Fiesta Diesel Mk 4 - Fuel hoses

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Sun 28 Mar 2010 20:33
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

The fuel hoses that connect onto the Bosch fuel filter,are these are prone to fail? The connectors don't seemed to be gripping the pipes at all and I can easily slid the hoses off with a gentle pull. The car refused to start the other day and I wondered if I had air in the system through these poorly connecting hoses. Should I replace them?

Edited by pullgees on 28/03/2010 at 20:38

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Sun 28 Mar 2010 21:52
Fiesta Diesel Mk 4 - Fuel hoses - oilrag

Are these the connectors that you push in and then pull out? Sounds like those on my Fiat`s bosch set up and I suspect they seal by internal O rings that apply radial pressure and as such don`t have the friction of a rubber pipe sealing on a metal stub.

Also a Bosch pump should self prime - from the tank - giving positive pressure through the pipes - unlike some systems that suck fuel up from the engine driven pump - allowing a partial vacuum that can facilitate air ingress.

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Mon 29 Mar 2010 00:20
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

Yes they have two little lugs which are suppose to push in, but mine seem solid, there is no movement on these lugs. Anyway the hoses simply pull off with ease with out squeezing these lugs. And yes they have o rings.

The morning it would not start I upped the bonnet and checked these hoses were pushed fully on. One of them seemed to move on slightly more but just a touch. After phoning the breakdown service I tried it again and it started immediately as if nothing was wrong, the engine didn't even fade.

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Mon 29 Mar 2010 11:41
Fiesta Diesel Mk 4 - Fuel hoses - oilrag

When I change the element on my Bosch system, the filter self primes from empty and it just fires up. There is movement on my unions too - you can slide them back and forward a little, with almost zero pressure.

I would have thought that on this system that any air ingress would be pushed out in the few seconds the ignition is on - tank pump, pumping - while waiting for the glowplug light.

Does it struggle to start every time it`s been left? and if you wait while the tank pump stops humming - does it then start instantly?

Don`t know If that helps, Pulgees.

All the best

Edited by oilrag on 29/03/2010 at 11:42

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Mon 29 Mar 2010 17:42
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

I'm not aware of a tank pump on this car. This problem happens if the car is left standing over night. Once the engine has fired up it's alright for the rest of the day. Could air be getting slowly drawn into the system causing the fuel to run back to the tank syphoning the filter in the process?

The sympton is that first thing in the morning it won't start during a 10 second crank on the starter motor. I leave it for 5 mins try again and it starts more or less straight away (given the fact that the engine is cold). I'm also giving it two goes on the heater plugs before starting.

Tomorrow morning I'm going to take the "in" hose off the filter and suck on it and see if I get a mouthful of fuel straight away. Yerk!

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Tue 30 Mar 2010 15:34
Fiesta Diesel Mk 4 - Fuel hoses - oilrag

Worth checking the glow plugs i would have thought. If only to exclude them.

I seem to remember that can be done measuring the current draw with a suitable ammeter - without needing to take them out.

Where are the Techs?

Edited by oilrag on 30/03/2010 at 15:38

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Tue 30 Mar 2010 16:34
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

It's definitely drawing air into the system. So I've renewed the filter yet again in case the other one had a minute leak and will see what happens tomorrow morning. Maybe I did the clamp up to tight causing a tiny split, they are only made of aluminium, we'll see.

A bush style method of checking for a dud glow plug is to disconnect the wiring that links them all up. Then attach a wire to the positive terminal and touch the top of each plug with the wire. The one that doesn't spark on contact is the dud one.

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Tue 30 Mar 2010 20:06
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

One other thought. The injection pump must be draining as well otherwise the engine would run initially until the fuel in the pump was used up. I would have thought the shut off valve would have prevented drain back.

Edited by pullgees on 30/03/2010 at 20:08

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Fri 2 Apr 2010 19:11
Fiesta Diesel Mk 4 - Fuel hoses - pullgees

Problem solved. If anyones interested there was a leak in the hose that connects up the fuel heater to the filter. The hose and the heater come as one piece @ £57. That is silly. So just got a bit hose and discarded the faulty one keeping the same heater and used old fashioned jubilee clips; I don't trust those Ford connectors.

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