Exhaust fumes in cabin solved!!!

[73 240]

Does this reduced back pressure have any negative effects on the engine life/performance?

Brad 73 240Z

[Rocket88]

My son and I started working on the back of his Z.

We took the tail lights out of the car, I thought maybe the seals were dried up and no good.

To my surprise I found the driver's side reverse light wire looped between the seal and the body.

The backside of the tail light housing was all black, you could see exactly where exhaust was being sucked in.

It was litteraly the smoking gun!

We also found a small rust hole where the drain plug is on the antenna side.

The seals are good, so a little rust repair and careful re-installation of the tail lights, fingers crossed most of the fumes should be gone.

[Z train]

My son and I started working on the back of his Z.

We took the tail lights out of the car, I thought maybe the seals were dried up and no good.

To my surprise I found the driver's side reverse light wire looped between the seal and the body.

The backside of the tail light housing was all black, you could see exactly where exhaust was being sucked in.

It was litteraly the smoking gun!

We also found a small rust hole where the drain plug is on the antenna side.

The seals are good, so a little rust repair and careful re-installation of the tail lights, fingers crossed most of the fumes should be gone.

Rarely do you find a "Fuming gun" like that.But don't stop there,make sure every thing on the back of the cabin is"tight".

[Rocket88]

...fuming gun

The hatch seal seems good, I've been taking a sheet of paper and closing the hatch on it.

Went all around the hatch like that and it is very difficult to slide the paper out so I'm keeping my fingers crossed.

We've got the fual tank out as well.

The evap tank is going and we are sealing up all the holes left over as well as replacing all the grommets in the back of the car.

[argniest]

I am glad I found this thread too. Now its added to my long list of things to do. I find it very interesting (as mentioned above) that even a good running engine, still can produce this exhaust smell in the car. Because that is my main complaint about driving my z car. When I rolled down the windows... I get an exhaust smell building up in the car. In fact if I had a coat on it, I could take it off, and walk inside and the coat actually *stinks*

I saw the thread about using the fog machine. I have one. So I will be doing that too. I really hope I can eliminate this problem once and for all. I never smelled exhaust on any other car I have owned. At least I am not the only one with this problem.

I cant imagine that new Z cars had this problem. I suppose it just started happening once they got *old*.

I dont have a stock exhaust on it. Previous owner changed it. I think its a monza? exhaust. It has dual tips on it and it sticks out maybe just a little past the back bumper. And I have back window louver, and side window louvers that I added. I may very well take them all off, and drive the car and see if the smell changes or is better or worse. The back louvers have been on car since 1978 (I see them on the original sales reciept that I have for the car). The side louvers I added myself. It just makes me think that the back louvers didnt cause this effect on the car. Its probably just bad seals all over the place.

It seems to me that Previous owner replaced some of the seals. I also checked various grommets and fixed/replaced a few of them.

Edited January 29, 2011 by argniest

[Walter Moore]

I cant imagine that new Z cars had this problem. I suppose it just started happening once they got *old*.

That is part of the problem, but the other part is that we are running unleaded gasoline in cars without a catalytic converter. The anti-knock compounds that are in unleaded gasoline apparently smell horrible, and without a converter to burn them off you get that characteristic stench. I have the same problem with my 1967 garden tractor. It didn't smell bad back in the 60's and 70's, but today you have to take a shower after using it for any length of time at all.

[argniest]

Wow that is really interesting about the unleaded gas, and the old tractor. From what I know, only the California cars have the catalytic converter on them?

But does that mean every person on here (non california) with a decent running Z car, has a fumy stinky exhausty kind of a smell coming out of their tailpipes?

My two 99 chevys dont have any abormal kind of smell to them. But I suppose they both have catalytic convertors since they are 20 years newer almost.

[madkaw]

Well I'm going to tag on to this older thread because I think Derek had the best idea for trouble shooting this issue. I had actually bought a fog machine over a year ago when they were cheap(after the hallowen holiday). It really is a cheap, fast clean way to diagnose the exhaust fumes.

I tried the "suck" method first, but it left too much to question. Inside the car with not much room to move around and it being dark, it was too hard to tell where the fumes originated from.

Now the "blow" method was much better. It really only takes a couple of minutes to set things up and start trouble shooting.

What I found and yet to be fixed, is that I have a lot of air moving thru the latch assembly. It looked like a steam engine coming out of there. Perfect spot to suck up those swirling fumes around the back. I haven't finished examining everything yet, but the only way fumes have access thru this point is by leaking around the vinyl panel on the hatch. The low pressure in the cabin must be sucking air around this panel(which is NOT air tight-mine anyway) and thru the hatch assembly. It would seem to me that the easiest fix here would be to seal the hatch panel by sealing some plastic sheet behind it-agree?

I also noticed smoke around the left tail light , where some previous bodywork was done. Also noticed a lot of smoke out the pillar vents, but I think they are too far from the exhaust to be sucking anything in.

I will update as I try to fix these

[madkaw]

So all this time the majority of my issue has been the interior hatch panel not be sealed . It is night an day difference now that I have put plastic underneath the panel and sealed things off. It's not perfect but 99% better. So I am going to go along with all those folks that say it's nothing to do with exhaust tip length or lack of spoiler - it's an exhaust leak.

[Travel'n Man]

Did you use a shower liner? Got any pics?

[madkaw]

Just had some thick black plastic laying around and RTV'd it to the opening under the panel.

[madkaw]

Still enjoying clean air!!! This really has enhanced my Z driving experience. Windows down and 70mph is a joy. I did also find some small exhaust leaks in my exhaust system around some band clamps, which I removed and welded solid. I think I was smelling this when I was rolling up to a stop.

Though my hatch seal still shows leaks using the fog test, they are very minimal and I can't smell them. The remedy there might be an actual Nissan seal;0

So if you are dealing with smells, there is hope. first thing I would check is the hatch panel. Think about it, it's been there for 40 years and very possibly been removed at least once-probably by you---so seal it up!!