exhaust smell

[MikeW]

Refurbished SU's that were properly balanced and synched with the right air/fuel mix did more for my exhaust problem than anything. My wife will even occasionally ride in the car with me now..

While I agree that properly tuned carbs will help with the exhaust smell my concern is that making it smell better might lead to a false sense of security if the exhaust is still getting in the car. Think of the unburned fuel like the rotten egg smell added to natural gas; it's lets you know you've got a leak. Carbon monoxide has no smell so that may still be getting in.

[AndysPlit]

The early Z's have a slight flaw concerning the aerodynamics. You are still getting fumes beacuse of this. That's why extending the tailpipe will improve your situation. The extension will more or less break free of how the air flows around your Z.

This is what I have learned from my Z shop. Of course replacing all of the seals and all that helps too. Something interesting to note is that the 280ZX's were free of this flaw by simply adding a slight dip along the top of the hatch door.

Hey guys,

Thanks for the replies. I performed a smoke test. I have already replaced all the rubber seals on the car. I have replaced all the gromets on the car. I even siliconed some of the penetrations that looked like there may be some issues. I have such i tight seal on the interior, that it is difficult to shut the rear hatch or either of my doors with out the window being down.

That being said, I still smell like exhaust. I performed an experiment the other day. I went out without rolling the windows down, and I did not smell like exhaust. The culprit must be in either the tail pipe, which has an extension on it and stops just before the rear bumper or an the adjustment on my SU's.

Any Suggestions?

[ZCCOR#109]

maybe a spoiler will pull things further to the rear, that is what they are suppose to do.

what about the firewall? do you have an exhaust leak from the engine manifold area that is leaking through the firewall?

[BuDavid]

ok that issue is making me feel really "blended in" the Z community!

I do also smeel like an exhaust tip after a 20min drive with a window cracker open..

but the sad thing is that I don't have a rear bumper that I can extend the exhaust tip to it:dead:

what the hell now? shall I wish a bumper on my birthday or just get used to enjoy breathing CO until I get violet skin color!?:hurt:

besides, I don't want that 280Z bumper back in place because I wont really feel good having a bumper that has half a kilometer of length behind me:cry:

is making a narrower exhaust tip a mart plan to do? in this case I'll increase the gas pressure which will force the gasses to flow further away from the car and will not be able to recerculate within the "air bubble" behind the car at higher speeds..

[=Enigma=]

That's not going to help and could even hurt performance depending on the engine size and the size of the existing exhaust piping. Somehow I don;t think having the bumper in place makes all that much difference in the equation anyway. Someone please correct me if that assumption is incorrect. I think addressing the leaks, extending the pipe, or adding a spoiler are the only real solutions here.

[AndysPlit]

According to my shop adding a rear wing or spoiler will not help. Anyway, that's what they have sworn by from their years of experience with Z's.

That's not going to help and could even hurt performance depending on the engine size and the size of the existing exhaust piping. Somehow I don;t think having the bumper in place makes all that much difference in the equation anyway. Someone please correct me if that assumption is incorrect. I think addressing the leaks, extending the pipe, or adding a spoiler are the only real solutions here.

[Mike]

The exhaust backwash can be reduced by extending your tailpipe beyond the bumper. I have mine pushed out about 1/2" beyond the bumper and it works great.

Here's a link to some conversations we had about exhaust tips in the past:

http://www.classiczcars.com/forums/showthread.php?t=24927

[zbane]

This thought may very well be entirely off base, but perhaps it's worth considering-

Have you checked the condition of your shift boot? I removed my center console/shift boot today (just to look), and it strikes me as a very easy area for leakage to occur. Mine (being a ZX) is rubber/plastic/whatever and seals very nicely, but if memory serves, yours is leather and leather(?)-so I would think it possible that if there were even a very small hole in your exhaust pipe, and you didn't have a good seal in your shift boot area, that this might be the culprit. Just a thought.

[KDMatt]

Also, what about your header/manifold?

The header in my Z is 20 years old (or so) and has developed a hairline fracture somewhere ... I can feel it but I can't pin it down, and all it's doing is spewing exhaust fumes into the engine compartment ... and probably not helping the smell in the cabin...

[Carl Beck]

Have you been under the car, and inspected the entire exhaust system for leaks? That should be done carefully every year at least.

FWIW,

Carl B.

[Ramses]

Thanks for the ideas about the exhaust tip and the exhaust lines. I do have a leak in the manifold and the tip does not extend past the bumper. I guess I will work on that during the summer. Not much fun though. The entire cab is sealed shut and tight. I have checked with all the fun little tips mentioned in this and other threads.

Thanks again.

[CANDYBLUE2+2]

I must chime in here as no one seems to have touched on the A/C removal issue.

Doing this leaves two large openings for engine compartment fumes of all kinds to get in. This could be some of what your smelling. I removed my A/C as well, and in the process of blocking the old access holes, discovered many other smaller holes that were plugged or filled with a screw, etc...

I'm not saying this will cure all your smelly problems, but it's certainly worth a look.

Keep in mind, these older style pre smog days engines all have there own smell unlike any of the newer stuff on the roads today. If I don't drive mine and blow out the gunk from time to time, it'll run you out of the building if left to idle in place for a couple minutes.

Good luck with the fix and let us know how of your results.