Hi all, I am wondering if anybody has parts left over from doing the TB mod? I am looking for the choke valve vacuum actuator, That's what i call it since it makes sense. I have attached a pic of the part i am talking about. I have posted in the classifieds but have not gotten anything yet.

Thanks

 

Just curious why you are worried about replacing that?

The reason i ask is because the car will be perfectly fine that system not functioning. If you havent removed the choke butterflies, you need to keep it there so the spring will hold them open but otherwise, it doesn't need to be functional. I still have the butterflies there and the valve just to hold them open, but I have disabled the entire system because the diaphram is busted in the actuator.

 

Isn't that needed for cold start idle, not the subzero but just not a warm engine? That is what i thought that was for.

 

no, it keeps the secondaries from working until the engine is warm. It's to keep idiots from gunning the car when its ice cold.

If you aren't an idiot, you don't need it.

 

Oh I thought it was essentially a vacuum actuated choke.

 

Fuel injected cars don't have chokes

Least none that i've ever seen

 

i probably have one somewhere but you'd have to really want it for me to bother looking for it. (because i know it will be in the last place i look)

 

I know EFI vehicles don't have a choke but it is essentially what the computer does by itself when cold. If i remember chokes correctly they limits the air, and since that was the only thing i thought it would be. Well i guess it is back to playing with the TB and TPS to get her to idle correctly.

 

The computer doesn't need a choke. Carbs do because you need more fuel to start a cold engine, which is what that choke did on carbs, restricted air so there was more fuel

EFI vehicles do this automatically by making the injectors spray more fuel going off of coolant and air temperature

 

I made a little short video for you. Currently uploading it to the youtubes.

 

And here it is. Watch the video OP.

 

Thanks jjwalker for the video, you explained it well.
lduley, it does the same effect as a choke, lower AFR until it warms up. which is kind of what i said.

Thanks for the info guys

 

it doesn't affect the richness when cold, or at least it isn't supposed to unless the secondaries aren't adjusted properly.

plenty of people wind up messing with the secondary set screw though, since it is easy to access on the n/a cars and it affects idle speed however it also affects idle quality too.

 

It just keeps the secondaries from working at cold temperature, that's it. It is a dummy feature kind of like the oil metering pump. Combustion chamber lubrication is critical in a wankel rotary engine so mazda added the OMP so that people didn't need to premix their gasoline like a leaf blower which needs the same thing. Premixing the gas is FAR superior than the oil metering system but you can't apply a warranty to an engine and expect to make any profit if you don't cater to the morons and lazy folk out there who be damned can't properly mix oil in their gas.

The same applies to 2 stroke boat motors. I work on boats all the time and guess what, they all have a 2 stroke metering system now. When I was a kid you had to mix it in the gas tanks properly but nowadays, there is a system to do it for you to keep the lazy ignorant people happy.

To end my little rant (lol) That little valve and system is just a stopgap measure for the critically ignorant people who roam this earth.

 

So I set the TPS via the Ohm method and i am idling at about 1750-2000 when warm. and a hesitation/buck at 2500ish rpm. any ideas

 

You can't set the TPS unless it is idling at the proper rpm range. W/the engine idling, press upwards on the front throttle linkage and see if the idle drops or not.

 

I have somewhat the same problem. My FC is a 90 S5 NA, and everything is stock. Only thing that's NOT hooked up is the hose that goes from the rear iron plate to the Thermowax.

My FC, when cold surges between 1500-2000. When warmed up after I drive it goes between 1200-1500. The engine is rebuilt, currently at 1200+ miles on it. I've done EXACTLY what you mentioned above, and my idle DOES drop, but it won't stay there, even after warmed up. Unless I go to a hotter area away from the San Francisco Bay Area. What does else should I try?

I've already checked for leaks with everything mentioned on the forum and even set my CAS and TPS according to the FSM, but to no avail. I plan to do a compression check later.

 

You need to check to see if your fast idle cam is set correctly. The thermowax causes the rear throttle linkage to close slowly as the engine coolant heats up thus dropping the idle speed. Are you suggesting the coolant hose is not hooked up (and that would prevent your idle from dropping to the correct levels) or is the hose a vacuum hose connected to the thermovalve?

 

The coolant hose isn't attached to the thermowax. The hose that goes to the diaphragm which jjwalker pointed out is connected (I replaced the hose). I don't remember if there WAS a coolant hose connected to the thermowax when I pulled the motor out over 2 years ago. I'll check out the Fast Idle Cam set screw, as I haven't touched that at all.

I do remember the Previous Owner had a zip tie holding a a throttle part, either by the throttle cable or or the TPS/diaphragm. But when I took it off, it didn't mess with the idle. This was all before I pulled the motor to have it rebuilt.

 

If the thermowax/fast idle cam is not set properly then the car would idle at a high rpm regardless of the engine being warmed up (the idle could drop a bit as the engine is warmed because the heat created by a warmed engine would affect the thermowax to a certain extent w/o the help of the coolant but it won't work as effective as needed). If this aspect of the car is not working properly then something else would have to be done to prevent the throttle plates from being open too much thus causing the high idle such as something forcing the plates closed like the zip tie.

 

Thanks a lot satch. That was something I had read about doing, but didn't try due to lack of photos for visual aide to locate it. It would appear my thermowax plunger is stuck, despite having driven the car around to get it to operating temperature. Now I know where to go to next in troubleshooting. I did adjust the Cam Adjust Screw as it was out of spec, and that did away with the surging idle. Definitely replacing thermowax and hooking it back up to stock.

 

Remember, the thermowax needs a source of coolant to work off of or it will basically cause the rod extending from the rear of the unit to become stationary. Just run the proper hose to it and see if it improves things.