Weber 32/36 Carburetor Swap Guide for the 1987-90 Tercel (3e Engine)
My attempt to create the guide I wish I had when I started this project..
This is based on my research and experience doing the swap on an '89 Tercel EZ Federal model with 4-speed manual transmission. I attempted to retain as much of the original carb system as was beneficial. Total cost in parts was about $600 including all the odds and ends. Total cost in time was extensive, mostly because I didn't have this guide. Hope this helps the next lucky Weber swapper.
UPDATED 7/22/2010 with improvements to distributor advance connection instructions
UPDATED 8/22/2010 with improvements to throttle cable section
UPDATED 4/23/2011 - added vacuum diagram. DIAGRAM MAY DIFFER FROM SOME OF THE INSTRUCTIONS HERE. TRUST THE DIAGRAM MORE THAN THE PICTURES.
UPDATED 6/9/2011 - updated vacuum advance instructions to better match stock configuration
UPDATED 9/19/2011 added EBCV mounting and improved intake system. upgraded vacuum diagram
DISCLAIMER: I AM NOT A LICENSED MECHANIC. I PUT THIS TOGETHER BASED ON INSTRUCTIONS THAT CAME WITH THE PARTS, POSTS BY OTHER PEOPLE IN FORUMS, THE HAYNES MANUAL, AND BY DOING THE SWAP MYSELF.
Vacuum Delay Valve Colors:http://en.wikipedia.org/wiki/Vacuum_delay_valve
Info on OEM carburetor system - useful in understanding how all of the vacuum widgets work: http://repairnet.aircare.ca/document...yotatercel.pdf
VACUUM DIAGRAM for EGR and Distributor Advance:
WHAT YOU NEED:
-To not live in California. Redline claims the carb is not legal there.
-Redline Weber 32/36 Carburetor kit K751 (pre-jetted for the Tercel 3e) with adapter plate. I would and did buy new and not used.
-Redline Fuel Pressure Regulator Model: 31800.063
-OEM carburetor intake manifold gaskets, both upper and lower.
-Vacuum hose, the small diameter kind that connects most of the emissions control widgets on the OEM carb (no markings to identify size). Approx 25ft.
-1/4" low pressure fuel hose. Approx 15ft
-3/8" & 1/2" low pressure fuel hose. Approx 4ft of each.
-5/8" to 1/2" vacuum hose adapter and 1/2" breather filter
-Assorted hose clamps & black Zip-Ties (black ones are oil & heat resistant, other colors often aren't)
-1 1/2" long, 1/2" head hex-head steel bolts. I'm unsure of the thread pitch and bolt core size - I just took the bolts from the Weber kit to the parts store and had them measure it. You need 4 of these.
-1/2" (outer) diameter or smaller steel washers that will fit on the bolts. Get 8 of these.
-Typical assortment of mechanics tools: box-end wrenches, screwdrivers, wire snips, vacuum pump, etc.
-Digital voltage meter and tiny alligator clip jumper cables.
-Carburetor cleaner, PB Blaster
-Some of the widgets & such from the old carb.
-Haynes and/or Chiltons Manual for the car
-A new fuel filter
-New NGK spark plugs - I use "V-Power" type copper plugs
-New NGK or Bosch plug wires & distributor cap (they come together) and Bosch rotor button. NGK wires are better than OEM and highly recommended.
-Tachometer - I recommend installing one on your dash if you don't already have one.
-Lots of time
STEP ONE: REMOVE THE OLD CARB
Take the old carburetor and all of it's associated widgets off the car. You can follow the manual, but really you just take out the carb and everything that's mounted to it directly. The metal vacuum tube manifold monstrosity that's attached to the top of the intake manifold can go also, but put the bolts that hold it on back in - you may need them later.
-Keep the old carb and air cleaner around, you'll need some parts off them later. Be careful not to damage the plastic heat riser that sits between the carb and the intake manifold, you'll need it later also.
-Leave the charcoal canister and the vacuum switch mounted to the firewall above it where they are.
-Tie back any electrical connectors that used to go to the carb - Do not cut any plug ends off! You'll need some of them later!
-Remove the stud bolts that held the OEM carb onto the intake manifold.
-There will be two coolant hoses connected to the old carb. You need to connect them together. I just removed one and attached the end of the other one to where it was connected.
-Cut the throttle cable loose from the old carb as close to where it attaches to it as possible. There may be a removable bolt to detach it more cleanly, but I had to cut mine for some reason.
-Cap off any vacuum ports that are left open on the intake manifold.
