weber carb questions

gatemaster · Post by **gatemaster** » Sun Sep 24, 2006 1:45 pm

I just found this forum yesterday while seaching google for weber carbs. I had no idea there would be a forum on this car but am very grateful for it. I have read most of the topics in here but still feel unsure about the weber switch. I have an 84 3ac 5 speed sr5 4wd tercel. I have had 2 tercels the other was a budget sedan with the same engine. I have had the same problem with the carb on both cars. Poor gas milage, poor performance, erratic acceration and idle, and stalling. I have also had a problem on both cars with the car dying on takeoff after having drove it somewhere then turning it off , like to go in a store then coming out to leave and it leaves me in the street, like it had vapor lock. I reamidy this by letting it idle for a few minutes first before driving away. I did find that the cold start heat valve between the exhaust and intake was getting stuck contributing to the problem. In general I think any stock carb is mostly junk. I have a lot of experience rebuilding various engines and carbs but have never ran into so many problems as this car has . Last year it passed emissions easily, then it sat for about 6 months before I started driving it again, now this year it failed very baddly even though it is more drivable than before.
Based on experience I would expect this car to have a little more power and fuel economy than it does but nothing seems to make any difference.
I have already been through all the vacuum lines and other possible causes
that I know of. I forgot to mention that it has a rebuilt engine, bore and hone and 3 angle vavle job and head shaved.
The only way I see that the mixture module w/ the o2 sensor could control gas/air mixture would be by using the 2 solenoids on the carb but that seems to be not very precise. So I figured that by the time I replace all
of this emissions stuff I could have bought a weber. The question is that I see mixed opinions on the weber carb performance, fuel economy, and possible emissions problems. I assume that like a holly the weber is easy to work on and has many possible jetting configurations to find an ideal
balance between the different expectations from the carb. The stock carb on this vehicle has been rebuilt twice with the same results. Any feed back from personel experience or links like reviews would be appreciated.
Weber claims something like 10 to 20% improvement on power and fuel economy. Also all the sites that sell webers say it uses the original air filter
but shows a custom filter in the kit. In a post in this forum someone said to get the low profile air filter, coild someone clarify this for me. thanks

gatemaster · Post by **gatemaster** » Sun Sep 24, 2006 5:27 pm

I guess what I'm asking is this a good investment? Will the weber get passed emissions? Our laws here in NM only require that cat converter, air injection in other words original equipment is checked but not any o2 sensor or other vacuum crap, besides the gasses check obviously. It seems that the weber 32/36 is even a little too much for this engine, is that correct? Does it come jetted correctly for the 3ac or does it need to be jetted down a bit?

gatemaster · Post by **gatemaster** » Mon Sep 25, 2006 12:32 am

i'll find out soon I ordered the kit k740 tonight for $365

takza · Post by **takza** » Mon Sep 25, 2006 3:44 am

You are talking to yourself? Welcome...to Tercel Island.

Typrus · Post by **Typrus** » Mon Sep 25, 2006 9:03 pm

Some days we're not incredibly active. Sorry I couldn't have been on for you.
My question falls on emissions. But for me, it doesn't matter as before I need my next check, Northern Colorado will kill its Emissions program. I just need the $$$

I was going to say rebuild....

That sounds like vapor lock to me. It happens to me a lot on hot days. Less since I put the dual-core radiator on though. Check your spark plugs. Decked (shaved) how much? according to various programs, .018 will yield 9.5:1 (stock is 9:1) and .034 in will yield 10:1. If you are running a lower octane, try a level up. I find I run best (and I'm essentially stock) on mid-grade. Runs cooler, gets a bit better fuel economy, and my responsiveness bumps up a bit. Premium gets me no further though. In your case, try Premium fuel from a good supplier. No cheap fuel. I personally consistantly get about 3 mpg better on Valero (Diamond Shamrock) fuels versus King Soopers. The .04/gal difference pays back pretty quick I'd say. Even a 10 cent difference is paid back.

How long ago was it rebuilt? I recommend a Sea-Foam treatment.

Hows your distributer doing? If you are getting weak spark, things might be messed up.

What spark plugs you use? If its Champion or some USA brand, kick them out and fast. Denso or NGK are the ONLY way to go on these engines, IMHO. I'd recommend a good U-Channel or Iridium. But play with some standard ones to find the right temp range.
Do you know how to read spark plugs? No, I'm serious. And I don't mean the lettering, I mean the conditional analysis type of read.

What oil do you use? What brand oil filter? Grade? Synthetic or standard? Any additives?

Any fuel additives at all?

I want all the info....

