Technical FUEL FLOODING

[cammo1970]

We have been without the car since 20th January at first with my local mechanic and then a European specialist.

The car is flooding. When they can get it running if they leave it overnight it floods again

I have now been advised they are at a time now that parts will need to be replaced on a trial and error basis. I was hoping to avoid this scenario and hence I have reached out ON THIS FORUM

please refer to the attached the checklist of works carried out thus far

The car has done 46 300 kms

 

[the green vanper]

Hello,

Is the car the 3 door FIAT 500, or the 5 door FIAT 500L?

What is the engine?

 

[cammo1970]

it is a 3 door Fiat 500

 

[Mike1alike]

It's very weird that they've just jumped to replacing ECU, although they had no proof that ECU has a fault.
I think the problem you have is caused by something that's listed in that invoice. Fuel pressure: 4 bar constant. Do a thorough check-up, knowing the specific details of your engine, but I think the fuel pressure on yours should be 3.5 bar. Over pressure can cause flooding and probably the fuel pressure regulator is faulty.

 

[varesecrazy]

it is a 3 door Fiat 500

1242cc?

 

[varesecrazy]

It's very weird that they've just jumped to replacing ECU, although they had no proof that ECU has a fault.
I think the problem you have is caused by something that's listed in that invoice. Fuel pressure: 4 bar constant. Do a thorough check-up, knowing the specific details of your engine, but I think the fuel pressure on yours should be 3.5 bar. Over pressure can cause flooding and probably the fuel pressure regulator is faulty.

Sounds plausible..
But how is it flooding 'overnight'..?


Sounds like some electrical problem

Pump left powered, so tank fuel keeps flowing to the rail..?

 

[348azeus]

Fuel pressure is a bit high but that should only affect the car running. It sounds more like a problem with one or more injectors probably always open they may flow correctly but might leak overnight. Cheapest option would be to try used fuel rail with injectors.

 

[Mike1alike]

But how is it flooding 'overnight'..?

Fuel it's already in the rail since the engine was running. The pressure regulator doesn't 'open up' to normalize the pressure and it stays the same after engine is turned off. The fuel line, including the rail, remains under pressure. And that pressure makes the fuel sip through the injectors. Maybe there's carbon deposits on the injectors that make them not closing perfectly. Anyway, the 4 bar caught my attention. I would first start checking if that is normal pressure or not. If I'm wrong, my bad!

 

[varesecrazy]

Concensus appears to be
Change injectors - to rule them out

Not sure of used availability near you.. ,

But should still be cost-effective

 

[Mike1alike]

Change injectors - to rule them out

I don't recommend! Firstly, they are not cheap at all. And the ones on the car I'm kind of 99% sure that they're working. Might just need to be cleaned.
My recommendation: sort out what is the normal fuel pressure for that engine, if it's not 4 bar fix what's causing it (probably the regulator). Then, take down the injectors to see how they look and how they work. Having them on the rail, using a tester connected to the car, you can see them in work. Firstly, starting the fuel pump, see if there's any sipping from any of them and using the diagnose interface you can select each one of them to open and see how they spray and if is any sipping afterwards. If they need cleaning, you can either put them back and use a fuel additive injector cleaner (I used STP and was satisfied with it) or you can take them out of the rail and clean them putting carb cleaner under pressure inside them and intermittently connecting them to 12 V, using this kind of a system:

 

[cammo1970]

Thanks everyone for their responses, we have already tried all of your suggestions and appreciate you taking the time to assist.

 

[varesecrazy]

Thanks everyone for their responses, we have already tried all of your suggestions and appreciate you taking the time to assist.

So you've swapped injectors, and fuel regulator..

Has the Battery power been disconnected overnight? Ruling out prospect of pump running independently..

And it still "floods"..

 

[Mike1alike]

we have already tried all of your suggestions

So, what is the normal pressure for the fuel pump on your model?

 

[cammo1970]

So, what is the normal pressure for the fuel pump on your model?

4 bar

 

[cammo1970]

So you've swapped injectors, and fuel regulator..

Has the Battery power been disconnected overnight? Ruling out prospect of pump running independently..

And it still "floods"..

yes twice

 

[Mike1alike]

yes twice

Do you mean there that you've disconnected battery or also that you put new injectors/fuel regulator?
What you can do is to take the injectors out of the intake manifold (connected on the rail), activate them using MultiEcuScan to see how they work then let them for a while and watch what's happening. Even better, video record it to see when and how is the petrol coming out. The injectors are the only possible path for the petrol to get to the combustion chambers so you gotta figure out how does it do it after you turn the engine off. And it's really strange cause all of them leak petrol, so I don't think that all of them got damaged in exactly the same way at once. But something is happening there.

 

[Mike1alike]

When you disconnected the battery the engine still got flooded?

 

[varesecrazy]

yes twice

Can you please try and quantify how much fuel is involved here

Enough to run poorly,

Or a bigger quantity to create actual pooling of fuel

I don't think the fuel rail will hold more than 300ml?