Freelander 1 Difficult starting when cold TD4 - Solved

Been having an ongoing issue with excessive starting time when cold....fine when hot.

Engine turns over for ages before it catches and fires....runs rough for a bit but then settles and is ok.

Had to do some other work which involved removing inlet manifold so used the opportunity to change glowplugs....all 4 of which were faulty....broke one.......but 3 changed.
If I turn the glowplugs on using my diagnostics it now battery draws 45amps rather than just 6amps..so this seems ok.

However--- what I did notice from diagnostics was the "Boost Temperature Sensor" was reporting as 115C....which as the engine wasn't running and hadn't been since yesterday I found to be unlikely.

I am assuming this is the sensor at the front of the engine where the big rubber pipes connect to the inlet manifold.

There are no codes on my diagnostics, but I do get 2 if this is unplugged.

Any thoughts if this would cause poor starting....?

Does it restrict the fuel if it thinks the temperature is a lot higher than it actually is ?

Kevm said:

Does it restrict the fuel if it thinks the temperature is a lot higher than it actually is ?

Click to expand...

i reckon it could ..
the ecu will calculate air-density .. and air temp. be part of the calculation.
high air temp. = less air density = less oxygen available.,
which = more emissions if the fuel input is not governed somehow.
...
in theory .. with an very high air-temp reading like that,
it should be rather sluggish on acceleration .. i.e. once started.
..

Check the low pressure and high pressure fuel rail readings before digging deeper.

Got battery on charge at the moment but last readings were

Low 364kPa & High 28,659kPa

Thinking back I did have a split in one of the turbo hoses ( the one that connects to the Boost Temperature Sensor ) at around the same time this started.
Hose was repaired at the time which cleared the alarm that had been raised....may just be coincidence.

Ok looked at codes again....

Boost Temperature sensor 112 C...

Unplugged it went to 125 C....

Activated glowplugs via diagnostics ..... started instantly...

So it looks like the sensor could be preventing glowplugs coming on ( may not be red herring ...but I am going with this ).

OK tried my little Autel tester and it says IAT which I am assuming is intake air temperature is 3 C this seems more believable.

It must be something else thats stopping the glowplugs coming on

Well it started instantly today even though car is covered in frost.

I can only assume that it was just the glowplugs and that first struggle to start after changing them was probably loose crap in the air intake system after giving everything a good clean.

I will see how it goes.

Note:.....If your diagnostics tester gives unlikely readings....get a 2nd opinion

OK, so have had this in the past.

It appears that the glow plugs might be protected to protect them. They work better after a time. I now burn them on a battery before fitting, it tests them too !