STEP TWO: INSTALL THE NEW CARB TO THE INTAKE MANIFOLD
Depending on how assembled your carb was when it arrived, you may need to assemble the throttle linkage, springs, etc. Mine arrived completely put together and with instructions and I suspect most do.
You need to:
-Remove the adapter plate from the rest of the carb. The hex bolts you are going to use are too long to put through the adapter plate while it is attached.
-Put your washers in the recesses of the adapter plate's bottom. The washers act as spacers so that the bolt heads stick up high enough for you to tighten them. You may need only one washer per hole depending on how thick your washers are. You may have to sand the outside edge of the washers if they don't fit in the recesses.
-Put the bolts through the washers and hole of the adapter plate and then reattach the adapter plate to the rest of the carb.
-Clean the top and bottom surfaces of the heat riser from the old carb of any leftover gasket material. It is a plastic piece that has three vacuum hose connections and an electric plug. I had to use rubbing alcohol and a putty knife to get all of the old gasket off mine
-Clean the intake manifold surface of any leftover gasket material from the old carb. Same method as above, but don't use any metal tools that could scratch the surface.
-Put the upper carburetor gasket between the adapter plate of the Weber and the heat riser and thread the hex bolts through. Make sure the vacuum connections on the heat riser are pointing up towards the carb and not down. The upper gasket is the one with a circular hole in the middle. Do not use the gasket that came with the Weber - it is thinner than OEM gaskets.
-Put the lower gasket (the one with the circle squared off) on the bottom of the heat riser and thread the bolts through it. Set that on top of the intake manifold and tighten the bolts in - tighten bolts diagonally [opposing corners] to ensure a good seal.
-Plug in the heat riser's power connection. The plugs are all unique color and connector, so you can't plug it it the wrong place.
STEP THREE: ATTACH THE THROTTLE CABLE & ELECTRIC CHOKE
The throttle cable is pretty straightforward. You attach it to the Weber's bracket much like it was on the OEM carb's bracket.
-My Weber came assembled with the throttle cable on the passenger side, which is the opposite of the OEM carb layout. I ran the cable housing along the firewall tucked under and behind the brake power booster hose and it's bracket to keep it from flapping around. I recommend flipping the carb around on the adapter plate if yours comes assembled like mine did so that your throttle cable routing is more like the stock setup.
-Attach the end of the cable to the throttle lever per the instructions that came with the Weber. Make sure there is a little slack in the cable. Adjust the tension as needed so that you get full throttle just as the gas pedal hits the floor.
-For the choke, you can use the original choke wire, which will be a single-wire connector that used to go to the old carb that puts out 12v. Snip off the connector and crimp a flat female spade connector to it. Attach that to the Weber's electric choke connector, which looks like a little brass propeller.
STEP FOUR: ATTACH THE FUEL LINES AND FUEL PRESSURE REGULATOR
-I recommend changing all fuel hoses under the hood and replacing them with new ones. There's not many of them and you have to disconnect half of them to do this anyways.
-Replace the fuel filter if you haven't already. This will simplify troubleshooting and is cheap to do.
-The fuel pressure regulator is a very simple device with a diaphragm in it. There is a rounded bolt cap on one side that has an adjustment screw under it and a retaining nut around that to keep the screw from turning on it's own. Loosen the the retaining nut and Tighten the adjustment screw all the way in with a screwdriver (don't torque it down!) and then back it out two complete turns. This should give you a fuel pressure between 2-2.25PSI, which is where I have mine set. Tighten the bottom nut down to secure the setting and put the cap back nut. If you don't use a pressure regulator or if you set it to allow over 3PSI, the excess pressure can damage the carb over time. The stock fuel pump is rated for 3-6PSI which is too much for the Weber.
-The fuel pressure regulator documentation says to mount it horizontally and not to the engine or anything that vibrates. I could find no such place under my hood. I ended up mounting it vertically using the bracket that has the vacuum switch (the one above and to the left of the charcoal canister that I told you to leave in place earlier) and putting a piece of foam tape on the back to keep it from tapping against the firewall. I threaded the bracket ends through the mounting holes of the regulator and bent them back around it. It seems to work just fine this way. I zip-tied the vacuum switch that was there a nearby bundle of wires to secure it.
-Connect the fuel pressure regulator to the fuel pump where the old carb was attached. Make sure you connect the regulator in the right direction - the right side goes to the fuel pump if you are looking at the front of the regulator that has the adjustment screw on it. Connect the other side to the carb's large angled downward-pointing barb. Use hose clamps, of course.
