Well gang, here's a topic that's been beat to death...but let's give it another swing shall we?

I saw an old forum thread where a guy put a Halloween fog machine in his car and with all the windows up, turned it on which showed all the air leaks in the cabin.  Specifically, he did it to find where exhaust was sneaking into the cabin when driving with the windows were down.

I gave that a shot this evening and found that it is my taillight gaskets, but the strange thing is they are brand new from Motorsport.  We even removed the black trim surrounds and bolted them back to the body and you can see the smoke sneaking around the gasket edges regardless of how tight we make the bolts holding the gasket to the body.

The gaskets are reasonably squishy (I have no idea how gummy these are supposed to be but they are very pliable).  I did notice that the plastic housing has raised bumps where the mounting bolts come through which would mean the gasket wouldn't be laying flush in the areas between these bolt bumps, right?  Was I supposed to install these with gasket maker between the rubber gasket and housing?

Edited May 3, 20231 yr by chaseincats
added image

14 hours ago, Yarb said:

You’re probably don’t have a fuel pressure gauge installed after the filter to monitor pressure . I noticed on mine, fuel pressure would bleed down. Never interfered with starting even cold at 0 pressure. Builds quickly while starting. Check the fuel damper next to the pump. Probably going to need a mirror to really look at everything carefully or get an inexpensive endoscope camera from Amazon that’s blue tooth. Valuable tool.

Will do - I'll sniff around tonight.  I was thinking that I could probably pull the oil pressure switch connector and pressurize the system while it's sitting which should work.  With the taillight gaskets sealed, how would that smell be sneaking into the cabin though?

6 minutes ago, chaseincats said:

Will do - I'll sniff around tonight.  I was thinking that I could probably pull the oil pressure switch connector and pressurize the system while it's sitting which should work.  With the taillight gaskets sealed, how would that smell be sneaking into the cabin though?

Through a leak you haven't found. It might show up more with the other leaks sealed.

So here are some target areas:

Missing grommets for the fuel tank vent lines

Missing grommets from the wiring harness to the fuel pump/fuel sending unit

Missing bolt that goes through the body (with a change to aftermarket seatbelts

Bad/missing grommet for the throttle

Bad/missing grommets around the heater hoses or wiring harness in the engine bay

 

UPDATE: I blew through the vent hose that goes to the carbon canister and got a thick gas smell in the cabin.  I will investigate the vapor tank/hoses tonight.

5/23PM: Found/fixed cabin leak by replacing old style vapor canister hose clamps with belt clamps & confirmed leak under the car using a cigarette and hand pump through the vapor tank also sealed fuel sending unit access door with seal 'n peal.  Waiting on a new jack to handle under-car

Edited May 24, 20231 yr by chaseincats

Sounds like good progress!

One other thing to check... The grommet around the antenna drain tube. It's back there in the same corner as the end of the exhaust pipe. 

34 minutes ago, Captain Obvious said:

Sounds like good progress!

One other thing to check... The grommet around the antenna drain tube. It's back there in the same corner as the end of the exhaust pipe. 

Sealed that bad boy with some duct tape but thanks for the tip!

On 5/22/2023 at 9:58 AM, SteveJ said:

So here are some target areas:

Missing grommets for the fuel tank vent lines

Missing grommets from the wiring harness to the fuel pump/fuel sending unit

Missing bolt that goes through the body (with a change to aftermarket seatbelts

Bad/missing grommet for the throttle

Bad/missing grommets around the heater hoses or wiring harness in the engine bay

 

Checked all of those except for the fuel sending unit wiring harness grommet - any idea where that is?

Behind the passenger seat where the deck wall meets the floor board. The relay is mounted on the back of the seat rail support as well. Pull the carpet up you will see the harness.

Great job so far @chaseincats.  I was looking at Amazon and a smoke machine with no frills is only about $33.  Once I get time to actually work on my Z again, I plan to buy a smoke machine and seal it up tight.  It's amazing how many places exhaust can be sucked in.  Every grommet and seal will be dry after 50 years.

 

19 minutes ago, Jeff G 78 said:

Great job so far @chaseincats.  I was looking at Amazon and a smoke machine with no frills is only about $33.  Once I get time to actually work on my Z again, I plan to buy a smoke machine and seal it up tight.  It's amazing how many places exhaust can be sucked in.  Every grommet and seal will be dry after 50 years.

 

Definitely.  One thing I did was stick a bright light under the car then sat it on the tank shining up towards the underside to see where light shone through then glopped some weatherstrip sealant on it to close under-car leaks

Update: So I just went under the car and looked around, tightened hose clamps, etc.

All the hoses under the car looked newish with modern belt-style hose clamps except for one which I yanked off (image below) which will be replaced tomorrow along with belt clamps so I think we're in business here.  I also found one screw hole that was missing a screw so I dug one up strictly to plug that leak hole.

Forgot one hole: There's a drain hole for the power antenna. It's near the exhaust.