Freelander TD4 Auto 2005 NO START INTERMITTENT

[smallfry]

As title suggests, I have a problem with an intermittent no start with a TD4 Auto

I have read that this is a not unusual problem with the "ultra reliable and bulletproof" BMW engine...……………….

It has left me stranded at a fuel stop, causing chaos at the pumps, at the supermarket, at work, and at home.

I have learned that the prime suspects are the camshaft sensor, the low pressure fuel pump, and the injectors. So first things first, I did a cold compression test (couldn't start it) and all cylinders came between 400 to 410 psi, so that's OK I think. Checked the injectors for leak off, both with engine running, and without. All were more or less the same, and not at all excessive, so again, OK I think.

Then, being that we also have a fully functioning second Freelander, I have tried some component swapping...……….

Up to now I have tried (one at a time) camshaft sensor, crankshaft sensor, pressure regulator on HP pump (using new O ring), boost pressure sensor, fuel pressure sensor on rail, plus wiring loom modification for it. Low pressure fuel pump under wheel arch and replaced the fuel filter, which had been installed the wrong way round. also installed new glow plugs.

None of which seem to have made a difference. Always difficult with intermittent faults in any case. Thought I had made a breakthrough when I discovered that there was some oil that had worked its way up the wiring harness to the engine ECU and had settled in one of the connector plug "wells" Cleaned it all up, treated with contact cleaner, and checked inside the ECU to see if any had got inside. It hadn't. Still wouldn't start.

Considered the immobiliser, but as the engine actually cranks I think its working correctly ? (I took the chip out of the key and tried, but the engine doesn't crank) I really don't know where to go with it now. I cannot see that a faulty MAF sensor would prevent it starting, and if the injector/s or HP pump were faulty, they would be faulty ALL the time ?

When it does start, it runs with no problems at all, no matter how far you go, and starts instantly.

Thinking about it though, and trying to find a pattern to it, bearing in mind the recent HOT weather, I have found that it will start in the early morning when its cool. I can turn it off and try again in a few minutes, and it will still start. BUT, if I then leave it until the middle of the day when its hot, it will not. Then if I leave it until the next morning, it will start again. But if I then leave it a whole day, and try it in the middle of the next day or the evening, it will not start again.

So it SEEMS that it temperature related (not the engine temperature) but I am not sure about this. 

I have ordered a scanner, which I am not sure will help with this much, but anyone got any ideas in the meantime ? It driving me up the wall !

 

 

[garrycol]

What do the codes say is the issue?  This is really the only way to start to look for engine issues.

[FridgeFreezer]

Crank/cam sensor would be my #1 suspect, they can fail when warm (contact expands & moves apart) and then be perfect when cold. People always say "injectors" for TD4 faults but the odds of all four injectors suddenly going faulty are ridiculous and as you rightly say, a dodgy MAF etc. would not stop it, it'd just run badly.

There is the LP pump in the tank and the HP pump, I believe both/either can cause issues and there's an early and later version of the setup, but those cost way more than a crank or cam sensor - start on the cheap bits if nothing else!

[tobac]

Had a 2001 petrol that had lithe same symptoms. Couldn’t find the cause. Finally turned out to be a faulty key switch connected from memory. It would crank but not fire up. Always worked when cold but intermittent when hot. Good luck.

[Ally V8]

The problem you are going to have is that a scanner is pretty useless during cranking.All you will get from it will be fault codes,which may or may not help.Best to clear them and start again,then view the codes after the first no start situation. live data from the scanner will help in terms of what the ecu can see with the ignition on,but not cranking - compare with your other car for good values. A scope is what you need to really see what's going on when cranking,something like a Picoscope. I say this because you can set it up,monitor whilst cranking and then replay the scope traces to see exactly what happened. Connecting the scope to sensor outputs at the ecu end,a close to the plug as possible always helps,and as close to actuators as possible.

You have covered most of the usual suspects,but it might be worth checking the plug that connects to the end of the rail pressure sensor,these are prone to poor connections ,especially when the engine is rocking around while cranking. There is an official LR repair harness for this plug.

[smallfry]

Thanks for the replies gents. Scanner not actually here yet !

As I suspected, I tried it when I got home this evening, but as the temperature is only 14 degrees here, it started no problem.

Have already tried all the things suggested, except the ignition switch, and when the items are put on the other Freelander, that one still starts no problem. 

I suspect that its something inside the cabin rather than the engine itself.