Xantia HDi hair dryer start

[graham1701d]

Hi,
Some time ago I posted about my Xantia HDi struggling to start after being left over night when the temperature was 4 degrees or less. After not really getting anywhere with this fault I have resorted to waving the hair dryer about. Having tried aiming the dryer at everything from the fuel filter housing to the coolant temperature sensor we have finally discovered something that works. If we warm the device that sticks out of the top of the high pressure injection pump with the orange plug at the top of it(I don't know what this is)it will start after a few minutes of warming. The fuel inlet for the pump is also quite near to this so I'm not sure if that has helped with thinning the diesel.
Can anyone help in why warming this device would allow the engine to start, or at the very least what this device is? Thanks.

Regards Graham

[citronut]

are you using vegy /bio diesel by any chance ??????

[graham1701d]

Hi Malcolm,
No absolutely not. I know it kills vital parts of the injection system on the HDi.

Regards Graham

[Peter.N.]

If this is the pressure regulator you will probably find that the filter is blocked, warming the fuel will decrease its viscosity and enable it to flow more easily. I have never had any success cleaning the filter so changed the unit, they are around £100 new but much cheaper secondhand off ebay. One of the regulators I had didn't have a filter so I removed the one from the faulty reg and its worked fine since.

Peter

Does it look like this? http://www.ebay.co.uk/itm/0281002493-PU ... 2c77b818bb" onclick="window.open(this.href);return false;

[BX]

The unit on the top of the pump that you are heating is most likely the third piston deactivator. It is operated by the ECU at high engine revs to save energy and thus reduce heating of the fuel. The pressure regulator is on what I would call the rear of the pump (opposite end to the timing belt). In my opinion a blocked regulator filter will not cause starting problems. It will cause the car to cut out. This topic is covered in several threads.
The first thing that happens in cold weather on EVERY engine is that the cranking speed is reduced. This is due to lower battery efficiency, higher oil viscosity and generally greater friction in the cold engine.
These faults must be approached logically.
First ensure that the cranking speed is sufficiently high. If the car has a Bosch injection system most eobd readers will give this information in live data.
The next thing to check, is the fuel rail pressure.
If the cranking speed is below 200 rpm it is unlikely that sufficient fuel pressure will be generated.
If the cranking speed is high enough but fuel pressure isn't then you have to check to see where it has gone.

[graham1701d]

The cranking speed is high enough. 300rpm. The car has been put on a Lexia and has shown no faults in codes and live data. Everything is fine except it won't start when it is stone cold below 5 degrees unless the area of the HP pump I said is warmed with a hair dryer for about 5 minutes. When it is turning over it will usually(although not always) will fire once or twice, the rev counter jumps to 500rpm, but it will not catch. Once the engine does start it can be shut off and immediately restarted. Other than cleaning the regulator filter somehow is there any other filters inside the pump that can be cleaned? I realise this fault is a bit unusual with what people usually encounter but I feel as if I have exhausted all possibilities without possibly changing the HP pump. I cannot understand why it will start when the HP pump is warmed. It shouldn't make any difference. Thanks.

Regards Graham

[Hell Razor5543]

I cannot recall the pressure requirement, but if there is not enough pressure on the fuel rail it will not start either. I do know that it is a very high pressure requirement.