Erich Stein

Is there anything inside the throttle body that needs coolant flowing through it? Can I just run a line straight past that instead ?

amamike91

It is part of the Throttle position sensor. There is not much of a description other than a diagram. There is a temperature controlled( water) valve inside the throttle body which is attached to the TPS. The valve moves to allow air flow to bypass the butterfly in the TBody. When cold it is open and closes when hot.
So if you bypass the water hoses it probably won't run very good. For every action there is an opposite reaction.

Erich Stein

I thought it was just a pipe to tether across there so a rubber hose was not draped across the engine. My throttle body off the truck so I can play with the TPS sensor and calibrate this wonderful contraption. Feels like to me the TPS is attached to the same shaft as the butterfly valve, but I guess I could be wrong. I recently had head gasket failure, so I have no idea what the condition of the valve is inside the throttle body. I can pour water through it, feels like no restriction.

millball

Helps to prevent throttle body icing, which can occur at ambient temps much higher than 32' at higher vacuums and higher humidities

Co_94_PU

iTrader: (-1)

We're not talking about a cold idle valve then?

I'd have to dig out some diagrams, but...

There are Toyota patents related to pre warming air before it enters the combustion chamber, it was a big basis of the fuel economy they were producing over the American makers back in the day.

millball

American cars had hot water heated plates under their carburators back into the early '60s. fords come to mind in particular.

amamike91

This is the diagram I was referring to. The TPS is connected to the butterfly valve. The way I see it is when cold the thermo wax valve is open to allow air to bypass the butterfly valve. When hot would be closed. Water should flow freely at all times. I have yet to find Toyota's description of how it works. This is how I see it. Opinions welcome.

Erich Stein

Wow, I can't find that fancy diagram anywhere. I have some online FSM I printed about the throttle body, but it has no pictures like that. Considering I had head-gasket replace, the wax could be vaporized out of mine - who knows.

millball

Toyota certainly uses coolant temp to control cold idle speed, but this is not the only reason for passing hot water thru the throttle body, as I have already noted.

22RE engines, at least early ones, pass coolant thru a cold idle valve that is completely separate from the throttle body, and pass hot coolant thru their throttle body as well.

Discombobulated

I guess my question is why do you need to bypass it? Just wondering

amamike91

When I bought my truck new back in 90 I picked up all the repair manuals for it. I think some of the later models have different TB's as I have seen in the online 93 FSMs.

millball

I think that there are at least two different 3VZ throttle body types. I know for sure that there are two different 22RE throttle body types.

Erich Stein

My engine does not run right, I am trying to calibrate the throttle body, and I must have it on and off at least 12 times in 3 days. If it was there for no technical reason, I would not need all these hoses, bends, clamps and instead just have 1 clean nice rubber tube going to it's destination.

millball

SIGH...….. I think that you're determined to 'improve' your truck until it won't run at all.

Every last thing on these fuel injected computer controlled trucks is there for some 'technical reason'.

old87yota

Yep, this ^^.

Toyota wouldn't have spent the time, and especially money on designing coolant passages through the throttle body if it was not needed.

What problems are you having?

Erich Stein

I am not afraid of wiring or computers.

millball

The TPS adjustments are actually really simple. The TPS must be set so that it signals 'throttle closed' when the throttle plate is closed, and it must stop sending this signal when the throttle plate is opened ever so slightly.

Simple as that. All the other measurements are to determine if the TPS itself is still functioning correctly, and no adjustments can affect these output measurements.

Erich Stein

As long as this is on the bench, I can work on it. Do this with it on the engine too much work for me. Once I buckle this down and hopefully get engine run again, I do not expect to play fun games removing stuff to see what happens. I only want to make the truck easier for me to work on.

ev13wt

It does run past some sensors though.

scope103

And that is why you belong to YotaTech. http://www.cygnusx1.net/Media/Supra/...taTech/h21.pdf (wax type air valve)

If you bypass the coolant flow through the throttle body, it would be hard to start and keep running. Among other things.