corsa cdti - could someone please explain about fuel pumps

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Tue 8 Nov 2011 20:43
corsa cdti - could someone please explain about fuel pumps - cdti

could some one please describe to me what symptoms would occur with a faulty/failing low pressure fuel pump and the same for a high pressure fuel pump on a cdti engine.

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Tue 8 Nov 2011 21:05
corsa cdti - could someone please explain about fuel pumps - Peter.N.

Because of the proliferation of sensors on modern diesels if the fuel pressure was far out it wouldn't run, if it was marginal I would imagine it could be difficult to start.

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Tue 8 Nov 2011 21:21
corsa cdti - could someone please explain about fuel pumps - injection doc

Low pressure pump is the pre pump from tank to HP pump. When these fail its almost impossible to start or if it runs may cause loss of power as the HP pump can be starved of fuel and arated causing excesive wear

HP pump problems will normally cause a sensor to trigger and the MIL lamp to come on. If the HP pump has really lost it it may not start.

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Tue 8 Nov 2011 21:28
corsa cdti - could someone please explain about fuel pumps - cdti

my corsa sometimes strugles to start, then i get hesitation and EML comes on and power is reduced until i switch of the engine and the light has gone and power restored, this happens imtermitantly . on the occasions with hestitations its been on flat motorway doing 80mph and accelrating When power has been reduced and EML comes on its been when ive had 1/4 of a tank andhard accelration on inclines.

dealers is going to replace LP pump to try and rectfy this. is it true if the HP pump is on its way out there will be metal fragments in the fuel filter? just trying to gauge what it might be, the fault code is low fuel rail pressure and fuel system malfunction.

Edited by cdti on 08/11/2011 at 21:31

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Wed 9 Nov 2011 10:49
corsa cdti - could someone please explain about fuel pumps - injection doc

If the LP is failing it does starve the HP unit of fuel causing the power loss at higher speed. Replace the LP unit and see how it fairs. If they find metal fracgments because its been driven too long with the LP bot working and the tank has been run low then technically it will need the tank removing and flushing including all fuel lines & a replacement HP unit and injectors.

That is exactly why I never allow my Diesels to run much below half a tank. fuel is the only lubrication for these HP units

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Thu 24 Nov 2011 02:58
corsa cdti - could someone please explain about fuel pumps - 1litregolfeater

Interesting, I never knew a diesel might have two fuel pumps, sure clears up some terminology!

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Thu 24 Nov 2011 11:50
corsa cdti - could someone please explain about fuel pumps - jc2

Not all do!!!

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Thu 24 Nov 2011 20:03
corsa cdti - could someone please explain about fuel pumps - hardway

Dealer is going to "try" to fix it!!Equipment for testing the L/P pump isn't exactly high tech,a simple pressure gauge and a graduated container will do.ok,maybe they don't have a 'scope,they should have,but come on,I've tested a L/P pump out put on a breakdown with couple of bit of pipe,a compressor gauge and a Coke bottle!not exactly rocket science.and yes the pump then was shot,low pressure and delivery.Dealer is going to try to fix it!!

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