Slandd

Hey, I'm still currently looking throughout the forums since I think I have more than one problem currently. But if anyone has a suggestion I would greatly appreciate it. I have yet to do anything on the vehicle, however, I am currently going to knock out STU and Sterlings guides in a bit that's loosely around the problem. When I start the car there is blue smoke coming from this thing....



I'm not even sure what it's called lol. I can see that it is part of the exhaust pipe but after that i'm all ???'s. I've read that these rotaries burn oil and since I only know about pistons I can only presume that i'm burning oil?

Also the car sputters to a stop after 2k rpm, I'm going to try and do Sterlings guide once I find it if I can, but if someone has a better suggestion in the middle/midst of me doing this that too would be greatly appreciated.

I just picked up this vehicle about 2 1/2 weeks ago for my kid brother so he can start taking college courses while he's in highschool. I'ts a 1979 Mazda Rx-7. I have yet to do any tune ups or fluid changes etc....hm typing this sure helps maybe I should try doing a tune up first

Tune up: oil change, tranny flush, radiator flush, (can i flush the rear gear axle or just top it off?). Am I missing anything? Also I'm not going to replace the cap, wires, or plugs yet, waiting to research and receive the 2gcrdifds (forgot how to spell it) system. But if this could also be a cause for the blue smoke and bad idle I may hold off on the independent firing system upgrade.

Thanks all for any help that you can provide.

Twilightoptics

iTrader: (1)

I like how no one is touching this post!

I'll bite....

Is there exhaust coming out of the two shiney muffler tips with the engine running?

murben

lol... did somebody put a muffler on there just for show and try to hide a straight pipe?

Slandd

There is no exhaust coming from the two pipes. Is that what it is, a straight pipe? Would I check for this by following the small single pipe with the blue smoke up to the headers? Btw thanks for helping guys.

Twilightoptics

iTrader: (1)

Follow the header down and see what' it goes into and out of. Definitely looks like someone ditched the muffler. Is it definingly loud?

Slandd

Yup definentely loud, but then again I could never get the car to idle so idk what it's suppose to sound like, since I am also new to this car.

btw if anyone can look into the car and tell me if theirs has a hose on it or a plug of some sort. About to change out my master and slave cylinders for my clutch and I followed the line and noticed this....



Thanks again, about to check that straight pipe idea.

rotordogg

iTrader: (4)

That is the bleeder valve on the clutch slave cylinder. You open that to bleed the hydraulics just like you would bleed your brakes. There used to be a small rubber cap on it, but the cap isn't necessary. Just keeps dirt and debris from collecting in the bleeder.

I think blue smoke all the time is usually oil getting into the intake chambers. If you are pre-mixing the fuel, you may have added to much oil. If you are not pre-mixing, the oil metering pump injects oil into the engine and it may be stuck wide open. Or it could be the oil seals inside the engine starting to go.

That third pipe makes me laugh. Get the exhaust re-routed into the muffler. You will enjoy the ride so much more.

Slandd

Hey thanks for the info rotordogg. Sorry if this is a newb question...oil metering pump is the oil pump right? Or is it something else entirely? What is the fix for a "stuck wide open" omp? I've tried searching and have only come up with "I need to remove OMP" but then other posts strongly oppose this.

As for the third pipe





I have no idea what that's suppose to be or why it's there...however it doesn't look welded on but then again...what do I know XD

-Gamah

iTrader: (1)

I was thinking this, but it seemed so preposterous that I was afraid to post it.

Slandd

^^ so from those pictures do you think it's a straight pipe?

CobraStngSVT

ditto... lol

murben

Sorry... I don't know about anyone else, but I can't tell a thing from those pictures. Best thing to do is climb under the car and follow the exhaust pipe all the way back and see where it goes. Start where the headers come down off of the motor and follow it to the muffler/pipe. It should be pretty obvious as to what is connected and what is not.

One thing I will tell you, don't jack the car up on the unibody like you have in your picture, you will bend the car. The floor jack should only be put under the rear differential or the cross member in the front, depending on where you need the car lifted. And remember to use jack stands!

murben

Oh, and oil metering pump is a small pump on the side of the carb that injects small amounts of oil into the fuel. It helps keep the apex seals lubricated. Don't remove the OMP unless you want to premix by adding oil to your gas every time you fill up. Not sure what could cause it to stick wide open.

Is it just smoking like that on a cold start? have you let it run to see if the smoke eventually goes away once the engine is warm? How many miles are on the car?

DivinDriver

iTrader: (15)

The pipe with the blue smoke coming out of it is the exit for the cooling air flow from your thermal reactor & "air duct" (which is what Mazda calls the front section of exhaust pipe on an SA).

If exhaust gas is coming out it, you most probably have a broken/burned out air duct, a ruptured thermal reactor, or possibly a really badly-failed air-control valve check valve.

If no exhaust gases at all are coming out the muffler, then it's not the air control valve; it's either the thermal reactor or air duct that has failed internally, and possibly a blockage further back in the system that caused it. Part of your inability to idle may be from way too much back pressure due to internal exhaust system failure.

