Tested four TVSV's, 3 have problems, got one?

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xirdneh
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Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Tested four TVSV's, 3 have problems, got one?

Post by xirdneh »

I tested four TVSV's and three have problems
i need three working TVSV's, anyone willing to part with one
where is the best deal on new ones?

the FSM test is on page 110
there are three temperature stages
all three bad ones work fine in the first and second stage
all three have problems at the third stage

one will not move past stage two
two do not shut off "N" (lower left picture of stage three)(lower right picture of stage three works as shown)

sure with i could figure out how to rig this up without the TVSV
its like a worded math problem
never could do those
Love those Tercell 4x4 wagons but they sure suffer from road noise.
takza
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Joined: Fri Apr 02, 2004 4:28 am
Location: Tibetan plateau

Re: Tested four TVSV's, 3 have problems, got one?

Post by takza »

Not sure who wrote this:

"It is easy to by-pass the TVSV valve. This valve is supposed to cut out the vac advance when the engine is cold, and cut it back in when it is hot (presumably to reduce emissions, but it also reduce the economy and exhaust valve life). You will get better gas milage when there is alway vacuum to the vac advance. So determine which line goes to the ADVANCE side of the vac advance, and connect it directly to the vac source. The others should be capped off. When it comes time for the emissions inspection, put it all back.

If anything the by-pass will tell you if it is the TVSV valve that is leaking. I would not buy a new one if they are that pricey but get one at a wrecking yard, or try sealing it with RTV (they usually leak around the base where the plastic meets the metal base). I have done both with good results. I refuse to spend money on something that reduces the fuel economy since it is already costly me to have it on the car."

more....

TYPRUS T4WD SETUP:

..........

So, none of my vacuum ports do a lick of anything on silver! HAH!

On white, the bottom port works, but the top pancake is dead.

Where do I have them plumbed?

Bottom port goes up to the part that splits between one of the EGR things and the middle port on the carb (of the three on the passenger side)

Far drivers-side of the top pancake- manifold direct

Pass side top pancake fitting- Normally up to the HAVC, but I put it to the ported vacuum feed on the drivers side top of the carb.

So yeah. I find it funny that the dead-advance car ran infinitly better, got fantastic fuel economy, and moved like a scalded dog.... A scalded dog with what felt like much better than 62 horses!

.......

I have all of my vacuum hoo-hah detached from the VSV and the TVSV, distributor aside.

Whatever sources into the side of the carb is still there.

Hoses are plugged and fitting capped where needed.

Dist bypasses the HACV (high alt compensation?) and utilizes the ported vacuum source above the 2ndary in the side of the air horn above the butterfly valves.


I regularly clean my system out with SeaFoam and/or distilled water. I check my sparkers regularly and do my valve lash about every 10000 miles, as per recommendations from my instructor.

Remember, my instructor is a multiple-ASE Master certified tech who worked on Terc 4wd's from their inception to their end.

....

I'm posting this collected info so you can go ahead and bypass the TVSV and give a detailed account of how to do it.

I'm still using the old repaired TVSV and never got around to testing it...my car runs OK...but I don't currently use vac advance. Tried bypassing everything one time...but car wouldn't run right....some part of the carb or system needs vac.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.

Orwell said: War is peace! Freedom is slavery. Ignorance is strength...

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xirdneh
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Posts: 2124
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Tested four TVSV's, 3 have problems, got one?

Post by xirdneh »

Here is my problem with disconnecting the TVSV
it controls the choke hold opener
its the diaphram thing thats on the front drivers side of the carb (the smaller one of two)
when the car gets warm the vacuum to this thing moves the linkage and pins the choke open(top front of carb)
otherwise the choke blade flops around and sometimes hangs up the fast idle thing on the aft passenger side of carb
causing an unwanted high idle
so i need that thing to work
Love those Tercell 4x4 wagons but they sure suffer from road noise.
takza
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Posts: 4414
Joined: Fri Apr 02, 2004 4:28 am
Location: Tibetan plateau

Re: Tested four TVSV's, 3 have problems, got one?

Post by takza »

The choke opener could have vac all the time and still do it's job?
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.

Orwell said: War is peace! Freedom is slavery. Ignorance is strength...

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: Tested four TVSV's, 3 have problems, got one?

Post by Petros »

I think that is correct, the choke opens by an electric heater, the vac just powers the actuator. I see no reason not to open the choke via the TVSV valve in normal driving. So likely any vac source could be used to actuate the choke.
'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)
xirdneh
Highest Ranking Member
Posts: 2124
Joined: Thu Aug 04, 2005 11:38 am
My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Tested four TVSV's, 3 have problems, got one?

Post by xirdneh »

Actually the choke spring only holds the choke closed.
it is not directly attached to the choke movements it justs rests against it.
the spring keeps on going and eventually when hot is not even touching the choke movements.
so the choke blade just flops around free.
the step down idler on the aft side of carb has almost enough weight to hold it open.
i suppose one could add a split shot to the passenger side of the idler to give some weight.
the choke hold opener on the front drivers side is supposed to hold it open under vacuum.

i took a dremel motor with a 1/32 thick cutting wheel
and carefully cut the brass crimps free on the TVSV
dissasembled the thing
then i heated the base in hot water and measured how far the piston pin came out
it varied on all four i tested .462 to .6 inches
the .6 one was the only one that moves far enough to function properly (that one i broke removing engine, it was good)
so i plan to shim the piston pin .062-.125 inches on the bad ones
then assemble and hold it together in a vise (temporary sealed with gasket comp)
then heat the end and test it
if it works i will wire the thing together like the guy on this forum did on previous topic
Love those Tercell 4x4 wagons but they sure suffer from road noise.
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