STEP FIVE: ATTACH THE ESSENTIAL VACUUM SYSTEM
The vacuum advance is essential for the timing to be correct during acceleration. The PCV & breather is is essential for proper airflow in the crankcase. The charcoal canister must be connected or you will frequently smell gas in the car as it vents into the air under the hood.
-The PCV valve attaches the same way it did with the old carb. Run a 3/8" hose from the PCV to the heat riser's largest vacuum barb on the right side.
- The crankcase breather (the other port coming out of the top of the valve cover to the left of the PCV) and the charcoal canister's large hose on the left can be connected together with a T connector and then run to the hole in the bottom of the air cleaner.
-The middle, smaller port coming off the canister goes to the blue electronic vacuum switch, which then goes to the heat riser by using a T splitter on either the PCV or EBCV hose. It's not essential, but probably serves some purpose.
-The Air Suction System used to connect to the stock air cleaner, but I found no easy way to attach such a big hose to the Weber's air cleaner. I used 1/2" to 5/8" hose adapter and clamped a breather filter on it, then wedged it behind a wiring harness to keep it from flopping about. It's purpose is to let air into the exhaust system for the catalytic converter to utilize.
-The vacuum advance has two small vacuum hoses connect to two diaphragms under the distributor:
-The inner diaphragm (upper hose in this picture) connects to a T splitter. One side of the splitter goes to the the middle port of the orange BVSV on the back of the intake manifold and the other goes to a orange check valve (orange/back cylinder) and then to the cluster of three vacuum ports on the drivers side of the intake manifold. The black side of the check valve should connected to the manifold. The purpose of the BVSV and check valve is to give more timing advance to the engine until it warms up.
-The outer vacuum diaphragm (lower hose) connects to the right port on the front of the Weber carb itself. I added a red/white delay valve in line to keep the car from stalling by slowing the speed at which RPMs drop when letting off the throttle. The white side goes towards the source of vacuum.
-The inner port of the orange BVSV should be connected to the middle port of the heat riser between the carb and the intake manifold. The BVSV will open this port and thereby bypass the check valve once the engine has warmed up.
-The outer port of the BVSV should be capped (the bottom port of the HAC unit would normally connect here)
STEP SIX: ROUGH TUNING.
Now that that the new Weber carb is installed with all it's essential components, it's time to adjust it so the car starts and runs well enough to drive. Go ahead and replace your spark plugs and wires if you haven't already so that you are not tuning the engine to compensate for old plugs.
This is basically the same procedure outlined in the Redline manual:
-First back out the idle speed and fast idle speed screws as far as they go without falling out. They must not be touching the throttle linkage plates at their tips.
-Next, turn the idle mixture screw in all the way until it provides resistance, but don't torque it down. It just needs to touch bottom.
-Then back out the idle mix screw 2 full turns.
-Start the car and let it warm up until the radiator fan turns on. Adjust the idle speed screw until the car idles somewhere around 700RPM while it's warming up.
-Next, turn in the idle screw until the engine starts having trouble idling and acts like it's going to stall. Then back the screw out very, very slowly until the engine idles evenly.
-Then, adjust the idles speed screw until you get 800-900RPMs at idle. If your car as AC or an automatic transmission (or both) go more towards 900RPM. By spec, manual transmissions are supposed to idle @800RPM and automatics @850RPM, but there is no longer a throttle positioning system to raise RPM automatically when the AC turns on. If you already have your headlights, defroster and other stuff on, it may stall the car if your idle speed is set too low.
-Now, adjust the idle mix screw again until you get the steadiest possible idle.
-Go for a test drive and see how it runs. Make adjustments to the idle mix if necessary. If you smell gas while driving, you either didn't hook something up properly (like the charcoal canister or the fuel lines
) or the engine is running rich - in which case you should tighten the idle mix screw ever so slightly.
-Lastly, let the engine cool completely. If it's really hot where you live, you may have to do this in the morning when it's still cool outside. Get in the car with the engine off and stomp the gas pedal to the floor, then start the car. This activates the high idle (aka warm-up mode). The speed of this idle is controlled by the high idle speed screw behind the electric choke and the speed will increase as the engine warms up. Adjust the screw in until the car is idling above 2000RPM when the engine is hot enough for the radiator fan to turn on. If you bump the gas pedal or throttle cable, the high idle will disengage and the engine will idle normally, so don't do that until you're done adjusting the high idle or you have to wait for it to cool off again. The high idle will not engage when the engine is hot.
