Fuel Pump Timing Explained Please!!

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mattkim said:
Ok, so have checked the glow plug relay, all fine, and changed temp sensor. Just checked it against my cousins p38, both with fuel filters taken off, his is getting fuel straight away, whereas mine is after 4 seconds/when the glow plugs go off. Going to change the filter head, as I'm wondering if this may be the problem, if no joy there, I'm going to make up a new fuel line with a non return valve near the tank.
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Should only pump when the glow plugs are on and stop when they go off. Sounds like the pump is knackered.
 
mattkim said:
Ok, so have checked the glow plug relay, all fine, and changed temp sensor. Just checked it against my cousins p38, both with fuel filters taken off, his is getting fuel straight away, whereas mine is after 4 seconds/when the glow plugs go off. Going to change the filter head, as I'm wondering if this may be the problem, if no joy there, I'm going to make up a new fuel line with a non return valve near the tank.
Click to expand...

None return valve in the form of a primer bulb near the filter would make a lot more sense. Genuine lift pumps had an NRV in the pump itself. If the pump is weak it may struggle to get fuel past it. Newer after market pumps don't have an NRV in them. Well at least the OEM VDO ones don't.
 
As I put in my original post, I've put a new in tank pump in, my cousins pump is a £40 one and is working fine. Mine cost treble that but isn't pumping from ignition on. Just tried a genuine land rover in tank pump and still have the same problem
 
mattkim said:
As I put in my original post, I've put a new in tank pump in, my cousins pump is a £40 one and is working fine. Mine cost treble that but isn't pumping from ignition on. Just tried a genuine land rover in tank pump and still have the same problem
Click to expand...

It won't pump on ignition unless the glow plugs are lit. Only works from glow plugs when ignition is turned on. When they go out it stops until engine starts. Or when engine is cranked 1999 and on.
 
mattkim said:
The odd thing with it is that after 2 warms of the glow plugs, she strikes straight up. If I only do it once she cranks over for a few seconds, would this be fuel pump timing? All glow plugs are brand new Bosch (not cheap ****), and they have been tested and all working fine. I'm running out of options now
Click to expand...

Mine does this too. New glow plugs made it better but the first time in the day when cold she really needs 2 cycles. My suspicion is my FIP pump is tired or maybe my compression isn't 100% until the engine has warmed up a bit. I've given up worrying about it though. I'm too sh!t scared to take the FIP off so I'll wait until it breaks. :)
 
Got to the bottom of the problem, which was fuel run back even though I have a one way valve fitted. Thanks for all your suggestions.
 
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