TweakGames

iTrader: (3)

Hello all. I am getting sick and tired of my car taking SOOOO long to get warm and letting the RPM drop to a decent level (750 rpm). The only way it will completely heat up the thermal wax is if I drive the car for 20 mins semi hard, and THEN let it sit for another 10 mins.(with the car off) My guess is it just sits and bakes the TW? But then it will hold 750 all day long. My car is warm, my water temp is 1/4 up like it should be, but I have to let the car sit before the idle will hold at 750. It is normally around 1400ish (pre sit), but will somewhat creep down to about 1100 or 1000 if I am lucky. I am about to just remove the TW, but maybe there is something else I can do?

If I manually force the throttle plates closed a little it holds idle perfectly!

Any ideas?

Thanks
~Tweak

MmSadda

iTrader: (2)

Well, it seems the question in the title, and the question in your post are slightly different.

But to answer your first question, yes. The thermal wax absolutely can go bad. When my engine was rebuilt, it's the one thing my builder said he doesn't cover in the warranty.

The Wankler

iTrader: (14)

Check the feed line. On the back of the housing follow the line to TB. It may be clogged somewhere in that line. Otherwise, pull the TB off and pull the TWP off and see if it is clogged.

TweakGames

iTrader: (3)

Opps, yes I kinda did stray away, but I was wondering if they can go bad, and if how how would I check. I was thinking of just getting rid of it also midway through the post.

Ok, thanks guys, I will most definitely check the lines. Wankler, do you mean the coolant lines?

MmSadda

iTrader: (2)

It's cool. I'd give you more information if I could, but my knowledge surrounding the thermal wax is rather lacking. Hell, I thought it was called "Thermawax" or "Therma-wax" until you posted. haha

TweakGames

iTrader: (3)

haha well, I could most definitely be wrong also, I was getting little to no search results, so maybe it is spelled that way. O.o

Yeah, I can't wait to get my haltech installed so I can ditch the TW!

MmSadda

iTrader: (2)

I'd edit my past post if I could, but it's been too long, apparently.

We were both wrong, actually. It's spelled "Thermowax", at least in several threads that I found.

TweakGames

iTrader: (3)

Yeah that sounds better, thermowax . Anyways this is what I have found out. I went and drove my car for 20 mins, city and highway, and then went under the hood to set the TPS. 3kOhm... O.o and even if I manually close the throttle it only goes down to like 2.5kohm. I pinched the coolant hose coming off the back of the engine, no fluid. I pinched the coolant hoses going from the water pump to the BAC, no fluid, I pinches the coolant hose coming off the back to the rear of the throttle body, no fluid (or at least I don't think there is any in there, I can EASILY pinch it shut and I was doing it while the car was on).

BTW, this is an s4 NA. There is NO way I would be able to get that TPS into spec with the thermowax holding the throttle open that much, you can only adjust it like .5kohm.

Any ideas? I was thinking that maybe my thermostat is acting weird, maybe not opening or stick open?

Thanks
~Tweak

TehMonkay

iTrader: (-1)

Throttle body may be dirty, that might be it you know. Personally, i'd just take it off and throw it in a parts washers, sans TPS at least, and see what happens after adjusting it to spec from the FSM.

TweakGames

iTrader: (3)

I'm pretty sure that those coolant lines should be pressurized and hot from the coolant though?

TehMonkay

iTrader: (-1)

Oh, yeah, clean those out too, lol. Make sure the path through the BAC is clean too if youre still using that as well.

TweakGames

iTrader: (3)

Wow I REALLY don't feel like doing that right now haha. I am at a place with no/limited tools and schucks is closed. Schucks just LOVES it when I use their tools. I will have to do it tomorrow.

But from what I am thinking right now, since those lines arn't getting water, somewhere between the water pump and the return back to the engine... (or does it go the other way, from the back of the engine, through the TW, through the bac, and return to the back of the water pump?) there is something blocking everything...

The only reason the idle drops down after letting it sit after driving it hard is because the engines heat from sitting physically warms up the TW, instead of the coolant. Do I sound completly far off or does that sound reasonable?

NJGreenBudd

iTrader: (1)

I have heard of them going bad due to the "wax" leaking out over time.

It sounds like the thermowax is eventually letting it close it's just taking a while, can you see how much the piston is moving on it?

alexdimen

iTrader: (13)

Is the car actually getting up to temperature in a timely manner? Try an IR thermometer if you can borrow one.

TweakGames

iTrader: (3)

That is another thing, it takes QUITE a while for the car to get warm. I have never had a car that is so hard to get warm and stay warm... Maybe my thermostat is stuck open??

TweakGames

iTrader: (3)

Hello all again. Sorry to take so long to get back. I am currently waiting on a new (used) thermal wax to get sent to my from my house. (Currently I am at college 3 hours away) I am almost 100% sure it is the TW from doing some research on the forum and doing some tests.

Here is a link to another very useful thread.
https://www.rx7club.com/showthread.p...owax+high+idle

I am going to be replacing both my thermistat and my TW unit. I should have results by the end of the week.

As for some people that have PMed me, they have the same issues as me, but only when it is cold. I think it is STILL the TW being dead/not doing its job, but when it is warm (outside) the little extra heat from the outside AND the engine bays temp cause the piston to go up. When it is cold, that is when the piston goes down and opens up the throttle plates a little, raising the idle as though you had your foot on the gas just a litttttttle bit.

I hope this helps, and I will have results soon.

TweakGames

iTrader: (3)

ok, so update as promised.

YES, thermowax can go bad. I took mine off and inspected it to find wax actually leaking out past the little plastic thing that screws in. Some was old and dry, some was somewhat newer. Since the wax leaked out, even if the thermowax unit got warm, it only had 1/2 the wax to heat up and expand. I replaced it and my idle dropped down to 1000 steady and smooth.
I think I have a minor vac leak somewhere keeping me from going 750, although sometimes now it will drop down there.

Now I have a weird problem hehe. I am trying to get my timing in check because my idle is under 1000, but when ever I line up the little pin to the first mark on my pully my idle raises. (so when I advance the timing my idle rmp goes up) and will go over 1000 causing bouncing RPM. So I set it between the first and second mark on the pully and it seems to be just fine. I get good gas milage so it must be ok I would think.

Anyways, if you suspenct maybe your thermowax visually inspect it and see if wax leaked out right around where the plastic valve screws in.

Good luck all. My car is sooo much easier to drive now, no backfires and bucking on decel.

rmjmotor

I drive my FC just about every day, with a Haltech e6X, start it in the morning, hold the pedal at 1500 rpms (only if its cold) for about 30 seconds, and no worries, car idles great at around 850