-You can now start driving the car again regularly, but I wouldn't go on any road trips until you've driven it around for awhile to make sure everything works ok. What you've done so far is just rough tuning. Your gas mileage may not be great and performance not as good as it can be, but the car should now be drive-able and probably already runs better than it did with the original carb.
STEP SEVEN: RECONNECTING THE EGR VALVE (OPTIONAL, DEPENDING ON LAWS WHERE YOU LIVE)
There are differing opinions about whether or not to connect the EGR valve and what effect it has on performance and gas mileage. Some areas have higher emissions standards that will require you to have a working EGR to pass inspection, others have no emissions requirements for cars this old. I connected my EGR because it worked once I cleaned it, I don't want to needlessly pollute the air, and the engine was designed to run with it functioning.
If you want or need to enable your EGR, here's how:
-First, test it to make sure it actually works. You can do this by applying vacuum to the port on top of it while the engine is running. If the EGR valve works, it will hold vacuum and the engine will stumble and possibly stall when you do this.
-If your EGR doesn't hold vacuum, replace it. If your EGR holds vacuum, but the engine doesn't stall, it probably just needs to be cleaned. You can clean your EGR valve by removing it and soaking the inner valve part of it with PB blaster and/or carburetor cleaner. Be careful not to get solvent on the gaskets unless you plan on replacing them and do not get it on or in the vacuum diaphragm on top of the EGR. Chisel away the black carbon deposits from inside it and from inside the hole in the intake manifold where it connects. Sometimes there is even carbon clogging the elbow-shaped pipe coming from the exhaust manifold into the other side of the EGR too. In my case, it was all clogged with carbon everywhere. It may take several hours of patient picking at the carbon and spraying chemicals to get rid of it all. Once you are done cleaning it, put it back on and test it again. If it still doesn't work, clean more or replace it with a new one.
-Connect the vacuum modulator in-line with the port on top of the EGR and the manifold vacuum source. The "Q" port goes to the top port of the EGR. The "P" port goes to the BVSV and ultimately the ported manifold vacuum on the Weber. The "R" port should be capped. The port on the bottom of the modulator connects to the port on the bottom of the EGR (which is capped in one of the above pictures).
-I recommend using the blue BVSV on the back of the engine towards the right side to prevent the EGR from activating before the engine warms up. You don't have to do this, but you should let the engine fully warm up before driving if you don't. This BVSV is a simple temperature controlled valve that closes the port to the atmosphere once the coolant temp is above 104*F so that vacuum is routed to the EGR. The vacuum hose from the Weber connects to the middle port of the BVSV and the EGR Modulator connects to the inner port. Leave the outer port uncapped or connect it to the air cleaner.
STEP EIGHT: FINE TUNING USING THE O2 SENSOR AND MULTIMETER
Now that everything is installed and working, it's time to fine tune your fuel/air mix. Pick a time to do this when the weather is as average as possible. Hot weather causes richer conditions (thin air) and cold weather causes leaner conditions (dense air) so you don't want to do this adjustment at either environmental extreme. You should do this at the same altitude you do most of your driving since that also affects air density. You adjust the fuel/air mixture using the same adjustment screw you did in step 6 earlier.
-Hook up your multimeter to the oxygen sensor and battery as shown in the pics above. Be mindful of the radiator fan when connecting the oxygen sensor to it - you don't want the cord getting caught in the fan!
-Start the car and let it warm up fully. The oxygen sensor will not give readings until the exhaust manifold is hot and you want to tune the mixture for a warmed up engine.
-At idle, you want the multimeter to register between 0.5v and 0.1v. Above 2500RPM it should read between 0.5v and 0.9v. Higher voltage = richer mixture. Ideal mixture is about 0.5v.
-If you don't get any voltage, you either have a loose connection somewhere or your O2 sensor is bad.
-If you are going to re-enable the computer's auto-adjustment of fuel/air mix (step nine below), you want it a little richer than the numbers above, because the computer can lean the mix but not enrich it. I set mine to about 0.45 at idle and 0.75 under throttle.
-Don't take readings while the radiator fan is running, the reading may change when it turns off.
-Go for a drive and make sure your settings work in the real world under load. You may have to adjust again to find the sweet spot for your car.
STEP NINE: ENABLING THE ECU TO ADJUST FUEL/AIR MIXTURE (OPTIONAL, RECOMMENDED)
This step will allow the computer to lean out the fuel/air mixture on-the-fly based on the readings from the oxygen sensor. This system is designed to improve fuel economy and reduce emissions by keeping the mixture as close to perfect as possible. Three widgets must all be plugged in for this system to activate: The oxygen sensor, the Electronic Bleed Control Valve (EBCV), and vacuum sensing switch that originally mounted above the charcoal canister. The system will not operate if any one of them is unplugged. This system does not exist on Canadian '87 Tercels, but should be present on all other Tercels with a 3e motor.
