1987 weber carb install runs rough/dies after hot start

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dyork
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My tercel:: 1987 tercel wagon. weber carb. roof rack.

1987 weber carb install runs rough/dies after hot start

Post by dyork »

hey guys! long time lurker here. am super thankful for all the info i have found over the years here. I have an 87 tercel wagon I picked up earlier this year. was 100% stock when I got it and ran ok but was soooo slow. the previous owner didn't do much in terms of figuring out why. when I purchased it I drove it home 100 miles. about halfway through the car started sputtering and I had to pump the gas pedal to keep it running for about 2 min. after that it ran fine the rest of the ride. I chalked it up as carb issues and continued to drive it until I could get a weber from Yotashop.com. got the weber installed and everything seemed to be working fine. a few weeks later it would intermittently run odd like it was running out of fuel. after closer inspection I noticed air in my fuel filter. i proceeded to replace the fuel lines with all new ones. I even pulled the straw out of the tank to inspect but all looks good. it seems to only have issues when I drive it for 30 min or more then shut it off for a time and then restart. it acts like it's not getting fuel but the pump is working (electric) and I put a 4 psi regulator inline also. im not sure where to go from here to what to check. the car starts and runs great when cold and will run all day long until I shut it off and turn it back on. the choke is working correct as well. thanks!
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: 1987 weber carb install runs rough/dies after hot start

Post by dlb »

Sounds like it could be vapor lock (which I admit I don't really understand) but it also sounds like the mechanical advance in the distributor could be stuck. Remove the distributor cap and twist the rotor each direction. I can't remember which is which now but one way it should not move, while the other way it should rotate a bit and snap back if you let go of it. If it doesn't do that, you need to disassemble the distributor, clean out the gummy old grease that is causing the mechanical advance to stick, and re-grease it.
dyork
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My tercel:: 1987 tercel wagon. weber carb. roof rack.

Re: 1987 weber carb install runs rough/dies after hot start

Post by dyork »

thanks! will try that tonight!
dyork
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My tercel:: 1987 tercel wagon. weber carb. roof rack.

Re: 1987 weber carb install runs rough/dies after hot start

Post by dyork »

Update: I pulled the dist cap and the rotor doesn’t budge either direction
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: 1987 weber carb install runs rough/dies after hot start

Post by dlb »

I looked it up and it should be able to rotate counterclockwise a little bit.

What I found when I ran into this was that the rotor seemed stuck but while driving, it would slowly make rotate one way or the other until the car started driving lousy under varying conditions (depending on how far advanced the timing was stuck). So note the position of the rotor, remove the distributor from the engine, and tear it down. There are some small pieces in there so be sure to work in a clean space in case something bounces off.

Alternately, if you have a known good distributor you could just swap that in. Then you can fix the bad dizzy at your leisure and then keep it as a spare. It's been a while but I think it took me 1-2 hrs to re-grease a dizzy. Depends on how gummy and hard the old grease is to get out.
dyork
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My tercel:: 1987 tercel wagon. weber carb. roof rack.

Re: 1987 weber carb install runs rough/dies after hot start

Post by dyork »

I will prob try to find a good used one since she is currently my daily driver. Thanks for the info I will keep you updated!
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: 1987 weber carb install runs rough/dies after hot start

Post by dlb »

Very good. When you install the new dizzy, make sure to disconnect and plug the vac advance hoses and set the timing. Stock is 5 degrees BTDC, most here prefer 10 degrees BTDC. Reconnect the vac advance hoses afterward.
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Petros
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Re: 1987 weber carb install runs rough/dies after hot start

Post by Petros »

if it is only difficult to start it when it is very warm, vapor lock could the issue. or it could be a partly blocked fuel filter, those are cheap to replace, and if yours in not recetnly changed you might change it anyway.

Vapor lock is where part of the fuel line gets hot from passing over the engine or exhaust manifold and it causes the fuel to vaporize, creating a gas bubble in the fuel line, effectively blocking it off until it cools down. the current ethanol fuel blend is easy to vaporize (EFI cars are not so much affected by it). when it is running, cooler fuel from the tank is getting passed through the line and prevents the vaporizing, it is only after you shut it down that the fuel line gets "heat soaked", and it vaporizes. it is not common this time of year, usually it only occurs in the hot time of year, in summer. though it is possible.

a quick way to check for that, if it will not start, lift to hood and spray some water over the fuel line where it passes over the exhaust manifold, cooling the line. if it starts, than you have vapor lock. you can either reroute the fuel line if possible, away from the source of heat, or insulate the fuel line. I wrapped mine with a thick rubber hose and than use heavy metal foil around it to reflect the heat. it seems to help, but it will still eventually heat up on hot days when stopping for gas.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
dyork
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My tercel:: 1987 tercel wagon. weber carb. roof rack.

Re: 1987 weber carb install runs rough/dies after hot start

Post by dyork »

I will def try that also! that is a def possibility for sure! I did notice it seemed to be worse in the summer.
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