Diagram of SA exhaust:


Pipe in question is the "cooling air pipe," seen in the lower left.

Cooling air flow begins at the air pump, goes through the air control valve, then the outer jacket of the thermal reactor, then the outer layer of the front part of the air duct, then out that pipe in your first picture.

Named parts of the system front part of the system:



Couple other views of the stock exhaust system off the car:





This exhaust system is unique to the SA's. Used parts in serviceable shape are not easy to find. Some new parts are still available, but hideously expensive (last new Air Duct I saw a price on was over $900 from Mazda)

If you don't have to pass smog, you're far better off removing it and going to a decent header/pre-silencer/performance muffler system.

To diagnose this, you need to pull the exhaust system out and check for main-path blockages as well as side-path ruptures. Not as bad as it sounds.

The blue smoke means you're either burning too much oil, or a smurf has been elected Pope.

Slandd

@murben HEY thanks for the info! Will remember the jacking points from now on. And I had two jack stands I just always put a floor jack almost all the way up on the side I'm currently on just in case of the T.T unknown.

@divindriver man thanks so much for the detailed info, I am going to try and take it all apart right now and see what's going on inside. Unfortunately for me I live in california so a smog is required. So aftermarket exhausts cant pass smog because of visual or because of flow? Sorry for the newb question.

DivinDriver

iTrader: (15)

Aftermarket front exhaust on an SA will fail visual; unless you have one custom made with a cat & proper plumbing for it to connect from the air pump, it'll likely fail on numbers too without the thermal reactor.

There's no cat on the 79's/80's; 80 was the last year not to have one. Instead of a manifold and cat, they have the 'thermal reactor' which essentially works like an afterburning oven, using heat & air instead of a catalyst to burn up unburned fuel.

That thing that looks like a cat is actually a heat exchanger, used to pre-heat the injection air that goes into the thermal reactor.

I don't know what level of smog test is required in Sac-to; down here in the basin it's basically got all the charm of a body-cavity search conducted while you run on a treadmill.

Slandd

Oh man what a head ache. I think i'm going to bug my girlfriend to move to Oregon or Texas instead. Thanks for the help LOL jk can't move -__- but a man can dream. If it will fail in numbers then it won't help =/ I know a guy who doesn't do visual but he's strict on numbers. So I looked at RB exhausts...but I'm not sure if it's impossible or does not exist...can I put a cat on it?? lols sorry if it's a silly question.

btw why is yours so clean T.T

Slandd

@murben It dies out when it hits 2k rpm on the idle so I can't make it run for too long to see if the smoke clears after warm up. Also there is 133k miles on the car but the last owner said he did a rebuild at 111kish.

DivinDriver

iTrader: (15)

Short answer: because I've spent years cleaning it up, after spending decades getting it dirty.

Long answer: Read this - https://www.rx7club.com/build-threads-293/project-resurrection-running-log-770184/
& note the start date, heh.

Slandd

^^ lols I have read that before, I think I pm'd you about it too =P

Anyways I have a new development. There is less smoke coming from the third pipe, still whiteish blue though...is that normal? Also I drove the car around for a bit and couldn't get it past 5k rpm? Thanks for any help guys.

btw was wondering if a tune up would be a good idea at this point in time or should I wait to further access the problems (i don't want to waste oil T.T because I only have around $200.00 left to get this thing at least drive-able up the drive way so as to not get a parking violation - currently on non-op).

Slandd

Haven't gotten around to pulling the exhaust down, the slave cylinder just went out and the clutch won't engage. I have noted that there is exhaust fumes coming out of the exhaust. Also I've researched that if the car is burning up too much oil it could possibly be the O-Rings...but what other possibilities should I check before I sink money into a rebuild of some sort?

DivinDriver

iTrader: (15)

Step one is to get it so it can idle, if possible. Without a stable idle, you really can't test anything else well.

Second step would be to check you OMP and make sure it's adjusted right... which is a lot easier if you can get the engine sable

third step is to chase down why you're smoking out that vet tube; it could be something as dumb as oil having pooled in there, slowly burning off

Best way to determine if you're burning too much oil is to measure how many miles you can drive before you need to add a quart of oil. Anything less than 500 miles to a quart usually means it's rebuild time.

Also, if your thermal reactor isnt working right, you're for sure going to be running rich and not burning off any excess... which can also cause smoking.

Does the smoke smell like burning oil? Or does it smell like unburned gas? You could just be running way too rich & have a borked emissions system.

Always solve known issues first, before trying to solve things that may not actually be issues. One step at a time.

Slandd

DAMN DD thanks for the info, I'm going to read that thread from Sterling about idle problems...or was it from stuaull? I forget. Waiting for tune up parts, will knock that out tomorrow and then follow the guide for idle. Thanks again DD.

Slandd

Well I've been trying to get the car to idle. There is gas leaking from the carburetor. The last photo is the actual leak, I kind of zoomed out at first so it's easier to tell which direction I'm at etc. Thanks again all for any help.

rotordogg

iTrader: (4)

Accelerator pump, I think. You need to pull that car off and rebuild it.