Hi all, I really need help on this please.
I just had my 1995 rx7 fd rebuild and the car runs perfect and feels strong, now I only drove it a couple of times but never got the chance to go anywhere far as the car starts with no smoke at all even when lightly taping on the gas but once I hit 3/4k rpm it starts smoking like crazy even at idle..
Once I stop for a couple of minutes and start the car when still warm it stops the smoking but then starts again when I start accelerating from 3k upwards.
It’s still on stock turbos and had it rebuilt with them working fine so I am assuming it’s not turbos and apart from that and correct me if I’m wrong but when I had a bad turbo it usually smokes like crazy at idle and kind of calms with acceleration and not the other way around.
could it be a leaking injector maybe? Thinking that is because the oil just smell of fuel again and just been changed and bad fuel smell, so much even my clothes stinks of fuel afterwards.
Thank you for taking your time to read my post and open for any help I could get cause we can’t figure out what it could be.

 

Check your oil level?

 

Thanks for the reply.
Yes all good and I changed the oil again just in case

 

recent rebuild ... perhaps the oil seals were put in the wrong positions?

 

Thanks for the reply.
It could be even though it was rebuilt at a professional shop that works on rotorys but these things could happen.
the only thing that we can’t figure out is cause I saw a rotary before with worn/bad seals and it kind of starts smoking even at idle.
in my case I can leave it idle till it’s fully warm and no smoke but when I hit 4k show starts and thinking maybe it might be injector cause to my knowledge at around 3800 rpm secondary injectors kicks in

 

Any help please would be great! while on idle looks gray to white smoke and while giving it gas it’s black. Pictures attached. took it to a tuner and tried setting the air to fuel and checked map sensor and vacuum leaks but no luck 😢 could it be a leaking/stuck injector?
also need to change oil for the tired time just by testing the car cause obviously it’s not drivable because the oil once again is full of fuel

 

What was done with the injectors during the rebuild? They will stick after sitting for a while, I test all mine with a 9v battery (injectors removed from engine) and have had pretty good luck cleaning and testing them this way. One of mine was stuck closed from sitting up a little while, I cycled it with a 9v battery and some lubrication until I had crisp clicks and clean flow through them. Fuel dilution can kill your new engine so keep an eye on it, good luck

 

Thank you for your reply.
Today I drained the fuel Thank cause stupid me left old fuel in the car.
I don’t premix since still running OMP. After fuel was drained and put fresh fuel the car ran nicely with no smoke till fully warmed but once it hit the normal temperature the car was stalling and could ref up at all and rpm was surging on idle seems like that al of a sudden car is running lean after warm up but still no smoke.
Spoke to my tuner and his thoughts is that is in need of a new tune.
so if that was the issue lesson was well learned not to use old fuel left in the tank… STUPID STUPID mistake

 

I would pull those injectors and have them clean and tested, in my opinion if it was a tune issue it would be more consistent with the lean condition or smoking. If you send it to the tuner with issues you could end up with a damaged engine if the tuner doesnt catch whats going on. Do you have a wideband, I assume you do since you stated it was running lean. The black smoke obviously as you likely know indicates a rich condition then now lean conditions just indicates to me injectors. I put a car back together and had a similar issues years ago before I knew better and it cost me an engine, I didnt have a wideband so I didnt really know what was going on, lesson learned.

 

You are absolutely right! I really don’t feel like going for another rebuild..
yes very strange first I had super rich condition then lean and no unfortunately I don’t have a wideband but as you sad it noticeable that having dark smoke to black means rich and then car bucking and barely responding to throttle and staying alive like it’s beginning for fuel and strangely when the car was fully warm when symptoms started.
After a day of looking at vacuum diagrams hoping a vacuum line went loose, I came across a hose with fuel written on it under UIM disconnected, I pulled it out to see where it’s coming from since I can’t see where it should go I saw that it’s coming from deep below the turbo solenoid / precontrol valve. I will post a pic below.
I may have to remove the UIM to have a better view of where it might connect.
Thanks again for all your help!

 

Hose is coming from deep below turbo solenoid
very close to fuel rail

 

Do you have any oil in your intake plumbing? Wonder if oil is passing through the turbos and into either the intake or exhaust and burning black/blue.

Take off the oil fill cap and smell it for fuel.

Do you have a datalogit for the car? Logs? And what map do you currently have on the car. I see you mentioned that you took it to a tuner.

I agree that you should have the injectors cleaned and flow checked. Worse case run a few bottles of Techron Fuel system cleaner through the car to see if that helps a stuck injector, although the black smoke leads me to believe oil is burning and not just excessive fuel.

 

It is often a new owner mistake to overfill the oil which then flows up the filler neck and down the breather tube to the front turbo. With the results you describe.

 

As iceman suggests take a look in you intercooler cross over pipe (coming from the Y-pipe and see if there is (a lot) of oil residue. This would be a symptom of oil getting into your turbo.

Check if the oil breather tube is still connected to the UIM and/or the intake elbow in front the front turbo.

Overflow oil could also be flowing into your UIM.

Many people route that breather tube to a catch can and seal of the ports to the intake elbow and UIM.

 

If the vacuum hose to the Fuel Pressure Regulator has popped off or is damaged or the solenoid that regulates the vacuum stops working the FPR will close. This will back up pressure in your fuel system and force more fuel through your injectors.

Is your car JDM RHD and srtill stock ecu?

If yes you should learn how to run codes and do that before digging around in your engine bay.