Another smoking FD...
 

Hi guys so my 1993 RX7 is smoking from the exhaust and a bit from the engine bay. I cant figure out what the problem is and after reading many threads about smoke coming from the exhaust most times its coolant seals.

Anyway here are some key points about my RX7:

*The smoke does not smell like coolant
*The smoke is not thick
*The smoke is white/grey
*The smoke smells like a old muscle car/ a sports bike with a aftermarket exhaust
*The smoke is either oil or gas... cant seem to tell
*The smoke also comes out of the engine bay, from the back of the engine bay near the oil filter
*The car starts and runs without any issues or overheating
*The car has a very rough idle, does not settle down, the car hovers around 1K-1.2K rpm
* The car also "drops flat on its face" when it reaches 4k rpm (It doesn't accelerate nearly as much as is does under 4k rpm)

I have Changed the fuel pump and up next I will change the fuel filter.

Check for oil in the charge pipes, and play in the turbo's shaft bearings. Turbo seal failure is a common source of smoke as I'm sure you know.

Check your map sensor line.

I checked the hot side charge pipe and it had oil in it, the cold side charge pipe also had oil. Is this a sign of my turbo going out?
Do I need to remove the turbos to check shaft play or can I check on the compressor side of the turbo?

Also the previous owner said that the original Main catalytic converter got clogged from catalytic converter from the downpipe, to fix this he cut out the old main catalytic converter and used a generic "OBD II" converter. So with all that said could it possible that this would create the loss of power near 4K and not the secondary turbo being out?

I will check the lines tomorrow, do MAP sensors go bad?
The car has 100K miles on it, its fairly well taken care of with a fair amount of paperwork for maintenance and parts changed .

Does the loss for power near 4k and rough idle indicate something with the MAP sensor?

One thing I also wanted to mention is that the car would consistently make "popping" sound like it was misfiring/backfiring when ever I let off the throttle, now if the RPMs were lower than 2k it would not make that popping sound. If I were to rev about 2k it would make the popping sound. About a day later I replace the Fuel Pump. After I replaced the fuel pump I did not reconnect the Bose acoustic wave subwoofer in the hatch. Right after I finished the install of the pump and started the car up I noticed that it wouldn't make the popping sound nearly as much but when it did my god was it much louder. After a few days the misfiring/backfire completely stopped when I would let off the throttle. A few days after that when I started the car is started to smoke on start up, when it warmed up the smoking became a lot less and after 20 minutes of driving It completely went away. Now I have not driven the car since then because I want to fix the issue. The car still starts, but after about 5 minutes of warming up it still smokes. I have also noticed the vacuum dropping from 15 to 14 to now sometimes near 13.

Other than the rigged up exhaust and a aftermarket AST the car is completely stock.

non-working pcv will pressurize the crankcase and cause smoking. next time it is smoking try removing the oil filler cap

the decel popping is caused by miscalibrated throttle position sensor

As far as the smoking under the hood, check the oil metering pump lines at the oil squirters. Mine smoked like this and made a HUGE oily mess under the intake manifold (and everything below that!) from a broken tube at the squirter.

I suggested the map line because because it causes all the synotoms you're having. It's the main sensor the ecu reads to tell it what to do. I recently left off my map line in my haste and had all the symptoms you have, even smoking in the engine bay and bag out of the exhaust, the ecu didn't know what was going on. I didn't try going past 4K with it running like that however.

So if I'm clear, the previous owner removed the cats and is tricking the ecu with a simulator basically? Do you have cars at all? If not that would be the biggest cause of your gurgling on decel unless you tune to get rid of it.

Also list every mod your car has so we can help better

Hey guys so I was taking parts of the car to check the MAP line and to check the turbo for shaft play. In doing so I noticed that the previous owner tried to "redo" the vacuum lines and messed it up really bad. I Literally found some lines that were not even attached. Anyway thanks for all the help guys, looks like I will be redoing the vacuum lines following
DaleClark's guide. Ill update this post just in case someone is having the same symptoms as my car once the vacuum job is done.

Alright its been a while but I can now say that the previous owner was a noob. Dude straight up did not replace a oil line which was causing oil to spill all over the exhaust manifold and headers....

https://cimg5.ibsrv.net/gimg/www.rx7...bb3f5d3419.jpg

This shows that the most unreliable part of a RX-7 is the owner

https://cimg6.ibsrv.net/gimg/www.rx7...c6d8de3ca0.jpg

This shows that the most unreliable part of a RX-7 is the owner

Looks like he tried to rig up that oil metering line as well, it was broken and he tried a piece of vacuum hose and a wire tire. That ain't ever gonna work.

As stated, owners doing sloppy work is the FD's worst enemy. A new $20 OMP line and this would never have been a problem.

Dale

Lol that's an awesome repair. Top notch work. Good find.

As for the popping, that is notorious with an aftermarket exhaust on a stock ecu. Does the cat have an air pipe hookup?