M3 E36 4door fuel smell when interior fan/aircon is on

[Coupe Turbo GP]

Hi guys,

I have read about other related topics on the infamous fuel smell issue on the e36's.

Mine seems different though. I only experience this problem when the interior fan/aircon is on while driving slowly in traffic or at a red light. If i'm on the highway and the aircon/fan is on there's no fumes. When driving with the aircon/fan off in all conditions there's no fumes.

Any help will be highly appreciated.

 

[Coupe Turbo GP]

Nobody? :tease:

 

[Lysis]

Does your idle change at all when you switch your aircon on? There should be a slight dip in idle as the compressor engages and the computer corrects for the extra load. If your car doesn't do this, then your fuel smell might be coming from a faulty fuel tank vent valve.

 

[Coupe Turbo GP]

Does your idle change at all when you switch your aircon on? There should be a slight dip in idle as the compressor engages and the computer corrects for the extra load. If your car doesn't do this, then your fuel smell might be coming from a faulty fuel tank vent valve.

Yes the idle does change. It does take a while for the aircon to kick in though, Yeah there's a few small things that need to be sorted out lol!

After a drive today I could smell fuel while standing in front off the car when I went to open my garage. Is it possible that there could be a fuel leak some where under the engine bay. I also wanted to find out, if there is a perished or damaged vacuum or breather pipe could it cause this issue?

I will get the fuel vent valve checked as well. Thanks

 

[alexzz]

has the car been standing for a while?

 

[Solo Man]

On two of the three E36 cars that i had there was a problem with the plastic/nylon "casing" of the float cracking along where the pick-up pipe fits. Take the rear seat bench out, lift up the rubber layer underneath the seat where the cutout is (sort of half moon but slightly elongated) and lift up that section of the rubber layer. Underneath you will find the metal cover with four screws. Undo the screws and lift up the cover. There you will find the float assembly/nylon cover i was talking about. See if you do not see petrol on the cover. If you do and you closely you will see that it most probably leaks from a crack in the pipe going upwards. I fixed mine with Qbond and baking soda. Buy a new bottle of Qbond (about R15) and bum sum baking soda from the wife/gf. Clean the whole area thorougly, if you have a small file try and file a groove into the crack and apply a little Qbond on the crack. Then apply a nice layer of baking soda and then dose the baking soda in Qbond. Be careful as the smell/smoke burns the eyes. Leave to dry and it should be fixed. Note that there are two cutouts under the seat, the one is for the float and the other one for the pump (i think). If you should need a new float, i have one brand new from the agents that i did not use as i fixed mine this way. Just my 2c for what its worth.

 

[Coupe Turbo GP]

has the car been standing for a while?

No bud the car hasn't been standing.

---

On two of the three E36 cars that i had there was a problem with the plastic/nylon "casing" of the float cracking along where the pick-up pipe fits. Take the rear seat bench out, lift up the rubber layer underneath the seat where the cutout is (sort of half moon but slightly elongated) and lift up that section of the rubber layer. Underneath you will find the metal cover with four screws. Undo the screws and lift up the cover. There you will find the float assembly/nylon cover i was talking about. See if you do not see petrol on the cover. If you do and you closely you will see that it most probably leaks from a crack in the pipe going upwards. I fixed mine with Qbond and baking soda. Buy a new bottle of Qbond (about R15) and bum sum baking soda from the wife/gf. Clean the whole area thorougly, if you have a small file try and file a groove into the crack and apply a little Qbond on the crack. Then apply a nice layer of baking soda and then dose the baking soda in Qbond. Be careful as the smell/smoke burns the eyes. Leave to dry and it should be fixed. Note that there are two cutouts under the seat, the one is for the float and the other one for the pump (i think). If you should need a new float, i have one brand new from the agents that i did not use as i fixed mine this way. Just my 2c for what its worth.

Thanks for the info bud. I had a similar problem before that you speak of where they didn't tighten the plastic/nylon casing properly after fitting a new fuel pump. This is not the issue at the moment. These days the smell is more distinct when standing in front of the car when its idling and the car is hot. I just need to find the time to have it checked out.

 

[328ii]

On E36s the fuel lines join the fuel rails right behind the fan
My guess is there may be a slight leak there - top & rear of engine
Be warned - It is a k@k place to get access to - see fuel pressure regulator

8?>

 

[AndreasSA]

In most cases its the piping/hoists behind the engine towards the passenger room where the small gap is. There are some possibilities for leakages. Check it properly, it starts first dropping and some weeks later you have a lake underneath your car. You need a torch to see it properly....

Be careful a bit because the fuel is dropping directly onto your exhaust underneath!