Hdi nightmare.

[quackers68]

Hi,

I have a 307 2.0 hdi 110, and planet said there was no signal from cam sensor, so i renewed cam and crank sensor's. Then there was a problem with the cam sensor wires, and it knackered the cam sensor, so i soldered new wires and put another new cam sensor on. Now the car went ok for a couple of days, then wouldn't start, so i put it on planet and it comes back with no camshaft sensor signal. The car starts and runs if i give it a sniff of easy start, and it will start of the key then if the engine is warm, but if i leave it till it cools down again (11/2 hours) it wont start. Today checked with a meter and the volts seem ok to the cam sensor, but the volts on both pins of the crank sensor are about 2 1/2 volts? This is really doing my head in now, so any help would be appreciated.

[Peter.N.]

I don't like to dispute what the Lexia says but your symptoms suggest low rail pressure, can you check that with the Lexia?

Peter

[CitroJim]

I would agree Peter, the fact it starts and then (presumably) runs OK after a sniff of easystart would rule out the crank and cam sensors.

Looks like a tired HP pump that needs to be spinning faster than the starter motor can before it brings the rail pressure up high enough for the ECU to declare all systems go. It may be the rail pressure sensor itself at fault.

Too much easystart is bad for an engine. They appear to get addicted to it...

[spider]

I'd agree they do seem to get addicted to it, I heard that years ago and did not think much of it but it is true. If that's caused by valve wear or something else I'm not sure.

I'd go with fuel pressure too simply as it runs when its been "treated" so it may not be getting the pressure up. I'm not up on the HP pumps but if I remember correctly they have a third piston solenoid to cut the pressure down. If this was stuck open perhaps the pressure would never get high enough to start it initially ?

[CitroJim]

Yes, I believe the ether upsets valve sealing and thus lowers compression and a vicious circle sets in. It does much the same harm as detonation (pinking)n in a petrol engine.

Good thinking on the third piston. It deactivates at high speeds to relieve the load on the pump. If it is always deactivated then it might cause this problem. I have a dim memory of a post a while back showing a problem with the filter basket around the third piston being blocked with debris from a breaking-up lift pump. It is normally a replacement job but the tread explained how to clean up the filter basket. Might be well worth a look but for the life of me I can't recall any more than that about the thread in question...

[DickieG]

IIRC on an HDi if the fuel pressure is too low, when the engine is turned off there is a slight delay before the engine actually stops.

[CitroJim]

IIRC on an HDi if the fuel pressure is too low, when the engine is turned off there is a slight delay before the engine actually stops.

Oh err, mine does that very occasionally...

[spider]

The XUD11's do that sometimes, a delay of more than about 2-3 seconds points towards a problem in the pump I think ? , I know they don't normally shut of as "quick" as the XUD9's given their pump arrangement (electronic accelerator) , I do recall one that would run for a while ended up having a pump.

Regarding the third piston, I was thinking although a diag session would pick it up if the solenoid was stuck, perhaps the valve itself is but the solenoid still moves, thereby as far as diag is concerned its operating. Random thought, hope that makes a bit of sense, another analogy of it would be a stop solenoid where the pin still moves but the plunger is stuck.

[DickieG]

IIRC on an HDi if the fuel pressure is too low, when the engine is turned off there is a slight delay before the engine actually stops.

Oh err, mine does that very occasionally...

Try the 'wiggle test' on the rail sensor and the pump pressure regulator Jim, failing that remove the pump pressure regulator and look for any debris accumulated in there and use a small magnet to grab hold of any metal particles, obviously absolute cleanliness is essential.

[quackers68]

I have only used easy start twice, just to see if it would actually go, to rule out timing isues( i don't like easy start).


So today i plugged the crank sensor back in, then stuck it on Planet so i could get the live data to report back here. When i did a global test it reported NO FAULTS, which kind of took me by surprise, so i then tried to start it and it started and has been starting fine all afternoon. So i can only asumg there was a bit of dirt in the crank sensor plug or something and thats why i have been getting the problems this last week. Hopefully it will be ok now, so thanks folks for your help.

[BX]

This thread is now idle for a while but here goes anyway.
The pressure regulator going faulty on the 2.0L 8V 110 usually causes over-pressure not low pressure.
The symptoms you describe are usually caused by low rail pressure at cranking speed. This applies to all CR diesels. Get the engine to turn over faster. It always cranks over faster once its warm
Try to bump start the car when its cold, idellay by letting it run down a hill. (Yes I know you shouldnt do it) or else use a booster pack or jump start the car off another vehicle. If that gives a quick start the low pressure is probable the cause. Then do a leak off test on the injectors to see if there is excessive leak off on any of them. If you have "planet" to read the rail pressure that's great, but practical tests often give a more definate answer. Certainly do not go running to the shops for replacement parts unless you have more evidence of their guilt than a diagnostic fault code.