Hello,

I have a 93 RX-7 that I recently picked up and I noticed that it has what I believe to be an exhaust smell coming from the back of the motor by the firewall. I've noticed it smells the strongest immediately after turning on the car when cold and it's idling down. Once it's gotten up to temperature the smell is minimal but if I sit idling long enough the smell gets noticeable.

If I place my hand between the UIM and firewall I can also feel an air draft back there, since the car doesnt have a belt driven fan I dont know where the air is coming from. I thought the only thing that could create air back there would be the flywheel but it doesnt look like it's exposed.

I also dont think the problem is a fuel leak because if I let the car sit all day in a closed garage I do not smell gas when I come near the motor or anything. However I cant really tell the smell apart too well since the oil smells like gas too due to the two mixing.

Another detail to point out is that if I turn on the heater or just the fan it sucks in the smell into the cabin. So now I cant use my heater during the colder days without having it suck in fumes.

I dont have any idling issues, and the actual exhaust itself at the back smells clean.

I do seem to have an oil pan leak, while I was changing the oil I noticed that the under belly that covers the transmission has a nice thin coat of oil on it, so it's possible that it could be burning up oil if it's making contact on something hot down there, but I dont smell it from the passenger side. I only smelly it from the driver side but mostly from the firewall area.

Anyway I tried to provide the most detail I could in hopes someone might have a good idea what is causing the smell..

Thanks!

 

While its running, do you by chance hear a "pst pst pst" sound? Nonstop that is

 

I have not heard any that I can make out. The motor is pretty quiet with no abnormal sounds.

 

If you're still running the air pump and egr, I'd would suspect something related to the secondary air injection/split-air bypass etc. Page F-115 in the FSM. http://www.wright-here.net/cars/rx7/93_manual.htm
Might be something as simple as a blown gasket or loose hose. Have you looked under the car?

 

Thanks for that suggestion, I will look into it. Looking at pg.115 it seems like it ties into the rats nest so I'll have to dig in there to take a good look at the hoses. But it may be what's causing my issue. I'll compare the manual to the engine bay when I am at home to see if I can find anything while the UIM is still attached, otherwise I'll have to wait to dig in there until I order replacement manifold gaskets and the new vacuum lines.

 

I haven't looked under the car very much, I crawled down there while changing the oil but didn't see much else. What type of gasket would be typical of this issue?

 

So I attempted to look around the manifold area today but I didn't have much luck. I think I'll have to wait until the weekend to really take my time and check things out.

 

So today I hooked up a temp boost gauge so I could see what the pattern is and its registering I have a boost spike/creep of 16psi then it drops to the 8 - 10 pattern. I thought I was suppose to hit fuel cut by 12-13 psi? There's zero mods done to the car, it is bone stock.

 

So after some researching through the sequential turbo FAQ's I saw that it mentions if there are boost spikes then it's likely the turbo precontrol line has come unplugged and that sounds a lot like what I'm experiencing. I see that the precontrol solenoid is below the manifold and from there it runs a vacuum line to a hard line that later has another rubber vacuum line plugging into the turbo. So I'll be tracking down the line to see if it is unplugged.

Meanwhile I haven't yet tracked down the smell.

 

So I was really sure that was gonna be my problem but I tracked down the lines for both the Pre Control actuator and the Wastegate Actuator and both are plugged in. Below the manifold they are both hooked up really tight onto the hard lines that run down to the bottom and from there I followed them to the two actuators on the primary turbo and they are also hooked up on there. So now I don't know why I am hitting a boost spike of 16 on the primary turbo. Any ideas?

I'm going off of the troubleshooting outlined on this page http://www.autosportracetech.com/RX-...leshooting.htm that says if either of those two are unplugged then I would be seeing high boost spikes on a stock vehicle.