Electric Fuel Pump Question

[igotalake]

Hi, I am wondering if anyone can confirm something for me about an electric fuel pump, the inline type, which is fitted to some Fords. What I want to know is does it have a pressure switch built in so that it will pump until pressure gets to 3 bar or whatever then switch off automatically or is the switching controlled by the ECU and a pressure sensor elsewhere ?
Sorry, I know it's a bit vague and not about a specific model of vehicle but the descriptions of the pumps for sale don't really say whether they do this or not.

Thanks in advance.

[metalworker0]

You don't say what for -- as it could have a bearing on what sort of answer you get or if you get an answer at all !

I'll start off by saying ..that i think you have a 2.4 TDDI

all the best.mark

[igotalake]

It's actually for a Mitsubishi !

The thing is I have fitted these pumps before on Fords and I just want to assure myself what model of Transit to buy for if anyone knows a pump that does switch automatically ?

[knobby1]

It's actually for a Mitsubishi !

The thing is I have fitted these pumps before on Fords and I just want to assure myself what model of Transit to buy for if anyone knows a pump that does switch automatically ?

If it's for a TDDi, you're probably wasting your time & money.

The high pressure fuel pumps on the TDDi's aren't expecting to be supplied with any type of fuel pressure, their inlet side is a suction type pump and the low pressure side of the fuel system runs at a slight vacuum as the pump draws fuel up from the tank..

If you have air ingress which requires you to fit a supply pump....best you sort the issue properly instead of working around it.

Lord Knobrot

[igotalake]

Do you know if the lift pump on a tddi is controlled by its own internal pressure switch ?

[knobby1]

Do you know if the lift pump on a tddi is controlled by its own internal pressure switch ?

No, It's not a lift pump in the normal sense.

Lord Knobrot

[igotalake]

On my 2.4 TDE/TDDI there's a pump in the filter housing and I know there's an electric pump on a Mondeo TDDI which is underneath between tank and injection pump but I don't actually know if either is self-operated via internal pressure switch or by the ECU...That's my problem.

[knobby1]

On my 2.4 TDE/TDDI there's a pump in the filter housing and I know there's an electric pump on a Mondeo TDDI which is underneath between tank and injection pump but I don't actually know if either is self-operated via internal pressure switch or by the ECU...That's my problem.

Some of the early TDDi's, 120/125's had a pump on top of the filter housing....Was discontinued on the later models as it wasn't really needed.

https://www.catcar.info/ford/?lang=en&l ... NzkyKzA%3D

Lord Knobrot

[Frag]

The fuel injection pump itself is different on the 120/125 without the electric lift pump,they are not interchangeable.
If you’ve seen the price of the filter housing with the electric pump,there are other better options unless using it on the vehicle it’s intended for.

The earlier tddi’s with electric lift pumps,a.f.a.i.k. Run for 30 seconds with ignition on but engine off,then constantly once engine is running,they are PCM switched via a relay and not pressure switched.
They also usually have an inertia switch fitted to cut them off in case of an accident.

[igotalake]

Right, so they are PCM controlled. That's the info I was looking for.

Many thanks,

Don't suppose you can point me in the direction of one which does switch automatically with pressure ?

[Frag]

Nothing Ford that I know of,prior to the newer 2litre / panther eco blue vehicles,have pressure controlled low fuel pressure pumps,and those are the in tank sender unit type anyway.

I’d be looking at aftermarket facet type or SU replacement fuel pumps,just search 12v fuel pump on your preferred retailer.

I don’t think a pump that runs constantly,with engine run or ignition will hurt anything,if it’s low pressure.
As mentioned previously this is how earlier fords work,PCM runs the pump,but do not control or switch it via pressure,they don’t even measure the low side fuel pressure….

[igotalake]

On the switching there's sod-all information via the online retailers though. I could go into an actual shop and hope to get an old guy who knows his stuff I suppose.

The old SU pumps from a mini let's say, they were pressure controlled ? Maybe that's the best option although they are a bit bulky.

[Frag]

Do you want to expand a bit more on the where and why ?
I know it’s a Mitsubishi,but what vehicle/model,did it have a manual or electric lift pump from the factory,and why do you think it needs one now if not ?

[igotalake]

It's an old Canter and the lift pump in the injection pump is apparently knackered and he has fitted a 12v pump that runs constantly but this causes problems for him, I said we can fit one that doesn't run all the time but it's proving to be a mission finding one that can be just wired in to a live ignition feed.

Thanks for all your input by the way.

[Frag]

There are loads of 12v fuel pumps available,only the SU copy / knock offs seem to mention pressure regulating.
I’m guessing the facet type ones will also,
The only other option would be to use any pump,and fit an inline fuel pressure regulator.
Wire the pump to run constant on ignition / engine run.