My 2003 Defender 90 TD5 is starting hard (turns over 20 times or so before starting when cold) and feels like it doesn't have the top end power after I hit 80km/h trying to get to 100km/h.

I just replaced the fuel pump, filter and fuel pump relay. Had a gauge on the fuel line to confirm the pressure is good.

Found some oil in the red connector on the computer (cleaned it out). Found this because the Defender would stall out after driving 4 km, then take a minute to restart.... cleaning the connector has remedied the stalling gout every 3km... but now it still starts hard and seems to have lost a little top end power.

Suggestions on where to look? Is it possible the oil getting to the red connector has gotten into the computer and cause issues? I wasn't able to get the lid off the computer to confirm.

If it is hard to start with what you have already replaced it is likly to be building file pressure back up. If you turn ignition on and leave for 10sec does it start easier than cranking straight away?
Are the glow plugs functioning correctly? I am not as familiar with the td5. I know tdi’s did not really need glow plugs but the old td and my 2.25 diesel will not start without them.

dag019 said:

If it is hard to start with what you have already replaced it is likly to be building file pressure back up. If you turn ignition on and leave for 10sec does it start easier than cranking straight away?
Are the glow plugs functioning correctly? I am not as familiar with the td5. I know tdi’s did not really need glow plugs but the old td and my 2.25 diesel will not start without them.

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I turn the ignition on until the glow plug dash indicator goes out.... I haven't tried leaving on for 10 secs after that... but will try it....

it's also lacking in top end power, just sluggish compared to normal. Is it possible it jumped timing? sometimes with the hard starting I have to hold the key even when it feels like its starting to fire up.... almost like the old VW's when you would advance the timing when starting them.

JockHiltz said:

I haven't tried leaving on for 10 secs after that.

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leaving it on for longer is to let the fuel pump run longer before starting to see if it is a fuel bleed back issue and it meds to reprime each time.

Try carrying out a fuel system purge/bleed before starting, if it starts ok then you will be getting air in the system, video link attached that may help.

Scooby22 said:

Try carrying out a fuel system purge/bleed before starting, if it starts ok then you will be getting air in the system, video link attached that may help.

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Ok this is helpful... I didn't realize there was a purge cycle like that, by pumping the gas pedal... That noise from the fuel pump, is that normal sound or just the sound when purging? I just replaced my fuel pump as the old one was screaming, so I don't really know what a normal sound pump sounds like... new to the Defender world, drove jeeps the past 20 years.

Thanks again

JockHiltz said:

Ok this is helpful... I didn't realize there was a purge cycle like that, by pumping the gas pedal... That noise from the fuel pump, is that normal sound or just the sound when purging? I just replaced my fuel pump as the old one was screaming, so I don't really know what a normal sound pump sounds like... new to the Defender world, drove jeeps the past 20 years.

Thanks again

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You should hear the fuel pump kick in when you turn the ignition on, and if you leave the ignition on and do not start the vehicle you should then hear it stop again after about 30sec. It should not be noisy and should not be easily audible with the engine running unless there is something wrong with it. It is likely to be noisier during the purge cycle than in normal running.