AAP pump connected to engine vacuum directly

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Dumindu
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My tercel:: 1987 Toyota tercle 4wd DX Wagon 1452CC
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AAP pump connected to engine vacuum directly

Post by Dumindu » Mon Aug 05, 2019 8:12 pm

My car is a 1987 Toyota Tercel DX Wagon RHD 1452cc manual driven car. It has a Aisen 2 barrel carburetor.

AAP pump of my car connected to the engine vacuum directly. It should be connected to the vacuum via a TVSV thermostatic valve. My car TVSV valve broken and it is difficult to find TVSV valves now.

Could that connection cause a serious problem?

xirdneh
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Re: AAP pump connected to engine vacuum directly

Post by xirdneh » Mon Aug 05, 2019 8:37 pm

just cap the AAP
you can live without it
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Mark
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Re: AAP pump connected to engine vacuum directly

Post by Mark » Mon Aug 05, 2019 8:53 pm

xirdneh wrote:
Mon Aug 05, 2019 8:37 pm
just cap the AAP
you can live without it
I agree. Mine are both disconnected and I only notice in winter when I try to accelerate quickly from idle for about the first 5 minutes of driving until the engine warms up a bit. I doubt it ever gets cold enough in Sri Lanka for the AAP to have a purpose.

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Petros
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Re: AAP pump connected to engine vacuum directly

Post by Petros » Mon Aug 05, 2019 11:29 pm

it should not be connected directly to vacuum. it should only be activated during acceleration when it is running after a cold start. the TVSV isolates it after warm up.

if the AAP is leaky, it will be the cause of your flooding and poor fuel economy.

Important: cap off both ends of vac line, it will run fine without it.

On really cold morning starts, it just means you will have to carefully warm it up, and do slow accelerations until warm. At worst you will risk a slight flat spot on hard acceleration when cold. once warm you do not need it, and it should be isolated from the system anyway. by capping it off, it will just act like it should after warm up.
'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)

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Dumindu
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My tercel:: 1987 Toyota tercle 4wd DX Wagon 1452CC
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Re: AAP pump connected to engine vacuum directly

Post by Dumindu » Tue Aug 06, 2019 1:13 am

Thank you all for your valuable advice.

My area in Sri Lanka is so hot even at the night (22-28 Centigrade) and would not need AAP pump.

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Dumindu
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My tercel:: 1987 Toyota tercle 4wd DX Wagon 1452CC
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Re: AAP pump connected to engine vacuum directly

Post by Dumindu » Wed Aug 07, 2019 5:47 am

Thank you again Mr. Petros.

As you told it was the major contribution for the fuel wastage of my car.

After AAP pump capped, 80% of the problem solved.

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