Here's the parts:
This is the EBCV (Electronic Bleed Control Valve). It lets extra air into the intake manifold to lean out the fuel/air mix.
-It was originally attached to the underside of the stock air cleaner on the passenger side and is labeled. The Intake side of the EBCV has a rubber gasket and three phillips-head screws that hold it onto the stock air cleaner.
-I couldn't find a way to mount this to the Weber air cleaner or the K&N air filter I ultimately added, so I had to get creative. I cut a hole in the side of a large 5/8" heater hose and screwed, glued and taped the EBCV on over the hole. I plugged one end of the hose with a bolt and hose clamp. The other end I attached a 5/8" to 1/2" coupling and a breather filter to the coupling. The end result is a bit funny looking but works better than the rag in the picture above.
-Find the electrical connector that went to it on the passenger side of the engine and plug it in. The connector is unique and impossible to plug in the wrong place.
-Connect a vacuum hose to the port and run it to the leftmost port on the heat riser.
-This is the vacuum sensing switch and associated BVSV. All the switch does is sense vacuum. If it doesn't sense vacuum, it won't let the computer to go into closed loop and start using the EBCV to adjust the mixture. There is an in-line vacuum limiting valve between this switch and the BVSV, but it's not in this picture. There's a picture of it in it's correct configuration back in Step 5.
-The BVSV supplies vacuum to it from the middle port only if the engine coolant is above 43*F. Basically, this turns off the EBCV when the engine is really cold. It's optional to connect, but I figure there's probably some reason Toyota didn't want the EBCV activating below 43*F, so I connected it.
-The outermost port goes to manifold vacuum.
-The innermost port I have capped off. It used to go to a vacuum-sensing-valve that connected to the original carb. It's purpose was to control air bleeds when the engine was below 43*F. The one from my old carb didn't work, so I didn't investigate further.
-Make sure you have the oxygen sensor plugged in.
-Test if the EBCV is activating and pulling in air. Do this by starting the engine and letting it warm up. The EBCV won't pull any noticeable amount of air at idle, but when you pull on the throttle cable it should start sucking in air. Put your hand over it's intake and see if it creates suction. If it doesn't, you may need to adjust the idle mixture to be a little richer - the EBCV won't suck air when the engine is running lean.
-Take it for a test drive, but I would avoid those risky right and left-hand turns when there's oncoming traffic until you're sure the car will take off normally when you step on the gas suddenly. I had to make a few slight adjustments to the idle mixture to get the acceleration behavior just right. I think the ECU expects the carb to be running rich by a specified amount and it works well once you find the magic setting.
STEP TEN: IMPROVED INTAKE SYSTEM (OPTIONAL - IMPROVES PERFORMANCE)
The Weber's stock air cleaner leaves a lot to be desired. It has too much air restriction due to the small filter; it isn't enclosed to completely keep in fumes from the evap system; and it pulls in air from what is probably the hottest area under the hood.
-Here is the solution I came up with for adding a pre-heater hose, better air cleaner and filter, and colder air intake. After this upgrade, I immediately noticed an increase in power especially at higher RPM. It also makes the carb sound quieter and less fart-like.This cost me about $260 to do - $110 for the snorkel and $130 for the K&N intake kit, plus shipping:
-This is basically a Redline Weber Snorkel model 99010.357 connected to a K&N Apollo Cold Air Intake. The two connect without the purchase of any additional parts. The snorkel attaches to the carb with 4 bolts the same way as the original air cleaner. If you don't want/need a pre-heater hose, then you don't need the junction piece.
-The 1/2" hose that used to connect to the Weber air cleaner in the earlier steps can be connected to the port on the K&N, but you'll need a longer piece of it to reach.
-For the pre-heater connection I used a ABS (black) plumbing pipe junction "cleanout trap" with a 2" straight through size and a 1.5" port coming off the side. DO NOT USE PVC - IT WILL RELEASE TOXIC FUMES AND MAY MELT! The pre-heater hose connection on my exhaust manifold had rusted off, so I had to have a pipe welded to it. Since it was the same price, I had the welder just run piece of exhaust pipe to the junction. You should be able to just run a normal pre-heater hose to the junction unless you have similar rust issues.
If all went well, you now have a better than new carburetion system on your Tercel.