Problems starting. Ideas?

[Roseandpeter]

We have a hymer on a 2.3 Fiat ducato 2015 .
Back in may 2024, we broke down in holland. For a few years now the van needed more than one go to start, but this time it kept turning over and wouldn't start at all. No fuel getting through.The break down chap tried everything , but then phoned a Fiat garage who told him to give the fuel tank a few whacks. It worked. We took it to a garage, who replaced the low pressure fuel pump inside the diesel tank.. This involved a lot of labour. After a hefty bill we were off and no more problems......for awhile a least.

The van started first go for quite a while, but now needs more than one go again. Heart in mouth everytime. We were on an aire south france and she wouldn't start at all again. Last resort , tried hitting the fuel tank and she started! Been OK ish but it's making me wander for how long.
Both times the fuel level was just over half a tank, Maybe a coincidence but keeping her topped up in case it has a bearing. Also put posh diesel in to see if that helps.
Apart from thinking that the garage in holland only cleaned up the old pump and put it back in, despite charging for a new one, I'm stumped.
Any theories as to what could be happening, if it's not the low pressure diesel pump. If not, then why would hitting the tank help start it.
Thanks in advance

 

[funflair]

Sorry I don't have answers for you Rose and Peter but it keeps on working till you can get home at the very least, if it is/was the low pressure pump it would be a strange coincidence if a new one was also playing up as well

 

[Pausim]

Next time it won’t start try removing the fuel filler cap and listen for an intake of air as you do it. One car I had trouble starting had a blocked breather and removing the cap relieved the pressure drop.

 

[PP Bear]

From a past experience, I had a truck that would play up in very much the same way. Somehow I managed to get some leafs in the tank and they would suck against the pickup pipe, until I gave it a whack and dislodged them, then stated ok.

Could it be that you’ve got debris, dirt, muck or whatever in the tank and it’s getting stuck on the pickup pipe and the whacking gets it shifted.

 

[chesterfield hooligan]

The only trouble with debris in the tank, you would break down whilst driving ie cutting out when motoring not particularly when starting.

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[Carpmart]

Above post from PP Bear seems like a very plausible scenario! Giving the tank a whack can only be dislodging some debris on the pick up, it can’t really be anything else.

You’d like to think that the garage that replaced the ‘broken’ lift pump bench tested it to check that they had found the problem. No of course they didn’t.

 

[Carpmart]

The only trouble with debris in the tank, you would break down whilst driving ie cutting out when motoring not particularly when starting.

I hear what you’re saying, but I think with the fuel sloshing around it’ll keep itself clearer the majority of the time.

 

[yorkiebar]

Next time it won’t start try removing the fuel filler cap and listen for an intake of air as you do it. One car I had trouble starting had a blocked breather and removing the cap relieved the pressure drop.

On our 2023 Ducato, when I open the fuel filler cap then there is a noticable pressure equalisation noise (air intake I guess). I thought that this was odd, could indicate an issue ?

 

[Googlebot]

Make sure the immobiliser symbol turns off. Mine did this and I thought it was the fuel pump.

Turns out it was the antennae ring in the ignition barrel for the immobiliser.

 

[PP Bear]

The only trouble with debris in the tank, you would break down whilst driving ie cutting out when motoring not particularly when starting.

Not in my case, for whatever reason it would only happen when I went to start it. Could be that as diesel is a recirculating system, that the return flow is sufficient to keep the muck moving, where as when it’s stopped and if there is any muck in there, it settles down and then only gets sucked up on initial startup.

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[Guigsy]

On our 2023 Ducato, when I open the fuel filler cap then there is a noticable pressure equalisation noise (air intake I guess). I thought that this was odd, could indicate an issue ?

No, it's supposed to do that. It creates a negative pressure to keep fuel vapours from leaking out. Evap system can fail in various ways, but you'll get a check engine light if it does.

 

[yorkiebar]

No, it's supposed to do that. It creates a negative pressure to keep fuel vapours from leaking out. Evap system can fail in various ways, but you'll get a check engine light if it does.

Yes, did some googling and checked the Ducato manual (duh!)

"The sealing may cause a slight pressure increase in the tank. A little breathing off, while slackening the cap is absolutely normal."

So it's a +ve pressure relief from the tank, not an air intake according to Fiat.

 

[L' Hobo]

We have a hymer on a 2.3 Fiat ducato 2015 .
Back in may 2024, we broke down in holland. For a few years now the van needed more than one go to start, but this time it kept turning over and wouldn't start at all. No fuel getting through.The break down chap tried everything , but then phoned a Fiat garage who told him to give the fuel tank a few whacks. It worked. We took it to a garage, who replaced the low pressure fuel pump inside the diesel tank.. This involved a lot of labour. After a hefty bill we were off and no more problems......for awhile a least.

The van started first go for quite a while, but now needs more than one go again. Heart in mouth everytime. We were on an aire south france and she wouldn't start at all again. Last resort , tried hitting the fuel tank and she started! Been OK ish but it's making me wander for how long.
Both times the fuel level was just over half a tank, Maybe a coincidence but keeping her topped up in case it has a bearing. Also put posh diesel in to see if that helps.
Apart from thinking that the garage in holland only cleaned up the old pump and put it back in, despite charging for a new one, I'm stumped.
Any theories as to what could be happening, if it's not the low pressure diesel pump. If not, then why would hitting the tank help start it.
Thanks in advance

If bashing the tank helps, I would check the electric connections on top of the pump because, if the is a poor connection, probably the vibrations are connecting it again.
I presume the filter has been changed but cannot see how bashing the tank could affect that BUT there are a couple of plugs going to it. (I don't know what they are for) but I would give them a quick spray with contact cleaner.

Seems strange that it's only on start up, it has to be something electrical, what does a scan throw up?

It couldn't be that the fuel cut off in the passenger footwell has been accidentally kicked, could it?

 

[Guigsy]

Bashing the tank to make it go is normally a sign the in-tank pump is on its way out. I'd guess it's going again. Could be bad luck. But it might be caused by an underlying issue. Do you hear the fuel pump spin up when you put the key in and turn it to the running position (not starter)?

 

[Roseandpeter]

It's not the immobiliser or the cut off. Tried that thanks. I think we'd be very unlucky for a second pump to go, so leaning towards either the pump wasn't replaced or an underlying issue such as debris. Never heard the fuel pump spin , but not been listening for it....its a puzzle.

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[L' Hobo]

It's not the immobiliser or the cut off. Tried that thanks. I think we'd be very unlucky for a second pump to go, so leaning towards either the pump wasn't replaced or an underlying issue such as debris. Never heard the fuel pump spin , but not been listening for it....its a puzzle.

I think if it was debris, I would have thought it would have interfered with performance, not just starting?

When was the fuel filter last changed and did it show evidence of crud or water?

 

[GeoffnDee]

As L' Hobo has suggested it would be worth checking the multi-plug on the top of the pump as 2 of the pins in it are for the power supply and ground connection for the pump , the other 2 pins are for fuel level readings/ground