the previous owner of my car did all the usual 'must-have' mods as seen on fb & forums - hence the charcoal canister delete (& mk2 dash swap (returned back to mk1) / ac removal & (ANNOYINGLY) also removed the PAS ) and I wonder what has been done - I'm slowly undoing these and other 'upgrades' and the car now works
anyway, as I say, the fuel tank pressurises after a drive, when opening the cap ist releasing a puff of fuel vapour and I wonder if anyones suffered with this or is it a Mazda design quirk?
my Eunos has always had a pressurised fuel tank, I'm guessing theres a blocked or sticky vent-valve somewhere, possibly connected to the vent pipework that used to feed the canister thats been deleted?
I appreciate that the cap has a vent-valve or pressure-relief valve and thats something on my list to inspect (one day hopefully, I've been thinking about this for a year... )
Hi Zed, I would say its normal to get a pressurisation of the Mx 5 Tank, It has happened on the last three cars of mine. It happens with or without the charcoal canister. Exhaust heat and the heat from the fuel pump will all add up to vapour expansion. I think there is a relief valve above the tank under the deck cover.
...then this 'check-valve' - what's it 'check'?...
Check-valve is just another term for a one-way/non-return valve. More common use in American English.
"Check" in its meaning of "stop" rather than "make sure".
Anyway, I really just dropped in to say both my Mk.1's have exhibited the "pshhht" of slight pressure in the fuel tank when opened, unless the car was still cold. The main reason the pressure builds up (I assume) is because the fuel is heated as it's constantly pumped to the (hot) fuel rail and the excess returned to the tank.
I wonder if later Mk2.5s with returnless fuel systems don't do this.
from what I know, there is a certain amount of 'normal' gas pressure that the tank will have if there is fuel in there, the check valve is more than a one-way valve, it'll vent if there is *too much* but it won't vent if the pressure is within normal limits i.e. a few psi. that's the psssht we get when we open the tank up to fill it. if you don't get a psssht + you have a gassy smell when cold then the check valve may have failed open.
with the power of spares & hoarding, I've investigated one of these 'check-valve' thinggies (& the 'roll-over' valve)
so, bolted to the top of the tank theres a 'roll-over' valve as a safety item in case of the 'driver' having an issue & running out of tallent or being the first to arrive at the scene of the accident - obviusly this refers to tipping the car then attached with a short length of pipe is said 'check-valve'...
its an aluminium-ish construction that looks to be non-serviceable so if it's Jeffed then bin & replace, testing was done scientifically (blow through both ends to see what happens ) and this shows it's normally 'closed' and opens with pressure or vacuum.
maybe later I'll strip the back of my car & 'test' the one on it
wannabe: What's the punishment for a lapsed MOT nowadays? Diary commitments and the need to still put it back together suggest missing my MOT date but needing it before I can get one sorted...
Jul 2, 2019 21:41:31 GMT
Zed.: used to be a ~£30 fine BUT I believe its income related....... (or it was 9 years ago when I got done )
Jul 2, 2019 23:46:11 GMT
Crumpets: "Standard cost" is £54.85 - (That's the highest VOSA will allow a garage to charge for a standard car test) most garages usually do it for £30-£50 to be competitive.
Jul 3, 2019 7:05:46 GMT
JamesMk3: Issue with no MOT these days is as soon as the test elapses, insurance won't cover you. If the old bill catch you, it's 6 points and £300 FPN, or court, which can be anything up to a ban and unlimited fine.
Jul 3, 2019 15:58:45 GMT
wannabe: Is that actually true?? What happens if you're driving to an MOT without a current MOT, which the law permits you to do?
Jul 3, 2019 21:28:13 GMT
Crumpets: You’re only allowed to drive your car when its MOT has expired if you’ve booked an MOT and are driving to the test centre. If you’re stopped by the police on the way, you’ll have to be able to prove that you have an appointment.
Jul 4, 2019 7:51:01 GMT
Crumpets: If your car fails its MOT, you can only drive it if the previous year’s MOT is still valid (i.e. the test took place on a date earlier than last year’s). If your vehicle is deemed ‘un-roadworthy’ the above doesn’t apply and you can’t drive it on the
Jul 4, 2019 7:51:58 GMT
Crumpets: By 'Un-roadyworthy' - I mean if it has failed its MOT on a "Dangerous" defect as per the changes applied on the 20th May 2018. Sorry to spam the chat, just a little difficult to explain in 256 letters haha.
Jul 4, 2019 7:55:23 GMT
wannabe: Info is always welcome I thought that a Fail is a Fail is a Fail now - so you lose the ability to drive on the previous MOT in all circumstances?? It also is not clear if your insurance is invalid without an MOT?? I thought it was valid!
Jul 4, 2019 10:17:58 GMT
FFS Corders: Ask your insurer about that, they will be able to give a definite answer over if they'd pay out or not. The fact you need insurance to take it to an MOT and not tax should be a good indicator
Jul 4, 2019 12:39:38 GMT
Crumpets: Alarm keeps going off in the night - Getting annoying now & I wasn't popular at 4.30AM. Gurrrrr
Jul 6, 2019 7:52:12 GMT
wannabe: This is why I think alarms are a bit of a waste of time nowadays - everyone ignores them, gets annoyed by them, and thieves will take the car if they want it anyway... lol May I suggest a steering wheel lock?
Jul 6, 2019 11:49:04 GMT
Zed.: ~20 + years ago, I used to remove the battery, gearstick & steering wheel from my 2L ford engined Chevette (was living in a dodgy area of Swansea)
Jul 6, 2019 15:27:16 GMT
FFS Corders: Gearstick is a new one for me lol
Jul 6, 2019 16:10:20 GMT
Crumpets: Battery is good, I've jkust installed a battery isolator to stop it, only does it once ever so often - Might remove it down the line and keep it for the central locking aspect.
Jul 7, 2019 13:27:22 GMT
FFS Corders: Yaay MOT passed. Now got a few niggles to fix soonish
Jul 9, 2019 16:11:17 GMT
Zed.: niggles? is that a word for friendly advisories? always a feel-good moment when you have that pass paper in your hand, 12 months to worry about fixin the next problems
Jul 9, 2019 20:44:03 GMT
FFS Corders: Only one of those was tempermental hazards. The others are genuine niggles such as a couple of tired hoses and calipers that are on the way out. Getting a proper MOT means I find out what to prioritise
Jul 9, 2019 20:52:53 GMT