BTW, the Sea-Foam Treatment is located under Repair Guides, written by yours truly.

gatemaster · Post by **gatemaster** » Mon Sep 25, 2006 9:04 pm

people do that sometimes when no one else is around. glad to be here thanks

Typrus · Post by **Typrus** » Mon Sep 25, 2006 9:14 pm

Think you missed mine >.<

gatemaster · Post by **gatemaster** » Mon Sep 25, 2006 10:27 pm

yes I missed yours. The engine has 10k on it at most. just tried boshe platinum x2. I have tried many things nothing makes any difference.
the wierd thing though is that after the 3 angle valve job I could not get rid of loud tapping, it sounded like a diesel. I tried hot and cold settings finally
I reduced the valve lash but I don't remember how much guess maybe 1 or 2 thousands. the coil is in the dist. I was thinking of installing an older
dist and using an external high volt model. I haven't seen any of the plugs you mentioned here in NM. The body (red) and interior is in excellant condition and looks like a deluxe model for its time. It even has an electric sunroof that works. I am hoping that the weber w/ fuel regulator will yield the results I am looking for. I wondered about a slightly better cam as the stock one seems to be really weak. I also was thinking about some port clean up and combustion chamber work around the valves, I have the tools for that and the knowledge of what can be done by the home mechanic while not ruining it. I think some headers would help a lot but they don't seem to be available and I don't want to try and build custom ones. I was anxious and couldn't wait more than a day for feed back so I went ahead and hoped for the best on the weber. An electric fuel pump would probably solve any vapor lock issues. Head was milled just enough to make it flat.
I can't remmember if the pistons were flat tops or if they had valve reliefs.
I've been using valvoline non syn oil but I am thinking of switching to synthetic. I tried fuel additives? I can read sparkplugs, the car is running real rich, but the stock carb has limited adjustments. I like this car and would like to enjoy it for a few hundred thousand miles. Thanks for your interest.

takza · Post by **takza** » Tue Sep 26, 2006 5:44 am

gatemaster wrote:yes I missed yours. The engine has 10k on it at most. just tried boshe platinum x2. I have tried many things nothing makes any difference.
the wierd thing though is that after the 3 angle valve job I could not get rid of loud tapping, it sounded like a diesel.

Bosch plugs will cause a ping. NGK V power or regular? Cooler plug?

I experienced this for maybe 30 seconds sitting in traffic on a hot day using fuel heat. Sounded just like a diesel and it probably was dieseling. Went away as soon as I got going.

I'd say you are running too high of a compression ratio...plus carbon buildup from the rich mixture? Do an ATF/water carbon clean? Might try Shell V type premium?

3 oz acetone plus 3 oz xylol per 10 gallons might help? Both raise octane. Adding 0.25 oz Torco GP7 2 cycle oil (per 10 G) can help too.

The O2/ECU finetunes the mix using the 1 or 2 valves on the pass fender to add some air to the gas to lean it. I'd check all your vac lines.

Try adjusting the timing on a backroad...adjusting it to where you just see some light ping under 1/2 throttle in 5th from 1200 up to 1700 RPM? Or set it more retarded than this?

gatemaster · Post by **gatemaster** » Tue Sep 26, 2006 10:30 pm

I have been suspecting a vacuum leak but can't hear any, also I replaced all the vacuum lines so it must be a diaphram or some other device. The weber is scheduled for delivery on thursday so I will get that on this weekend. I will try advancing the timing using plus gas till it almost pings and then I will try reg gas and see what the difference in timing is.

Typrus · Post by **Typrus** » Thu Sep 28, 2006 10:04 am

I hate regular gas... Its eeeeeeeevil.....

Don't be cheap... premium or midgrade.........

gatemaster · Post by **gatemaster** » Thu Sep 28, 2006 6:15 pm

The other night I was at costco with half a tank of regular gas in the car and thought I would top it off with premium which would equal a full tank of plus.
I don't know if it is coincidence that something unrelated went wrong at this time but ever since the car has run like crap, so I'm parking it. It was sputtering and overheating, no power, go figure. The weber came today so I am anxious to check it out. I am also going to install a dual tube all metal radiator I have from another tercel.

gatemaster · Post by **gatemaster** » Sat Sep 30, 2006 11:54 am

I haven't had time to install the weber yet but got curious and pulled the bosch plugs the kind with 2 side electrodes. The are only a week old and the center electrode on all 4 plugs is burnt off and 1 plug the ceramic was melted. No wonder the car ran like crap, a wonder it ran at all. I see a condensor on the side of the distributor but have never changed it. Anyone know what causes electrodes to burn off?

keith · Post by **keith** » Sat Sep 30, 2006 3:24 pm

Hi; I'm new here too, just discovered it. Don't do the all metal radiator, I made that mistake myself. It will eat up the cylinder head. The all metal ones are made in the Philippines out of some unknown copper looking alloy. This alloy will set up galvanic corrosion with the aluminum in your cylinder head and the aluminum will migrate and coat the inside of the radiator, Then the head will crack. Almost all replacement radiators are dual core now, get the aluminum core with the plastic tanks.

86 SR5 4WD 312,000 miles.

Gasoline Fumes · Post by **Gasoline Fumes** » Sat Sep 30, 2006 10:46 pm

gatemaster wrote:I haven't had time to install the weber yet but got curious and pulled the bosch plugs the kind with 2 side electrodes. The are only a week old and the center electrode on all 4 plugs is burnt off and 1 plug the ceramic was melted. No wonder the car ran like crap, a wonder it ran at all. I see a condensor on the side of the distributor but have never changed it. Anyone know what causes electrodes to burn off?

I had a similar experience with the normal Bosch Platinums in a Honda. The center electrodes just didn't last. I'll never buy a Bosch plug again.