exhaust smell

[Ramses]

Hey guys,

Thanks for all your help on my previous posts. I am still trying to tackle the smell that I get only when I roll down the windows. This is what I have done thus far: Replaced all rubber...seals, grommets, all penetrations in cabin. I did a smoke test in the cab and after replacing the seals in the window channels, I have found not one leak in the cab. I took her out yesterday and when I got home, I smelled like exhaust.

I have a couple of questions. How far out does the tail pipe need to extend from the rear bumper to help eliminate this problem? I have also read that I should adjust my SU's. Is this correct? Why should I adjust my su's if they are running pretty well...no backfiring, starts right up, timing is dead on.

I removed the dealer installed AC and I have to drive with the windows down, because it is really hot in Houston. I will not try to attack this problem until after I replace my struts, springs, wheel bearings, front end or rack and bushings...I will be doing this during the Memorial day weekend.

I am really starting to get perplexed. Thanks in advance for you information.

:stupid:

[Bonzi Lon]

May I suggest as an "EXPERIMENT ONLY" to get several scrap lengths and bends of exhaust and put on what you have. Try running curved down fully behind bumper (street sweeper), curved pointed to the curb, straight to extend beyond bumper different lengths. I know, it may look ghetto during this time. but you just may hit on something. I know you have had some problem with this so just trying to throw anything out there.

Bonzi Lon

[DaveN]

The side winwows are in a low pressure area -- even lower than the back of the car, so you will get exhaust odor pulled back into the car with a window down if there is ANY opening from the area of the car's wake to the interior.

You can keep the windows up (or just cracked with the dash vents open /and or the heater fan on high), or become a fanatic about finding and sealing every crack, hole, etc. in the back 2-3 feet of the car, including underneath and in the spare tire well. Making sure the hatch and taillight gaskets seal is just a good start. There are also several gas tank vent hose and wiring harness penetrations, some in hard to see spots, that were not completely sealed at the factory, and you may find some small unused screw or bolt holes, or a bad/missing rubber hole plug. Good luck.

[AndysPlit]

Extending your tailpipe will make a difference. It worked for my 78. It just needs to come up to the edge of the bumper.

[justaZcarguy]

I recently battled this and was almost beat.

Two other places that I would check would be the tailgate portion below the window, I had fumes being sucked in thru the tailgate latch system and breaching past the vinyl peice there, I put weatherstripping around that and sealed it.

The other place is where the body and chassis come together at the rear of the rear quarters. This is best spotted from either under the car or by removing the rear plastic covers and looking for daylight in the corners.

That was a tough place to spot...

Like mentioned, the tail light gaskets are a popular culprit also.

I would suggest that you do a search on the fumes issue as there have been several threads posted.

Good luck!

[DougN]

I have the same problem on the '73. I also have an exhaust tip that is short and does not extend past (or up to) the rear bumper. One of these days I plan to get it extended, as I beleive that it is the culprit. I would love to know if you extend yours and it fixes the problem! :classic:

[AndysPlit]

It has for me. The only times I still get fumes is when I slow down or stop. But, it is MUCH better than it use to be.

I have the same problem on the '73. I also have an exhaust tip that is short and does not extend past (or up to) the rear bumper. One of these days I plan to get it extended, as I beleive that it is the culprit. I would love to know if you extend yours and it fixes the problem! :classic:

[CoastGuardZ]

I took her out yesterday and when I got home, I smelled like exhaust.

But that's one of the best parts about owning a classic Z!

Yeah, I've still got this issue to deal with but it's on the back burner since there are too many other things more important... I'm getting used to CO poisoning :sick:

Nate

[Carl Beck]

I didn't see it mentioned... but installing new hatch seals won't necessarily result in a seal being formed between the hatch lid and the body of the car. You have to assure that the hatch is properly adjusted so that it does in fact compress the rubber seals on all surfaces.

I usually put a dollar bill between the hatch seals and the hatch lid ... close the hatch lid - then pull on the dollar bill to see if it's held firmly in place, or if it isn't. If it isn't, you can still get exhaust gases sucked in through the gap... even if it is water tight...

FWIW,

Carl B.

[Ramses]

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?

[1 Bravo 6]

My Zed came fitted with a tow bar which I very quickly removed, leaving a couple of holes in the spare wheel well. That was a STRONG attraction for exhaust fumes.

You say that when driving with the windows up there's no exhaust fumes. Possibly because there's no circulation of air at all.

I'd be inclined to try Carl's dollar trick and if that doesn't show the cause of exhaust invasion, I suggest removing the plastic panelling in the back and checking out the wheel wells for signs of daylight. What about the tool boxes. Ensure that the tail lights are sealed properly into the body. Heck mate, check everything again but, if the S.U's are properly tuned, running well and giving good mileage, I doubt if playing around with them is going to solve your problem.

Rick.

:devious: :devious:

[ddezso]

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..