X trail glow plugs

[revjames]

Trying to help out my bruv with his X trail 4x4 its a 2006 2.2TDi 4x4. Having difficulty starting so I thought it might be the plugs. Hard to get to so stuck a clamp meter on it (yes a DC one) and ther was initially about 30A but only for a second or 2 then it went down to just under 12A for much longer before timing out.

I'm no expert in auto electrics but I thought there would be much more current flowing than that. I thought they were about an ohm each which would be about 48A right? so I am assuming there are several not working but at least 1 working. Its a faff and intercooler would have to come off to get to them so trying to make sure before I order anything.

Thanks in advance

 

[apprentice87]

This is only a guess mind... I know that on some diesels the plugs stay on for some considerable time after the engine starts to make it run smoothly when cold. Could it be that the 30A was it thinking cold start coming up, then the rest was it thought or hoped it might be running....

john..

 

[Sharpend]

I'd be surprised if the glow plugs were causing the problem as the weather has been pretty mild and glow plugs are fairly ineffective in mild weather? Ideally you need to remove and test the resistance across them individually. 

Have you an auto scanner that may throw some light in the issue? 

Glow plugs only heat for a short period of time matter of couple of seconds or so. 

 

[SLIPSHOD & SLAPDASH]

I know my old Vauxhall   would  not start at all without the glow plugs, sometimes even only after 20 min without the engine running.

 

[revjames]

I know how glow plugs work, I need to know roughly how much current they consume as 12a seems a bit low

 

[ruston]

Does he just wind it on until it starts ? Direct injections should start off the key immediately.

 Glow plugs as has been said do cut in and out to aid cold running. Depending on model and ECU it will depend how the starting and cold running sequence is performed.

 As Sharpened has said it is unlikely that the glow plugs are causing this problem. Modern diesels are as complex as petrol  engines now , with all the same sensors  and devices that will cause bad starting. For instance if the air flow meter is giving the wrong data it will have a knock on effect to the other sensors and confuse the ECU.

  I have never worked on an X trail , and do not know if that year has a common rail . 

 Are there any other symptoms showing , before and after.

 

[ruston]

https://www.youtube.com/embed/pUNTFlfWw1M?feature=oembed

https://en.wikipedia.org/wiki/Turbocharged_direct_injection

Go to overview.

 

[revjames]

I was just told it wasnt starting very well, as this is a recent thing, I suggested perhaps glowplugs, especially with the onset of colder weather. Not sure if its common rail or not. hard to see as theres a great big intercooler on top of the engine. I am trying to work out from the current drawn if theres one or more faulty plugs. I measured from the point where the cable from the relay joined the copper bar across all the plugs. I thought they were about 1 ohm each which would have drawn 48a for all 4 but not sure. 

 

[revjames]

OK thanks for the replies. For clarification this is what I need to know

resistance of a typical glow plug (prefferably a nissan x trail one) so I can work out from my measured 12A how many (if any at all) are not working,

Thanks

 

[Sharpend]

https://www.picoauto.com/library/automotive-guided-tests/glow-plugs

 

[revjames]

Thanks Sharpy - From the example the combined load was about 50a so I'm guessing theres only 1 plug working. 

 

[ruston]

If it is a swirl chamber , you may still get the  reading from the glow plugs , but if it has a lot of miles and starting use the tips could well be worn away too.

https://www.boschautoparts.com/documents/101512/0/0/0b189154-b815-46d7-bf70-e153bb6ecb88

 

[steptoe]

Rev, you are getting too caught up in it being glow plugs, 

Does it smoke when it starts,?

If not, then not glow plugs,

TBH, glow plugs wouldn't make a bit of difference whatsoever in this weather.

Recently my van has taken a bit of cranking in the morning to start it,

Problem, dirty fuel filter, I replaced the air filter too as a matter of course,

The high pressure pump simply couldn't get enough pressure built up, 

 

[revjames]

we have had a few cold days up here and the problem has only recently surfaced. Its done 100K and never had a set so probably not a bad idea to put new ones in. But yes fuel air, oil and filters probably should be done too

 

[ruston]

If the air filter is clogged it will play havoc with the air mass flow sensor as I said before..

 

[Sharpend]

Sounds as though the motor may need a tlc service? My van has done 130k on the original set of glows before I changed them, starting was never an issue though. although my changing the plugs was only brought about after I found a damaged loom to the plugs. 

 

[ruston]

I have an old Ford Maverick I keep for the winter . It has the 2700 Nissan diesel engine in it . 185000 miles ,. It is not a TDI  and is off the key any weather.

 I have never put a set of plugs in it yet.

 The only time I had starting trouble   was because the non return valve in the filter head was faulty , allowing the diesel in the pump to drain back into the filter giving the symptom of out of fuel and air in the line.

 Cranking would start it , but with such a large engine it hammered the battery.

 With diesels the fuel filter is critical.

 

[steptoe]

I have an old Ford Maverick I keep for the winter . It has the 2700 Nissan diesel engine in it . 185000 miles ,. It is not a TDI  and is off the key any weather.

 I have never put a set of plugs in it yet.

 The only time I had starting trouble   was because the non return valve in the filter head was faulty , allowing the diesel in the pump to drain back into the filter giving the symptom of out of fuel and air in the line.

 Cranking would start it , but with such a large engine it hammered the battery.

 With diesels the fuel filter is critical.

Ah, that's something I never thought about with my own van, I'll see how it goes next few days, then I'll check non return valve, it started off the key today, but needed a crank yesterday, and Monday, only done filters on Sunday, so thought maybe some air bouncing around the lines, 

 

[ruston]

Could well be , also if you have a corroded ,weeping fuel pipe will give the same symptoms . 

 If you can park it head down the hill ,it helps stop the diesel running back into the filter as a temp measure.

 It used to be very common.A new filter head is the answer.

 To prove it you can put a plastic pipe in-line to the pump delivery and watch for bubbles running back to the filter.

 This is on the old style though , not the common rail.  But may still affect it as the low pressure pump requires cranked diesel.

 The pump gives a short burst on ignition on , then stops , it will only supply diesel after that during cranking.

 Assuming your van has an electric pump.

 The high pressure pump is charged , and is delivered to the common rail and metered individually to electronic controlled injectors within the parameters of the signals given to the ECU.

If this is not clear it is because it is late lol.