Once again the cutting out has reared its head, had to be transported back this morning. OBD say crankshaft position sensor, which it said some months ago and replacement cured if till now. One other question on cranking the engine should fuel come out of the pipe leading from the tank into the filter?

It might depend on the quality of the cps.
I replaced a failed camshaft position sensor with a cheap Italian made part which was supposed to be guaranteed for 5 years..
Failed after 8 months.

The supplier says I was very unlucky and they are sending out a replacement. The price difference is quite large though £12 for the one fitted as opposed to over £100 for the LR one, which they obviously do not make themselves.

The cheap cam position sensor I bought was £18. Th LR one was £70,
Just checked my records. The cheap only lasted 5 months.
Nuff said.

Double post

Dam, I've just brought a delphi one as backup,
I knew I should have invested more.  DAVE.

Bogart wrote:

Once again the cutting out has reared its head, had to be transported back this morning. OBD say crankshaft position sensor, which it said some months ago and replacement cured if till now. One other question on cranking the engine should fuel come out of the pipe leading from the tank into the filter?

Had the same problem for the last 3 years. The occasional "misfire" / cutting out was so concerning I started carrying a spare crankshaft sensor with me just in case. Purchased 4 genuine crankshaft sensors before I got to the bottom of it, thinking they were either faulty or something was killing them.

Like many before me trying to work out what is causing this I replaced the fuel filter, chased the air bubbles in the fuel line, cleaned the throttle body, reset the throttle pedal, cleaned MAF sensor, cleaned the earth contact, installed second earth cable etc all to no avail.

It turned out to be just a faulty loom plug (bad connection). The connection is lost under certain conditions. To fix it I made extension cable from the sensor pins to the loom plug. I've included a photo to give an idea of how it looks. Essentially I purchased a kit on ebay that allows you to make up your own automotive electrical connectors. The connectors of course do not fit but the end male and female metal pins do.

I used three short cables, about 12 cm each (got mine from an old computer power supply). Each cable is terminated on each end by male and female pins (soldered), and shrink wrapped to insulate. It's not pretty but the car now works like a clock.

If anyone has an idea how aesthetics of the plug can be improved without buying another wiring loom please share.

Click image to enlarge

Click image to enlarge

 MY10 TD4 SE Auto

Fitted a new crankshaft position sensor and all good again, for now. Now was I just unlucky in the previous one failing after a few months? What worries me is on Wednesday after the first cut out and a 30 second wait it started again and did another mile
then died permanently. I could refit the other one and try again, but guess what cannot be bothered. Always possibility of the wiring being dodgy.

The crankshaft sensor connector / plug has a small amount of up and down travel (about 0.5mm) when fully inserted and locked. I was able to demonstrate that the connector was not working as it should by moving the connector (with the engine off) along its path of withdrawal without releasing the lock/latch. With the plug in this position (about 0.5 mm up from its fully seated position, with the lock still fully engaged, at the upper limit of its free travel) the engine did not start - just kept on turning over.

When I pushed the plug all the way back in (along the path of insertion - about 0.5mm worth) the engine started just fine. I repeated the process 4 times and got the same result. I concluded that it’s entirely possible for the plug to move sufficiently while driving for contact to be lost.

I tried moving the plug with the engine running but that did not do anything. Not certain why, possibly not as sensitive at relatively low RPM?

I also measured width of pins on the sensors I’ve accumulated. Pin width on the sensor that came with the car in 2009 is 1.53mm. Pin width on the new genuine LR sensor is 1.49mm. Not sure if this difference in width is sufficient for contact to be lost when certain conditions are met but ever since I modified the plug (as described earlier) I have not had a problem.

Hopefully this helps someone. MY10 TD4 SE Auto

Interesting you mentioned about plug movement. The new one appears to be much more firmly fixed in the socket than the one removed. Pushing the plug in it felt as if it had definitely got home, time will tell. Regarding the pin width I suppose one could always tin the pins. Twofold bonus less chance of corrosion and possibly a much better contact with the plug.

Decided this morning to change back to the old sensor. Guess what? Yes started fine. Wiggled sensor plug wiring no faults.
I hate problems like this. Am going to tin pin connections on the new sensor after dosing the plug with lots of contact cleaner.
Have no idea where these 3 wires disappear off to. Will drive around a bit with the splash shield off so if I get problems hopefully a quick unplug and plug in of the wiring might sort it.

Bogart wrote:

One other question on cranking the engine should fuel come out of the pipe leading from the tank into the filter?

When you say "tin the pins" do you mean flow solder over the pins to make them slightly bigger, and thus hopefully improve contacts? If so I though about doing that but decided against it as wasn't sure what all that heat would do to the insides of the sensor.

If you decide to try my method let me know and I'll try explaining in more detail.

Also, if you want the fault with the plug to become even more apparent remove the silicone water seal within the plug (you can put it back later). That way when you move the plug as I've described in my previous post (with the engine off, not while it's running) it won't recoil back by itself due to elasticity of the silicone. When heated, silicone becomes more plastic and therefore doesn't offer the same degree of "recoil" when you're driving around, so the contact is more easily lost. This can be easily confused with your classic symptom of crankshaft sensor failure. MY10 TD4 SE Auto

jules wrote:

Bogart wrote:

One other question on cranking the engine should fuel come out of the pipe leading from the tank into the filter?

No, the fuel pump is on the engine and sucks fuel through the filter. The pump in the tank is to maintain fuel levels on both sides of the tank; its saddle shaped, sitting over the driveline.

impact wrote:

When you say "tin the pins" do you mean flow solder over the pins to make them slightly bigger, and thus hopefully improve contacts? If so I though about doing that but decided against it as wasn't sure what all that heat would do to the insides of the sensor.

If you decide to try my method let me know and I'll try explaining in more detail.

Also, if you want the fault with the plug to become even more apparent remove the silicone water seal within the plug (you can put it back later). That way when you move the plug as I've described in my previous post (with the engine off, not while it's running) it won't recoil back by itself due to elasticity of the silicone. When heated, silicone becomes more plastic and therefore doesn't offer the same degree of "recoil" when you're driving around, so the contact is more easily lost. This can be easily confused with your classic symptom of crankshaft sensor failure.