Faint smell of fuel

Technical Area Engine, Transmission, Exhaust etc
2

Hi guys

 

I only use my 5 at weeks, like am sure many people do, however when I first get in there is the faintest smell of petrol, but it is there none the less.

I cant see any signs of a leak, but would be grateful if any of you guys could give me some pointers as to where to look.

 

thanks

3

Hi Silverine

 Could you tell us more about your 5, which model and year will help?

Can you smell the fuel in the boot as well as the cabin; have you opened the bonnet and checked for the smell?

 Richard. 

4

Hi

Sorry have stupid of me!
It’s . Mk2.5 sport, no smell in boot or under bonnet.
Didn’t notice smell when I first got her as previous owner been a smoker and can still smell smoke however that fading now and get faintest petrol smell.

Thanks

5

Engine smells might be due to a split rubber gearshift boot (under the leather/vinyl one). Also, the fuel tank vents into an activated charcoal canister, by the coolant expansion tank. Periodically, a solenoid purges vapour in the canister to the inlet manifold (this system is designed to reduce emissions). If there is a fault in the purging system, the charcoal can become saturated, and there will be a petrol smell.

The petrol tank has a 10mm drain plug, closest to the passenger side. This can leak, but usually only if someone has previously tried to drain the tank, and not replaced the crush washer.

6

Another place to check is the sealing on the fuel pump/sender panel. If this has been disturbed and not re-fitted properly it could be the cause

I have just changed my fuel pump, and on the second hand pump/ sender unit I fitted the rubber gasket had moved away from the retaining screw holes so I had to push the screws in to hold the gasket in place as I dropped it back in the tank.

I would leave this one until you have checked other things though as the rear deck carpet, and wind blocker need to come out to get at the access panel…

7

Hi Silverine. I also sometimes get a faint smell of fuel in mine but all i need to do is to take the petrol cap off as for some reason a bit of pressure builds up especially when weather is warm taking cap off releases the pressure ( obviously put back on after pressure is released ) and stops the faint smell. Hope this helps no harm in trying it first ok .

8

Hi

Thanks for the replies, the smell is also apparent in the boot, if anything slightly stronger.
Will try releasing the cap from the fuel cap first, as it stood all week this may well be it, and it the easiest to try first.

Thanks

9

 

Thats normal; they all do that.

 

The NB is basically the same as the NA:

 

http://revlimiter.net/blog/2012/07/how-to-eliminate-miata-gas-fumes-i-hope/

 

Your symptoms are still consistent with a fault in the fuel vapour EVAP system, but as pointed out, also a dozen other things.

 

This is the layout on a NB; what is labelled as a catch tank is a charcoal canister

 

1056×804 33.1 KB

 

If this system is faulty, it will lead to a saturated canister, and fuel vapour will just bleed through the numerous rubber-on-metal joints.

10

"no smell in boot or under bonnet.”

“ the smell is also apparent in the boot”

 Little confused here, which of your two above lines is accurate?

 Richard.

11

Hi

I had not noticed it in the boot but looking into it I have now noticed it in the boot.

Sorry for the confusion

12

I had a Mk1 that had a faint smell of petrol around the rear, nothing obvious that was leaking. It wasn’t present all the time so I put it down to pressure build up in the tank, as above. Couldn’t smell petrol when the car was outside, only occasinally when parked in the garage.