Z_lover

Hello everyone! I am getting a smell in the interior of my '81 280ZXT. I inially thought it was an exhaust leak being there were a few small holes in the muffler, but that has since been repaired and the exhaust is sealed (except at the tailpipe). I am beginning to suspect something in the fuel system/emissions control system. Has anyone else had a similar problem and could point me in the right direction as far as troublehshooting? I have a hard time describing the smell but it is nothing that I am familiar with in terms of burning oil or rubber.

audiofreak97

Hard to diagnose a smell without knowing what it 'smells like.' Is it a fuel smell, an exhaust smell, a gear oil smell, coolant smell, mildew, burning electrical...

Z_lover

Sorry for the lack of smell description. My best description would be hints of a fuel smell, but often more of sweeter smell than fuel. Definitely not coolant, mildew or burning electrical. It sort of makes my eyes water and dry out.

audiofreak97

Reading your other thread about running rough when starting the engine after warm up;
Could be running rich, Burning coolant, Or maybe you have an injector that is leaking? Each of those would cause both an odd smell (depending) and the eye problems.

BlueKitsune

I have this same issue and I know what it is.

Its your heater core leaking into the bottom of the air control box under the dash. Sense coolant is a almost sickly sweet smell to it. Its mixing with the dust in the air to make such a weird scent as well

Z_lover

Blue,

I wish I could say this is the problem, but I have never had to top off my coolant system with a single drop so I do not have a coolant leak. I think audiofreak has a good idea with the engine running rich or a leaking injector. Does anyone know what typical fuel mileage is on a 280ZX Turbo w/ a 3-speed auto? My last tank of gas was an average of 16mpg with about half city & half hwy driving. This has always seemed to be a bit low in my opinion.

What is the best way to troubleshoot a rich engine or leaking injector?

Naticon

These cars always smell like something. I tend only drive with the windows down or tops off.

Z_lover

This smell is with the the tops off and the windows down!

audiofreak97

Could the smell be coming from the back end of the Z? Maybe you have leaking fuel line at the tank or the o-ring on the pickup tube may be leaking gas/fumes?

I had both a cracked line and a bad o-ring and the gas smell burned my nose to a point where the it was just a dull odd odor... The smell wasn't bad with the windows up, but as soon as I cracked a window it was bad. Just throwing out another idea...

Z_lover

Possibly, that would be a good place to investigate. It seems to me that this would occur move often when the vehicle is moving being fuel is "sloshing" around. Is there any good way to find a leak while the vehicle is standing still? Even the fuel odor leaking would be difficult to track down, short of using a lighter until you find the leak and go "boom"

BlueKitsune

I never had to refill my coolant either. Its a VERY small seep so it wouldn't be noticeable as a coolant loss but it would in the smell.

Or your back hatch seals are bad and your getting exhaust fumes pulled up into the front. I put an turn down tip on the end of my exhaust before the bumper ends and that helped with exhaust issues.

If its a fuel leak it will smell like your at a gas station filling up your Z lol And you will notice the leak when the fuel pump is running. unhook your oil pressure switch and turn the key on, the fuel pump will constantly run and you can look around for leaks.

uh might also want to check the charcoal canister and its lines to make sure their ok sense they pull the fuel vapors out of the gas tank.

Z_lover

Thanks for the ideas Blue!

My hatch definitely does not seal very well. I have replaced the muffler and put on a longer tailpipe extending beyond the bumper, but this has not made a change in the smell.

The fuel leak and charcoal canister sounds like a likely culprit. Where is the oil pressure switch located at to disconnect? Also, where is the charcoal canister & how do I troubleshoot it for leaks?

Z_lover

I’ve posted about this before, but never fully resolved the issue and I’m getting very irritated about it. I get an exhaust smell in the cabin, especially when the windows are down (which is normally how I drive it). I finally took it in to an exhaust shop and had all new exhaust ran starting at the downpipe all the way out the back, including a new cat and Flowmaster muffler. The tailpipe is even sticking BEYOND the rear bumper to better aid in exhaust exit the underbody.

Got the car back and I’m STILL smelling exhaust in the cabin!! Took it back and had it checked over again and no leaks that they can find.

Now I realize that there is rust in my floorboard pan/stiffeners like all S130 suffer from that could use repair, but as far as I can tell and the exhaust shop, there are zero leaks in my exhaust (turbo/exhaust manifold to tailpipe). How in the world am I getting exhaust in the cabin at speed (30 mph)?? Does the underbody create some odd reverse vortex to funnel air up forward and up through the lowered windows?

If anyone has any ideas/theories, I am all ears!

Zdon

The main culprit is from the rear hatch seals and quarter glass window seals. That's the best i can tell you. Good luck.

NismoPick

Merged w/ previous thread so we don't have to re-hash what has already been done / checked.

So, did the exhaust shop use clamps? Band clamps or U-clamps? Or welded?
Are you using a cat?

A similar read: https://www.zdriver.com/forums/240z-...ntinues-22919/

Z_lover

Thanks for merging NismoPick. I couldn't seem to find my old thread.

The exhaust is all welded connections and I am running a cat.

@Zdon
Do you have any suggestions/tips on how to seal the hatch and/or quarter glass? It looks like a new seal kit is only $40.

FricFrac

Quarter windows just use a tube of window sealant - easy peasy (but messy)

On the 240Z's there is a weird vacuum effect that at speed the exhuast will travel up a vacuum section along the side of the car and into the window. That is fixed by an longer exhaust tip (which you've already done) and/or a rear spoiler to eliminate the vacuum effect.

Does your exhaust shop have a gas sniffer? Probe around the running exhaust to find the leak...

Z_lover

Exhaust shop did not have a gas sniffer. He was using some type of stethoscope to inspect for leaks. The one comment that I failed to mentioned was that after the cat was installed, the smell seemed to change to have more of a "metallic" smell which leads me to believe that the exhaust smell is coming behind the cat being the exhaust is being heated up more now. Keep in mind that it is all new exhaust from the downpipe back.

I did find a gap in the hatch seal this weekend that I need to close up.

Aeleven

Check the Plastic holders on the Fuel injectors. They tend to crack and leak fuel.