many to try the Weber route. I prefer to keep it stock.
Edit: EBCV does the air bleeds

I have a 1982 fwd version. I think it was before there was an O2 sensor on it. I don't think this car has any computer/diagnostics on it whatsoever. I haven't seen an O2 sensor in the pipe...?

[SR5]

I think many Tercels didn't have that oxygen sensor feedback carb system. Mine does (1984 Canada automatic), but it's hard to get parts for it since most Tercels didn't seem to be fitted with that system. Maybe the California models had it? I don't think any 1st gen (like the poster's 1982) Tercels had that system yet.

Ah, yes, this. Even though this was originally a CA car.

[SR5]

My bad... I was thinking T4WD. My '83 had the carburetor feedback system and my '88 has it too. FSM says USA Vehicles and Canada 3A-C Engine 4-Speed & Wagon A/T.
I found this diagram that might be helpful to the owner of the '82 Corolla Tercel. I see it uses a mixture control valve, which just lets air into the intake manifold during deceleration. MA4054G.jpg

Oh boy, yeah, this reminds me of why I deleted all that stuff. For one, I just don't understand how it all works. And two, a crack in just one vacuum hose and you have a vacuum leak that seems like a nightmare to find. I don't actually see in the diagram where the mixture control valve is.

[SR5]

Here's a pic of the little beast. It looks pretty straight in the picture. It's not. It has plenty of dents.

IMG_20240201_154641[1].jpg