406 hdi 90 intermittent starting problem.

[Alfow]

Hello all

I am a long time lurker and thanks to the car being bloody reliable I haven't had much need to post - until now!

Since replacing the in tank pump for the second time the car has developed a starting problem.
Sometimes you can jump in and she fires up straight away hot or cold. Sometimes you can get in and she will just turn over with no signs of life, sometimes she will fire briefly (1-2 secs) then cut out. There seems to be no pattern to this.
The fuel filter is new as is the battery. However at the petrol station the other morning she refused to start after being run for 45 mins, not even briefly firing, managed to get a jump off of somebody and she fired up straight away. I suspected the battery being duff so swapped it for another new one - same symptoms. Charging system is working correctly - 14.4 V when running.

Have checked the cam sensor and will be taking the fuel pressure regulator later off today for an inspection and clean.

Any thoughts on this?

Any input greatly appreciated.

[annie]

is the pressure staying at the rail. sounds like fuel pressure bleeding away. did one on mine a while ago and it was the lifter pump one way valve had failed letting fuel drain back into the tank

[PeterN]

The regulator on the HP diesel pump can give problems, when mine failed it would start reasonably well from cold but eventually became almost impossible to start when hot.The problem seems to be the filter in the regulator, the holes are so tiny you cant see them which makes it very difficult to clean. As some regulators don't have a filter I removed the one from mine and its been fine since.

Peter

http://www.ebay.co.uk/itm/FUEL-PRESSURE ... 3aaa4fc2cc

[Alfow]

Thanks chaps.

I removed the pressure regulator lastnight and it appears to be the type without filter.
Am I right in thinking that when this is working correctly you should be able to hear a slight rattle when it is shaken? Like a pin moving up and down.
It looked pretty clean, I removed the o rings and left it soaking in WD40. Will go back to it later today.

As for the lift pump, where would I find the one way valve on this? It's a brand new pump so i'd be surprised if it had failed but you never know!

[annie]

on my other older cars the valve is screwed directly into the outlet of the pump body and the outlet hose connects to that. i wont be the valve if the pump is new i think though

[Alfow]

So I put the pressure regulator back in but the same symptoms still persist.

I have managed to identify one consistent inconsistency though. If you switch the engine off by turning the key to ACC she will restart quite willingly, I did this probably 20 times with no problem.
If you switch off by turning the key all the way off then try to restart she is very reluctant to start, either turning over and over or attempting to start but not quite making it. If I switch back to ACC from this 9 times out of 10 she will start!

Any thoughts?

[PeterN]

Sounds like a strange electronic fault, possibly the engine ECU, or, I wonder if it could be a faulty ignition switch? That would be the easiest thing to check first. See if you can gather any more symptoms.

Peter