Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem | Technical matters | Back Room Forum

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Mon 18 Feb 2019 09:14

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

Good Morning, I am hoping someone can steer me in the right direction, my wife has a very clean year 2000 Ford Fiesta, recently after a no sytart scenario a mechanic diagnosed a faulty fuel pump. A new pump was fitted via a hole that was cut under the n/side rear side pan. The car now starts and runs fine but now the fuel gauge indicated zero ( it has half a tank ) I know the new pump had a combined fuel float device. When I take the reaar seat out and give the 5 pin ford connecter a wriggle the fuel gauge comes to life again, but not for long. I am guessing one of the thinner wires that sends a signal to the fuel gauge has a fracture or break due to vibration/age.

The car is not worth a lot but my wife wants to keep it as long as possible, can anyone suggest a possible remedy to overcome the fault I have described ?

thank you,

Edited by KenC on 18/02/2019 at 09:18

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Mon 18 Feb 2019 11:07

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - elekie&a/c doctor

Yes, seen this many times before . You have the wrong pump/sender unit fitted. There are several variations of this part ,and they all look similar , but work differently.

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Mon 18 Feb 2019 12:20

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

thank you for reply, I have the box the new pump came in and have checked the part number on the manufacturers website, according to their information it is the right pump for my cars build date.Do you have any idea why if I squeeze the wires at the 5 pin connector the gauge will work again ?

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Mon 18 Feb 2019 13:53

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - elekie&a/c doctor

Is there any evidence of corrosion or overheating on any of the pins? Is this a genuine Ford part or after market variety? How much was it?

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Mon 18 Feb 2019 15:48

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

The local mobile mechanic sourced the pump from the towns Auto factors, it is a Carbiare brand cost of pump was £118, the mechanic did not report any signs of overheating or corrosion on the plug pins, the old pump pins were in fairly clean condition for a 18 year old car..

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Mon 18 Feb 2019 17:44

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - bathtub tom

At that price I'd have been tempted to fit an inline electric pump.

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Mon 18 Feb 2019 20:02

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - elekie&a/c doctor

If the connectors to the pump module are in good order, then I would think it unlikely the wiring is in trouble. I presume the original fault was the pump failed and the level sensor was ok. The make fitted will be Cambiare . Not the best quality but there are plenty worse. Squeezing the connector may be moving something inside the tank module. Unfortunately the genuine part from Ford is over £300 , possibly more than the value of the car. Do you still have the old part ?

Edited by elekie&a/c doctor on 18/02/2019 at 20:03

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Mon 18 Feb 2019 21:22

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - sammy1

If you cannot find the fault, determine the sensible MPG that the car does and fill the tank based on a conservative usage. Brim the tank every time based on miles covered and carry a can of fuel

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Tue 19 Feb 2019 15:37

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

Hello yes I still have the old pump, the original symptoms were fuel level gauge ok, no sound from pump pressurising & not starting.

The car has been used daily for a week since new fuel pump installed, sadly today car broke down again with the very same symptoms, no fuel pump pressurising and no start.

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Tue 19 Feb 2019 17:06

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - elekie&a/c doctor

Is there any fuel in the tank ? I bet the fuel gauge is reading wrong.

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Tue 19 Feb 2019 18:12

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

Yes there is fuel, approx 13 litres were added after the new pump was fitted, initially the fuel gauge did function ( with the new pump) and it registered just over half a tank, only 15 miles have been travelled, This afternoon I went back with a friend and a tow rope to recover the car. After one no start I sqeezed the fuel pump 5 pin terminal and it started, I drove it home without any issues. I will speak to the mechanic later to see if he has any ideas..

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Wed 20 Feb 2019 10:01

Ford Fiesta Mk4 facelift 1.25LX year 2000 - Intermittent electrical wire problem - KenC

To add further ingredients to the symptoms, this morning the car started as normal but no fuel gauge reading ( empty tank light on) after checking with my owners handbook I checked inside the central fusebox and noticed there were 5 small identical relays, one of which was for the fuel pump. I removed the fuel pump relay ( number four on the diagram ), as an after thought I turned on the ignition without the fuel relay in place to check there was no fuel pump sound ( there was none ) then noticed that without the relay in place the fuel gauge came to life and indicated a half tank of fuel.

I have marked each relay with a paint spot and swapped the cooling fan relay with the fuel pump relay, the car started and the fuel gauge worked ( half a tank)

After swapping the relays as above the car still started and the fuel gauge functioned, I tried several starts in the driveway, after the 5th or 6th start the fuel gauge stopped working again but the car still started.

If you recognize these symptoms or have any suggestions please let me know.

Edited by KenC on 20/02/2019 at 10:50

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