Failed/Lumpy Start on Refuelling - Mk5 Ford Mondeo

[Emilyetal]

Hey folks. First timer here so be kind (apologies if this is posted in the wrong place).

I own a 2018 Ford Mondeo 1.5 Petrol EcoBoost (don't judge - my heavy right foot days have been temporarily left in my yooff to make room for more yooffs) with a rather peculiar problem.

At around 60k miles (now sitting at 70k) it presented with lumpy starting post refueling. It is a petrol engine, fully serviced and well looked after, and owned since a young 15k miles.

After refuelling, it will turn over but fails to start. On second try, the car will turn over and if I pump the throttle it will eventually start but remains lumpy. I practically need to heel-toe out of the forecourt and get the car going, and then all is right with the world again until the next refuel.

N.B. It doesn't matter if I refuel on a cold or hot engine, whether the tank is on empty or not, whether I put in a little, lot, or fill, or whether I use 95 or 99 RON. I have tried, I believe, every variation other than using my right pink toe to refuel.

I haven't changed the fuel filter or pump since owning, however because it is such an intermittent problem, I'm reluctant. Nonetheless, I haven't tossed the idea aside, but having just done a belt and waterpump change, I'm running on fumes myself.

Has anyone heard of this issue before. As most mechanics simply raise an eyebrow and send me on my way.

Open to sensible suggestions (I don't fancy looking like a p***k in a station any more than I already do).

Cheers, Emily

[Scrump]

That is a strange one.
Have you tried shutting off the car, opening the filler and then closing it before re starting the car? I.e. replicating refuelling but without adding any fuel.
Might help in narrowing down the problem.

As I read this post back to myself, what I have suggested sounds a bit daft, but no harm in trying.

P.s. welcome to PH.

[vw_99]

Vent on the fuel filler blocked creating a vacuum maybe so not letting fuel get pumped to the engine

[Emilyetal]

Scrump said:

That is a strange one.
Have you tried shutting off the car, opening the filler and then closing it before re starting the car? I.e. replicating refuelling but without adding any fuel.
Might help in narrowing down the problem.

As I read this post back to myself, what I have suggested sounds a bit daft, but no harm in trying.

P.s. welcome to PH.

Not a daft thought- someone did mention this to me before. Sadly I've given this a go. I did wonder if it was something to do with pressure from the Easy Fuel system.
Unfortunately it didn't make a blind bit of difference

Edited by Emilyetal on Saturday 22 February 12:05

[Emilyetal]

vw_99 said:

Vent on the fuel filler blocked creating a vacuum maybe so not letting fuel get pumped to the engine

Do you know would I go about unblocking it?

[ARHarh]

Emilyetal said:

vw_99 said:

Vent on the fuel filler blocked creating a vacuum maybe so not letting fuel get pumped to the engine

Do you know would I go about unblocking it?

Just leave the cap off, and try starting it.

[Emilyetal]

ARHarh said:

Emilyetal said:

vw_99 said:

Vent on the fuel filler blocked creating a vacuum maybe so not letting fuel get pumped to the engine

Do you know would I go about unblocking it?

Just leave the cap off, and try starting it.

It's an Easy Fuel port, so it's a capless system. Sorry if I'm being dense.

[E-bmw]

vw_99 said:

Vent on the fuel filler blocked creating a vacuum maybe so not letting fuel get pumped to the engine

If the vent was blocked, the vacuum would be pulled with the engine running, not when the cap is removed to fuel up the car.

[E-bmw]

Emilyetal said:

I haven't changed the fuel filter or pump since owning, however because it is such an intermittent problem, I'm reluctant. Nonetheless, I haven't tossed the idea aside,

But, going by what you say, the issue isn't intermittent.

An intermittent problem is random when it happens & random when it clears, your fault (going by what you say) is 100% regular every time you fuel up.

If it were my car, I would be changing the filter, checking all fuel lines especially around the pump/filter.

I assume the filter is an in-tank one.

While you are in the area & if it is not an in-tank one get the inspection cover off & check the inside of the tank for debris.

ETA.
Try the "second time" without pumping the accelerator pedal.

Also, next time try turning the car on without actually trying to start for a few seconds first.

Edited by E-bmw on Saturday 22 February 15:19

[LordLoveLength]

I’d be looking around the purge valve / charcoal filter - loose or broken pipe or a failed valve.
No check engine light? Does it do it if you go through the motions of refuelling but not actually putting fuel in?

[GreenV8S]

You mentioned the problem happens after refueling, and also happens if you pretend to refuel without actually adding fuel.

Does it also happen if you shut off the engine and restart it? Does it matter how long it was shut off for? Does it matter how hot it was before you shut it off?
Does the problem happen 100% of the time when you go through the scenario that causes it?

If you can find the minumum set of conditions that provokes it consistently then that will be a big help diagnosing it.

[Emilyetal]

Thanks all that have had an input.

I'm going to check these off this week (minus the replacement of filter/pump, only to take the conservative routes first) and I'll come back if I have any news.

I really do appreciate it. Wish me luck.

[Peanut Gallery]

Another vote here for what would have originally been leaving the filler cap off until you start the car, but as you say it is an easy-fuel system. This would then get me checking over the canister valves etc..

[ARHarh]

Peanut Gallery said:

Another vote here for what would have originally been leaving the filler cap off until you start the car, but as you say it is an easy-fuel system. This would then get me checking over the canister valves etc..

Don't these systems have a pipe in the boot to allow you to add additives to the fuel? My Volvo does. You could use that, or the filler pipe from any petrol can to simulate leaving the cap off.

[chris1roll]

Have you tried just leaving the engine running while filling up?