Getting no "Pshhhttt" sound when i release the fuel filler cap

[TUFFTR]

Sounds like a stupid thread title but yeah It's true.

1991 Diamante, DOHC 24v Automatic.

Been getting HORRIBLE fuel consumption of around 16-17L/100k's which equates to 300k's from 50+Litres of 98 octane

What could I start looking at or testing to determine if there is indeed a fuel pressure related problem.

FPR? Any tips on how to check that?
The car will be converted to gas in due time but for now I need to squeeze every last bit out of petrol as I can. Any guidelines, hints, tips, tricks i can follow to sort this out?

[GTwizard]

Good thing. It is supposed to do that.

[TUFFTR]

Interesting, then I have a problem with my other car LOL it's always done that.
Well then, the hunt to why it's going through so much fuel remains.

[OBXBoost]

Replace the fuel filler cap?

[Mike-92RT]

When your car is low on gas, it should make that "Pshhh" sound. Try replacing your gas cap like OBXBoost suggested.

[DocWalt]

It's not supposed to "psshhhttt" Do you have a logger? Sounds like it's running pretty rich!

[jba3]

The pssshhhttt means your tank is getting pressurized. It shouldn't do it. Check the normal mileage stuff - tires, o2 sensors, etc

[TUFFTR]

Diamante is the one getting horrible consumption, replaced the fuel filter, air filte,r o2 sensor, timing belt, water pump, spark plugs, and next week going to drain the tank (this was the fuel filter....)



The magna has the 3.5L, gets near on 450km's a tank, but makes the pssssshhhhttttt sound when i go to fill up (empty of course) Is this something to do with the "charcoal canister"?
Tyres on both cars are checked fortnightly, Diamante is on 205/65/R15's @ 40psi and TR is on 235/35R19's @40psi aswell

Sorta stumped as to why one makes the sound, and the other one does not.
But, like you said, I'll go grab a fuel cap today!

[DocWalt]

That filter is pretty repulsive, haha.

The sound is because the EVAP system isn't venting the tank correctly. Did you retain the EVAP system, or cap it off when you did the swap?

[TUFFTR]

That filter is pretty repulsive, haha.

The sound is because the EVAP system isn't venting the tank correctly. Did you retain the EVAP system, or cap it off when you did the swap?

Now that you jog my memory I'm sure theres a piece of tape over one of the ends. I'll look up a diagram and find out what's supposed to go where.

And yeah, that fuel filter was HORRIFIC. Tanks gonna get drained next week with another new filter, and some cleaner injectors.