NB MX5.

Bit of an oversight on the engineers part. The fuel cap is on the boot.

Last year in March we had torrential rain which flooded the fuel hose thanks to a blocked drainage pipe.
Car ended up at the garage, old fuel pumped out and things opened up to allow to dry.

Fast forward to now….

Again, last weekend massive rain.
Go to take the car to the MOT, give it a 20 minute blast along the motorway to give it a bit of a workout. 200m from the test centre and it starts pogoing, like it’s filled with kangaroo petrol.

Called the tow people, they’re on their way.

I opened the fuel lid and have left it open. Been sat there for half an hour and it now starts up…. Can’t have been masses of water in there, right? I mean, the drain was cleared.

Should I risk it or take it to a garage?

Brim it with fuel just to dilute the water content?

They don’t mix, though. The fuel will sit on the water (and the pick up is at the bottom). That said, if it is running OK I’d probably chance it

Yup…. Made it now to a petrol station, brimmed it full. … Pulled away from the petrol station and 200m it died

Have managed to get it to the side of the road…. Got it started again. Ram it for 5 mins at half throttle.

Thought it might help heart the engine and burn off the moisture.

It died again.

Set light to the petrol, it’ll burn the water off

*INAM

^^
In seriously **** tempted…! It’s fully comp, I think… The payout is probably more than what I’ll get when I sell it… 😁

Old solution was to chuck a bottle of meths in BUT as you’ve already had the fuel drained there shouldn’t be any water.

Did you change the fuel filter? Were the pump and injectors bled of the bad fuel?

I’d be taking a sample after the fuel pump, putting it in a jam jar and seeing if there’s any water layer. If so, discard that tank full.

In any case bleed everything after the fuel pump. And check the underwing drains before every flight.

So it’s wet.

It’ll idle but won’t rev

I’ll take ht leads for blockbuster bob.

You seem to have decided what the issue is without looking objectively at what’s occuring. I’m not saying it’s the HT leads catagorically but I’m moving you away from the fuel tank because if it was an issue like your experiancing – especially after the work you say was done there would be outrage from every mx5 owner ever every time it rained.

Trailrat
The mazda b6 lump is notorious for watet gilled spark plug wells and wet HT leads
This sounds like a combination of wet ht and dodgy fuel
Let it sit, remove fuel tank outlet and divery towards jam jar
Check for water
No water, crack on
Watr means dump a frw ltrs then retry
No water means wet ht so abuse the whole thing with wd40 and cf roll

Trailrat
The mazda b6 lump is notorious for water filled spark plug wells and wet HT leads
This sounds like a combination of wet ht and dodgy fuel
Let it sit, remove fuel tank outlet and divery towards jam jar
Check for water
No water, crack on
Watr means dump a frw ltrs then retry
No water means wet ht so abuse the whole thing with wd40 and cf roll

Isn’t it fairly easy to drain a fuel tank. I have never done it but it must be via an accessible drain. And the fuel filter is also fairly routine service issue.

Trailrat
The mazda b6 lump is notorious for water filled spark plug wells and wet HT leads

I didn’t know that but without knowing it’s a Mazda I’d have looked at her leads before the fuel based on his symptoms.

Isn’t it fairly easy to drain a fuel tank.

Yes it is. It’s also possible it will create a build up of static while doing it which is not a good thing. Petrol tankers are earthed while delivering to forecourts.

Based upon cleaning out moisture build up from home heating oil tanks. Oils sit on top of water, fuel feeds from bottom of tank, so easily gets sucked in.
Good length of hose down filler to reach bottom of tank, pump/siphon out 10l (from memory ours had a 40l tank) and see what you have.

Good length of hose down filler to reach

Will have an anti-syphon mesh at bottom of filler surely . Most things from this century do.

Is there an in-tank, sock-like filter before the fuel pump?

Corrosion caused by previous water-in-tank episode may have caused flakes/particles of rust to develop and accumulate. It may be a gradual process but has now got to the stage that these flakes/particles are causing the engine to fuel starve and stop, due to the pre-pump filter becoming clad in these flakes/particles when drawing fuel. When the engine dies the pump stops and the particles drop again, meaning that the pump can function once more. The process then repeats.

Think I saw this on an episode of ‘The Skid Factory’, with a tank that had supposedly been cleaned. A replacement tank was the answer.

I’m chuckling because I had exactly this… On an NB…
Mine was caused by ‘borrowing’the filler cap for another car, and replacing with a jam jar lid as a very short term solution. Then forgetting.

Lots of head scratching before we figured it out.

Anyways, I pulled the hose off the fuel filter outlet, and stuck a length of fuel hose from there to a bucket. I jumped the pump, and pumped it all through.

I can’t remember if I jumped the pump at the inspection hatch with a 12v feed, or if I did it another way I’m afraid. I know on my other 90s Mazda I can jump two pins in the diagnosis box under the bonnet to run the pump, but can’t remember if the Eunos had the same.

Regardless, it was absolutely fine afterwards, no need to bleed the injectors or fit a new filter. Those lumps are tough as old boots.