TVSV and Cooling Fan - '86 SR5

Post by **ARCHINSTL** » Sat May 07, 2005 11:32 pm

TVSV and Cooling Fan - '86 SR5
Well, I think I fixed the starting difficulties, at least for May weather. I installed a new Bosch 12051 oxygen sensor and cleaned the several carb pivots I missed the other day. The old sensor was pretty burnt-looking and, I presume, 170K miles old. I also replaced a possibly leaking 3" vac tube leading to a dome-shaped thing on the carb's left side front. The idle fluctuates between 800 to 1100 rpm, but settles at around 900 or so - OK?
The rest of the little vac tubes look OK, but since I bought 12' of tubing, I might as well replace them.
takza mentioned about the TVSV being easily broken. If the TVSV is a little black plastic tower with 4 vac lines, inserted into the upper radiator hose, then I think it IS broken. At least it can be pulled from its base and then a thin metal tube and a little hat-shaped removable cap are visible. This is certainly a fragile piece in a rather vulnerable location. When I replace it I shall have to rig some kind of cage for protection,
What are the results of this device being broken? My problems, or something else? The Autozone/other repair sites do not list any consequences, nor did I find a mention on the ToyotaNation site either. I presume this is a dealer-only part; at least I could not find it with a cursory Google Toyota parts search.
HOWEVER - there is still massive hesitation between 1000 and 2000 rpm. What I've done so far has not fixed this. There is no power between those two points, and the enginve still has to be revved to 3K and the clutch slipped to lurch along, and then the going is anything but smooth. Should I try superglueing the TVSV until I can get one from Toyota? Fortunately I don't have to torture the clutch in daily driving, as I have another car.
My carb education was on '46 Fords and English SU's, so this "modern" fuel system is pretty much a mystery to me - sorry.
Is my test of the radiator fan correct? With the ignition on and the connector pulled open, shouldn't the fan run? I'm particualrly sensitive to this, as the fan/switch failed on my '83 and my Sidter did not notice the overheating engine and cracked the head to the tune of 1100 1985 dollars.
Thank you all for your attention.
Tom M.

Typrus · Post by **Typrus** » Sat May 07, 2005 11:43 pm

Pull the wire to the sensor at the bottom of the radiator, with fan connected to its power cable, then turn ignition to the ON position. The fan should come on.
DO NOT try plugging in or unplugging ANYTHING with the key in the ignition.

dug320 · Post by **dug320** » Sun May 08, 2005 1:30 am

TVSV is a dealer only part. Two years ago the NAPA and others used to carry them. I have yet to see anything stick to the black "plastic" on the TVSV. I tried everything (crazy glue, epoxy, silicone, GOOP, ether based solvents) with no lasting results.

If it cracked it needs to be replaced.

takza · Post by **takza** » Sun May 08, 2005 5:07 am

The TVSV is fixable...check the pic on the bottom of the first post. I have another one, but am still using the one I repaired.

Don't get dirt inside it...don't lose the lube in there.

Just need some soft iron wire and putty type epoxy. And patience.

<a href='http://tercel4wd.com/invision/index.php ... &f=7&t=204' target='_blank'>http://tercel4wd.com/invision/index.php ... 7&t=204</a>

Post by **ARCHINSTL** » Sun May 08, 2005 3:42 pm

Typrus - thanks for the tip on the fan. I will try that tonight.

takza - thanks for the tip on the TVSV. Externally ours look identical. However, the insides of mine do not look like the one in your (excellent) photos. Mine has a much longer thin metal tube about 2mm thick and has a removable little metal hat-shaped piece on top. No spring and no black tubular piece surrounding the end of the spring, and also no sign of the lube you mentioned. Does this seem to be a different type or did someone lose something before? If parts are lost I guess it would be fruitless to attempt a repair? What effect does this have on the operation of the engine - possibly the hesitation I mentioned ?

I note that the white '86 on eBay in VA is now up to $2550, with 4 hours to go. Is this a new record for modern times?

Thanks, all.
Tom M.

takza · Post by **takza** » Mon May 09, 2005 5:51 am

Well it needs to seal...since it acts as an vac switch with the black valve moving up-down depending on engine temps. Sounds like some parts are missing....though they could have changed the design....

shogun · Post by **shogun** » Mon May 09, 2005 11:38 am

is there a good replacemet or upgrade for the cooling fan?