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Td5 fuel pump - failure symptoms


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We have a 2003 Defender 90 Td5 in Africa.

The driver suspects the fuel pump has failed. These are the symptoms:

1 - "Check engine" warning light on dashboard;

2 - Vehicle will only idle, dies if you apply some revs;

3 - The fuel filter is very hot to the touch (but has been replaced as a first step);

4 - Oh, and the fuel pump's been making some funny noises for a while...

The driver (competent mechanic, but little direct LR experience) is currently sat reading the Workshop Manual's Fuel System section!

Does anybody think that it is not the fuel pump before we send one out?

Any advice gratefully received.

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fuel filter being hot is characteristic of the the td5 engine

does it die to stall or die to tickover with revs?

fuel pumps do whine a fair bit and can be a sign they are on their way out.

Has the vehicle been run dry at any point - or run with low fuel level that leads to the pump overheating and then failing.

i did think that if the pump was knackered it didn't run at all.

Does he get a HP feed at the fuel pump regulator? fuel filter side of engine.

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Noisy fuel pumps which suddenly aren't noisy any more are usually dead ones. However it doesn't usually trigger a check engine light if my memory is correct. Check engine lights/no throttle have been known to be dodgy ECU's.

The best thing to do is plumb in a pressure gauge to the RH rear corner of the engine, where the fuel temperature sensor is located (take out the temp sensor and screw in an appropriate adaptor). This should read 58psi with the ignition on, if it doesn't then the pump is probably knackered. If the pump is producing the right pressure, then I'd try a new ECU next, but you need a computer to program the security code and injector grades which could be a problem in the middle of Africa...

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Jungle Update:

It runs fine for about a mile when started. Then if at speed starts to fail when you apply throttle but letting off throttle brings the engine back to life. When at low speed the check engine light comes on and the throttle will not work. It doesn't die just sits happily at idle. Turning off the ignition resets it and will be ok till we get to maybe half throttle then light on and no throttle again. It has never been run dry but fuel is notoriously dirty out here.

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Jungle Update:

It runs fine for about a mile when started. Then if at speed starts to fail when you apply throttle but letting off throttle brings the engine back to life. When at low speed the check engine light comes on and the throttle will not work. It doesn't die just sits happily at idle. Turning off the ignition resets it and will be ok till we get to maybe half throttle then light on and no throttle again. It has never been run dry but fuel is notoriously dirty out here.

Could be a dodgy throttle potentiometer!

Had them work fine on light throttle but go "out of range" at higher throttle and engine light comes on and into limp home.

Will re-set with ignition cycle only to fail again when throttle passes a certain point.

Mark.

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thrpttle potentiometer or pump. same thinking here. they are both common faults on the defenders. iirc there is a choice of 2 throttle potentiometers. a 2 track or 3 track (can`t be certain at the mo as my head hurts!) make sure you get the correct one. it will have to be fitted using t4 though. fuel pump is a right royal pain in the arse to do. probably the most common of faults on the defender. something a bit obvious but is there water in the tank perhaps?

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In dusty conditions the air filter will block and then get sucked into the intake allowing unfiltered air through. They don't last 20k kms so check them regularly.

I would check the fuel pressure as Steve says. Unfortunately a computer doesn't help as the ECU has no idea what the fuel pressure is. So you have to act like a real mechanic for a change.

If you are in the middle of Africa.... get a Tdi

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Thanks to everyone for their contributions.

The vehicle is going to get some workshop time this week, to see if the fault can be traced.

As it happens, won't be such a bad thing if it needs parts replacing - the driver's coming home for Christmas soon, so can take anything needed back with him. And it it doesn't work whilst he's away, nobody can "borrow" it, can they?!

Will let the forum know what it turns out to be.

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Thanks to everyone for their contributions.

The vehicle is going to get some workshop time this week, to see if the fault can be traced.

As it happens, won't be such a bad thing if it needs parts replacing - the driver's coming home for Christmas soon, so can take anything needed back with him. And it it doesn't work whilst he's away, nobody can "borrow" it, can they?!

Will let the forum know what it turns out to be.

The other thing that can cause similar faults is a faulty ECU ;)

(actually just noticed Mr BogMonster has pointed this out already)

If the ECU is at fault, when you plug the diagnostic kit in, you will usually see: Topside switch failed pre-injection

Ian

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