I bought and rebuilt my first RX-7 last summer, and now that it has warmed up a bit outside I was able to finally try and start it up again. I had left off last with the engine finally able to idle on its own, but the cooling system didnt seem to be working correctly. So I just replaced the thermostat and topped off the coolant in hopes that it would remedy the problem.

Alas when I started up the car it had quite a bit of trouble idleing and whiteish smoke started to come out of the exhaust. I am quite afraid that I may have a leak going on, but would like some second opinion...what does everyone seem to think is going on here?

http://www.youtube.com/watch?v=KCeoshD6m_c

 

This happened to me once, on my N/A. The Pretty much the exact problem. I thought it was a stuck seal which would happen now and then but it wasn't. I then pulled the CAS out and noticed it was one tooth off. Some how it was able to start up and run but run just like yours and smoked out the back.

 

do you have somekind of aftermarket fuel controller? maybe running way too rich. what does the smoke smell like?

my car has a leaking injector and i get fumes similar to what your smoke looks like smells like fuel though.

 

how long have you ran it so far? did you used lubricants while rebuilding the engine? it could just be them burning off.. I filled my engine with diesel a few days ago to unstick a seal and it smoked for 20 minutes, if you have oil in the combustion chamber they could be burning off and some of the stuff could have been shot into the exhaust system and slowly burning off. I once installed an exhaust system on another car I owned that came off a car with a blown engine and there was oil coated inside the pipes and it took over an hour of idling and driving before the smoke cleared up, i thought something was blown for a bit.

 

Yeah, there was a good bit of vasaline in the engine from the assembly, but ive had it run a number of times (10+) but never for more than 15 mintues because of the above stated cooling issue so I couldnt leave it running without it threatening to overheat. ill have to start it up a couple more times and see if it slowly disappears, I'm just afraid I'm doing more damage by running it and not figuring out what is wrong.

The car doesnt have any aftermarket fuel controller, all running off of the stock ecu, i removed all of the emissions and it has the blockoff plates installed. The injectors should be all set, I had them fully cleaned by Injector-Rehab (great business highly recommended), and they were in great shape when they came back.

Ill take a look at adjusting the CAS and see if that does anything for me.

 

Any updates?

 

well, by the time you got to the back of the car there didn't seem to be too much white smoke, but there was a nice cloud behind it. I'd get it good and hot, pull the plugs in the morning and make sure they aint wet.

 

If it doesn't smell like coolant it's probably not coolant. I wish you had a wideband on the car so you could check the mixture. Sometimes these cars will smoke a little bit on startup but once they reach full operating temp they are fine.

 

Sadly no updates on it, I had to get back to school and wont be back home to work on the car till mid may.
Trust me I wish I could afford a wideband to put on there, its high on the list of stuff to get as soon as I can.

I am going to look into readjusting the TPS as soon as I get home, I think may really be the issue. I'm also going to try and adjust the variable resistor and maybe try and run it a bit leaner. Ill look into how the exhaust smells next time I start it up too.

 

As far as the overheating is concerned: this may sound dumb, but you've got to check everything.....

did you let the thermostat open up before you topped off the coolant? it might not have enough fluids in there. just a guess.

 

- smell that white cloud

- what are you using for a radiator fan?

- start the car with the rad cap removed. Now get out and look into it, at the fluid inside. What is happening?

Elaborate on this, please.

 

Just the stock fan running off of the water pump pully


I let the engine warm up and kept my eye on the water temp. Now I am pretty sure that the needle should stop and hover just under halfway up on the dial. But the needle kept moving up past 1/2 and was approaching 3/4 of the sweep with no signs of stopping. I shut it off then and havent ran it long enough to have it warm up that much since. The last time I ran it was that video i took in the original post. I havent had a chance or tried to warm it up since.

 

One more thing for you to do, then. Warm up the car and when the temp gets up to half and then past that, get out and see what that fan is doing. Is it blowing hard or just spinning? You won't be able to tell by just listening - stand back by the wiper motor or trailing coil and feel it. The clutch on the stock fan on my 90 puked last summer. I found out when it overheated in city traffic and when I pulled over and got out, everything seemed normal except for the fan's output - it was hardly moving any air.



For an s4 na, 1/3 to 1/4 is normal. I've nil experience with the tII, but 3/4 certainly sounds like bad news.

 

my s4 n/a gets up to around 1/2 or a little more when you drive hard in warmer weather for a good distance. Im going to add some water wetter or something similar.


Also are you running antifreeze/coolant or distilled water? The water will show higher temps than the antifreeze/coolant.


Other than that have you checked the new Thermostat by boiling it on the stove to see if it opens up? Also is it an oem mazda part or something from some other auto parts place? I had 4 thermostats test BAD brand new out of the package for a firebird i used to have. Causing major problems


Also i have seen pics on here where some people pull rebuilds apart just to find odd things and missing parts in the coolant passages

 

Will do.

yeah but my car is idling in weather that wasnt warmer than 50 degrees out.


Yes, 50/50 antifreeze water mix


It is Mazda OEM, bought it directly from a dealership. It used to have a knockoff brand in it, came in it from the previous owner. Ill have to look into that boiling water thing...


This is a step I would love to avoid!

 

to test the thermostat just pull it out and stick it in a pot of boiling water and if it comes open then it is good if it doesnt then its junk. Leave it in for at least 30 seconds

 

Timing sounds way off