Horrible exhaust smell in the car, usual fixes already done

[j260z]

here's another thought. is the smell an exhaust smell or more of a gas smell. the reason i ask is, if it is the latter, you could have a crack in the rubber filler tube from the gas cap to the tank or one of the vent tubes. those pieces are probably 31 years old and they have been known to crack.

[EvilRufusKay]

I considered getting a NOS bottle, filling it with O2 and attaching a mask. It would look like I was breathing Nitros and I wouldn't have the killer headaches and burning throat.

 

Seriously though I did lean out my fuel mix alot. That helped a bit.

[Guest bastaad525]

ROFL you know I told my g/f that same idea... to wear an oxygen mask or get like a periscope style tube that would feed fresh air to me. I've already been seen driving with my shirt up covering my nose and mouth, or driving with my head practically hanging out the window like a dog.

 

It's definately an exhaust smell, not gas. I do get gas fumes sometimes when I full tank it, but very briefly if at all. No cracked hoses back there I've checked them all out.

[Guest Nic-Rebel450CA]

I have been having the same problem with my Z. Just changed every gasket in the exhaust and intake and got rid of those leaks, but the exhaust still swirls back from the back of the car. I do have a much shorter tip on it then when I got the Z. I was actually considering making some sort of duct under the car to help force air around the tip towards the back of the car and out and away. Maybe even a tip with two pipes with air space in between and like an air horn on the outer pipe facing forward.

[Guest bastaad525]

If you come up with something that works let us know! I'm 99% sure it's not an issue with seals... I too think it's just swirling up around the car and coming into the windows. Even sitting at a light if I leave the windows down I can smell it really bad, when it's cold out... the smell just envelopes the whole car... even if you stand near the car anywhere near the back or sides, you smell it... no seal is gonna save me from thatm

[Guest Nic-Rebel450CA]

If you come up with something that works let us know! I'm 99% sure it's not an issue with seals... I too think it's just swirling up around the car and coming into the windows. Even sitting at a light if I leave the windows down I can smell it really bad, when it's cold out... the smell just envelopes the whole car... even if you stand near the car anywhere near the back or sides, you smell it... no seal is gonna save me from thatm

 

Yep, and as soon as you roll the windows up it goes away completely (you just roast from the heat)

 

I'll keep you updated, going to start the duct idea this week.

 

This wont help with sitting at idle, but it should help at any speed. I suppose if you wanted to go nuts then you could put a fan in the duct too

 

EDIT: I put a pic in my album of kinda what I am talking about. I am sure it could be made to look a bit nicer.

[Guest bastaad525]

yeah unfortunately even with the windows up it gets in there... for the most part it's okay but when it does get in it usually gets in a LOT enough to make you feel sick instantly.

[Guest Nic-Rebel450CA]

If it still gets in with the windows up then I would say that you have to have holes somewhere. Mine stops 100% as soon as I roll up the windows. I am really thinking of studying the airflow around the back of the car to see what the design problem is. I dont want to have an 8" long tip, I dont want to have a turn-down tip. I think that the problem has something to do with the shape of the rear of the car, the velocity of the exhaust flow, and probably has something to do with the fact that the muffler is at the very back (I would imagine that this causes the exhaust flow to be even lower).

 

 

By the way, can someone move this thread to the Exhaust forum? I think it is better suited there and would be a great resource to be easily found when we finally come up with a solution for our Z's

[VRJoe]

Check the exhaust system up front. It sounds like a leak around the turbo that's getting in through the seals in the firewall or the air intake. Check for leaks around the header and turbo. The fact that hard driving increases the smell points up front. Try covering the firewall seals with tape and covering the air intake grill also. If there's less smell you'll know that the problem is up front.

 

- Joe

[Guest bastaad525]

I know it's not the exhaust gasket leaking as we just replaced the head and used a new gasket... well okay so I guess i"m assuming but I dont know it may be coming from where the turbo bolts to the manifold or where the turbo bolts to the downpipe, I'll check those out.

[Clifton]

You would need a 2 foot long tip to get it out of the high pressure area behind the car. Did you check the tail ligh gaskets the inner hatch cover. Fumes can get it through the lock and enter through that.

[Guest Nic-Rebel450CA]

I think I am going to rent a fog machine and set it up in my car for an hour and see where the fog comes out

[EvilRufusKay]

I just got to work and I can't seem to remember what this thread is all about........................everything is sooooooooo hazy!!!!!! It's all like a dream. A really bad dream riddled with headaches!!!!

[Guest Nic-Rebel450CA]

I found the solution!

 

[EvilRufusKay]

Perfect!!!

 

I am surprised MSA doesn't sell one with a big Z on the back!!!!

[Guest bastaad525]

Heh seriously...

 

You know Nic you and I keep having the same ideas... I was thinking of doing something like that creating smoke from the inside and see where it comes out... think it'd be scary to find out though I'm sure it will come from 50 difference places

[EvilRufusKay]

I thought it was a good idea to, but what about the moisture? Some of those machines use chemicals to create the fog and that might F-UP my already F-ED-UP interior. and your right I probably DON'T want to know how many holes I have in my car. My rear sill is rotten on one side and the seal is completely shot, but I am afraid if I fix those things it will still reak. I have learned the faster I drive the less smog gets in the cab.

[Guest bastaad525]

ROFL

 

yeah if you go faster it stays out, but then when you have to slow down it catches up to you and if you've been on it long enough it will be BAD in the car.

[72zcar]

bastaad525,

Even though U replaced the rear hatch seal it is most likely the cause of the fumes.

 

Do this: park in a dark garage and throw a blanket on the rear window. Crawl inside the car in the back and have someone with a strong flashlight on the outside of the car go along the hatch seal...you will see light where the seal is not sealing properly.

 

Now: get some thin foam (the kind u buy at a hardware store with thay is self adhesive) and put it on the underside of the hatch where u see black caused by the hatch seal all along the bottom and about a foot up both sides. If the hatch wont close take a little of the sides.

 

see what that does, it worked for me and i was crying

[Guest rick458]

if you had the rear valance louvered would that help reduced the low pressure area behind the car and help with the fumes?