Thermowax Removal from TB
 

final question for the night (I promise!)

So I don't run coolant through the Throttle Body (it's looped from the rear back to the front housing) and have the AWS on the UIM blocked off.

Is it ok to remove the thermowax unit from the throttle body? :dunno:

On the FD is it not as simple as removing the hose coming from the block to the TB and plugging the holes?

The thermowax uses the hot coolant to rotate the fast idle cam down and close the throttle plate to its normal resting position. If you remove the coolant hose but don't remove the thermowax, the fast idle cam will not come down completely. Thus the throttle plate will remain open slightly. You can see this if you monitor the TPS voltages--with the fast idle cam up ("cold") position, the narrow range voltage will usually be 1.10-1.20 volts. When the fast idle cam is rotated down, narrow range voltage will be maybe .80-1.00 volts. With the cam rotated down (like on a stock TB), the throttle plate opening angle is adjusted by the stop screw (throttle adjust screw).

how can the thermowax be completely removed with out any issues?

Simply bypassing the TB is best. However, you do have to tie-off the cam or it will interfere.

I'm with the OP though... has anyone removed all those components altogether? Seems sensible enough.

Yes, many people have removed all those components.

This might explain why I could never get both numbers on my TPS within range. Thermowax is gone!

Thanks all!

Did you use any block-off plates or plug the holes is any manner? Or can you just simply remove the unit?

For the termowax I just took it off - I could weld it up but I'm not entirely sure it's needed as coolant *appears* to only flow through the holes - meaning I don't think it's a vacuum issue.

For the AWS on the UIM, I used block-off plates.



EDIT: I should state this is on a throttle body that is not yet on the car. I'm in the process of working on this one and cleaning and prepping the piece for either plating or painting (haven't decided yet). Linkage will be plated but debating the body itself. The UIM is already blocked off and this IS ON the car. The TB on the car has the coolant line bypassed but has all the units on the TB... (Thermowax, etc..) and does not have a safety wire holding the 2ndary choke mechanism open - I think I know now why it always idled funky.

You can rotate the fast idle cam with your finger and see the throttle linkage thing rotate. That's what happens when the hot coolant moves the thermowax.


http://www.rotaryresurrection.com/3r...ov_nonseq.html , scroll down to step 19

thermowax removed:

http://www.rotaryresurrection.com/3r...q/image043.jpg

That is what it looked like to me too but I just wanted to make sure before I just yanked it off there. I have all the other block-off plates installed. It always did irritate me that my TPS was always in spec on all but one closed setting.. Now I guess I know why. I never worried about it b/c everything always run perfectly. After I get that off there it should fall into spec no worries! Thanks for asking this question.

about a month ago or so, I completely removed the TB, disassembled and reassembled it. during the reassemble, I removed the fast idle cam, thermowax unit, and basically everything except the throttle linkage, seems to be working perfectly. and I will admit, it looks a lot simpler.

Did you replace the o-ring between the TB and intake elbow when you reinstalled? I can't seem to find a replacement, so I have been just reusing mine.

http://www.mazdatrix.com/c-2.htm

http://www.mazdatrix.com/getprice.as...m=13-W690-N390

Thanks

I used the silicon sensor safe gasket material, and haven't had a vacuum leak so far.

I got my last TB gasket from Ray at Malloy. Surely he would have a few as well.

resurrecting this thread. Is there a How-To on how to remove the Thermowax system? I'm going to be upgrading from PFC to Haltech and I want to remove this and the dashpot to simplify my setup. Need to know what's involved and ultimately if I should do this or keep it.

Just unbolt the thermowax and coolant pipe section from the TB, wind in the idle bleed screw then out half a turn and re set up the TB, there are guides for this on here.

For the coolant, easiest option is to run a hose from the nipple on the rear iron to the WP housing directly to bypass the TB. If you're feeling keen and don't want a coolant pipe running under the UIM then you can remove the nipples and tap them for an 1/8 NPT plug. The rear iron one can be fun to remove with the engine in the car, so I'd be carful with this option.

After having FD's with and without personally I'd keep it, the system works well.

Yeah it's not hard, just run the hose that normally goes from the rear iron to the TB from the rear iron to the WP housing. Trying to cap those nipples ends up in failure more often than not.

The thermowax is held to the TB with screws, make sure to use a Vessel-type screwdriver or an impact driver to remove them. They are TIGHT and can strip easily.

Dale