Hi guys,

I noticed yesterday a periodic gasoline (not exhaust) smell in the cabin while driving with the windows down.  With the windows up, the smell disappears.  I opened the hood while the car was running and didn't smell any gasoline then got under the car near the fuel pump and didn't smell it there either.  I thought it could be the vapor tank hoses but if that was the case, I'd smell it in the cabin all the time I'd think.

I can only smell it while driving with the windows down.

 

Any ideas?

 

EDIT: I started it and sniffed all over the engine bay and it seems to be coming from the passenger side firewall area (near the battery).  I'm guessing it's being blown back there by the fan.  I tightened all the fuel line hose clamps (which I was able to tighten maybe a quarter turn) but the hoses looked fine.  I checked my carbon canister's filter which looks brand new.  Any other spots I should check?  I really only smell it while the car is running.

Edited May 16, 20214 yr by chaseincats
additional information

Check your fuel filter and fittings for (if you installed one) your inline fuel pressure gauge.

22 minutes ago, rcb280z said:

Check your fuel filter and fittings for (if you installed one) your inline fuel pressure gauge.

The fuel filter and lines are brand new and pretty tight on there (no pressure gauge but I may get one in the future).

Carbs or EFI?

If carbs, it could one or more is venting an overflow of fuel in the carb bowl.  Debris can hold the needle valve open, or may have lost a float to old age.

If EFI, it'd be obvious if a fuel hose was leaking since it's at the same relatively high pressure all the time.  If a hard line is cracked, perhaps it only weeps when the motor moves on accel/decel.

Edited May 16, 20214 yr by ETI4K

Back in the 70's every car smelled like gas, it was normal.   Mmmmm, leaded gas, I miss that smell.

OK some thoughts for you to consider:

On mine I used to get this a lot. The PO bless him, had forgotten to do up the jubilee clips from the breather pipes at the rear of the car, behind the trim.

When the windows are opened, we create negative pressure inside the car and it sucks though any orifice at the rear of the car. This was pulling in escaping fuel smells.

Secondly, as already suggested, your passenger side has all the fuel coming into the engine bay, so if you are smelling it there, then that’s a good place to start to look for potentially damaged hoses. One Z club UK member found that his engine bay had a “mist” hovering over it. He then was horrified to discover his one year old braided fuel lines had perforated due to ethanol damage.

Thirdly, sometimes the carbs can have a sticking valve in the float chambers and be leaking fuel through the overflow pipes or through the jet area or both.


Make sure you carry a small fire extinguisher / blanket in the car. You’d be amazed how quickly fuel vapour can catch !!!!

2 hours ago, ETI4K said:

Carbs or EFI?

If carbs, it could one or more is venting an overflow of fuel in the carb bowl.  Debris can hold the needle valve open, or may have lost a float to old age.

If EFI, it'd be obvious if a fuel hose was leaking since it's at the same relatively high pressure all the time.  If a hard line is cracked, perhaps it only weeps when the motor moves on accel/decel.

It's EFI.  I'll try to start it in the garage and look under it for wet spots on the lines.

2 hours ago, AK260 said:

OK some thoughts for you to consider:

On mine I used to get this a lot. The PO bless him, had forgotten to do up the jubilee clips from the breather pipes at the rear of the car, behind the trim.

When the windows are opened, we create negative pressure inside the car and it sucks though any orifice at the rear of the car. This was pulling in escaping fuel smells.

Secondly, as already suggested, your passenger side has all the fuel coming into the engine bay, so if you are smelling it there, then that’s a good place to start to look for potentially damaged hoses. One Z club UK member found that his engine bay had a “mist” hovering over it. He then was horrified to discover his one year old braided fuel lines had perforated due to ethanol damage.

Thirdly, sometimes the carbs can have a sticking valve in the float chambers and be leaking fuel through the overflow pipes or through the jet area or both.


Make sure you carry a small fire extinguisher / blanket in the car. You’d be amazed how quickly fuel vapour can catch !!!!

Definitely - a fire extinguisher was one of the first things I bought when I got the car years ago haha

Sorry, I did not close this thread.  The issue was the clips around my new fuel filter which were tight but apparently not tight enough.

This topic never goes away, after all you own a Z.🤣

Just been out for a blast in mine and being 27°c with 85% humidity @22:00, I had the windows down, listening to the warble of the L28. Two things happened:

1. I had knocked off the rubber hatch seal and was sucking fumes - so now I feel light headed and have a head ache. Definitely worth getting it sorted, well done you! [emoji106]

2. My ears are ringing like I’ve been to a rock concern!! (And I still have the quietest of all, “Street muffler” on the car!)

4 hours ago, AK260 said:

Just been out for a blast in mine and being 27°c with 85% humidity @22:00, I had the windows down, listening to the warble of the L28. Two things happened:

1. I had knocked off the rubber hatch seal and was sucking fumes - so now I feel light headed and have a head ache. Definitely worth getting it sorted, well done you!

2. My ears are ringing like I’ve been to a rock concern!! (And I still have the quietest of all, “Street muffler” on the car!)

Get your cabin fan going - that will equalize the pressure and push the fumes out.