Waiting on my Foxwell NT510 diagnostic tool to arrive, but pretty sure it won't help me with my current problem with my 2003 Disco 2 Td5:

In the last week or so we have had an intermittent starting problem - seems to start effortlessly first time every time in the morning, but after a run and switching off the ignition and then trying to re-start again it doesn't fire first go anymore. Pretty sure starter motor (refurbished starter solenoid several months ago) and battery are all good (battery is only 5 months old and checks out okay with multimeter test). Also, installed new FPR several months ago as well and everything was good following that. Also, injector loom was replaced a few months ago as a precaution even though the loom and red plug connection at ECU was spotless.

So, intermittent starting issue has presented itself and this seems to coincide with a lack of power - engine doesn't really get moving until the accelerator is pressed a fair bit - a lot less responsive than it used to be.

What is the most likely cause? Don't really want to entertain a new fuel pump or injector seals - no reason to suspect either really (though I do confess to being a mechanical novice).

Seen this on the "LR Direct" website though and got me thinking a "possible (and likely) fix" might not be that expensive:

"Fuel filter head bleed valve WJN500110 is for the Td5 engine fitted in the Land Rover Defender and Discovery 2. The part number for the non-return valve fitted next to the bleed valve is VUB503950. Replacing these two valves can solve issues with poor starting engines."

Might check MAF with the multimeter - might explain low power at low revs when taking off; the MAF is the original one and I guess it is possible that I may have damaged it when I cleaned it with MAF cleaner several weeks ago? Not sure though if a faulty MAF could also lead to intermittent starting problems, and of course there is the unlikely scenario where I have two problems concurrently?

Is it worth replacing these two valves on the fuel filter housing? [Fuel filter is a Mahle and I changed 12 months ago.]

Looking for likely and cheap potential causes of this problem at this stage; if no result forthcoming then it's off to the LR mechanic I think.

 

Location:Australia

 

Okay, received Foxwell NT510 on Friday: pre-loaded with VW software. Used it on Saturday so I could change the brake pads on rear wheels of VW CC - so may have paid for itself already. Today, Sunday, I paid for and downloaded and installed additional Jaguar Land Rover software for 60USD.

2003 Land Rover Discovery 2 Td5 automatic transmission:

Okay, went out late this afternoon and found the "OBD 2" connector on the LHS of steering wheel (RHD here in Australia), low down, just above the left foot rest pedal. Turned ignition to position 1 - Foxwell NT510 booted up - all good!

Decided to try and start the engine. Well, engine started first go this time - no problems at all (and it's very cold today) - this fits with the intermittent starting issue. Let it idle for a little while (parked in driveway) and then decided to record live data. Decided to then squeeze the accelerator - engine was noticeably rough under light acceleration this time (slight rumble and rocking) and returned to normal when engine allowed to idle again. Got cold and dark very quickly outside so had to come inside to the warmth!

Anyway, these codes showed up on the Foxwell NT510:

Engine Speed outside bounds for cruise (Where Fitted) Active
Vehicle Speed outside bounds for cruise (Where Fitted) Active

Now need to read up on the NT510 manual, do a bit of internet searching and see if I can work out what my issue is unless anyone here has some ideas?

Started graphing live data and I thought I saved the graph, but when I looked I have multiple screens of tabular data on the Foxwell NT510. Anyway, at least I think I might have a chance of working out what the problem is now if I persevere? Any thoughts on what I need to look for now or tests I can perform?

Okay, printed this recorded live data out to pdf on laptop and copied here - recorded this while engine idling and light acceleration (as I mentioned, as soon as accelerator squeezed a little the engine seemed to then run a bit rough - slight rumble and rocking). Can't seem to find the live data graph I thought I recorded and saved at the moment - will have to have another go in days to come (though vehicle is low in fuel - so might have to top up with a gerry can rather than risk a drive down to the service station). Can't see anything here that stands out to me?


Diesel TD5, Read codes, ECU information, Live data, All data
Data list
Ambient pressure 100.66 kpa
Engine speed 774 rpm
Idle speed error 20 rpm
Vehicle speed 0 km/h
Coolant temp 26.8 °C
Inlet air temp 13.2 °C
Fuel Rail temp 19.2 °C
Mainfold pressure 102.62 kpa
Air flow 66.8 kg/hr
Driver demand 1 0.73 V
Driver demand 2 4.29 V
Driver demand supply 0.00 V
Turbo MOD % duty ratio 0.00
EGR MOD % duty ratio 0.00
Driver demand 3 4.64 V
Driver Demand pedal 3 Track
Clutch pedal position switch DEPressed
Low Ratio switch NOT in low ratio
Brake switch 1 OFF
HEVAC Aircon Fan request NOT REQUESTED
Aircon fan drive ON
HEVAC aircon clutch request NOT REQUESTED
Aircon clutch drive OFF
Cylinder No.1 2 rpm
Cylinder No.2 1 rpm
Cylinder No.3 -2 rpm
Cylinder No.4 0 rpm
Cylinder No.5 -1 rpm

 

Crank position sensor, coils, wires, plugs?

Have you adjusted the throttle cable?


I would like to add, I've had my truck act differently with different cps. I've put a brand new one in and the truck would run...but just felt sluggish, changed it to another and the truck would run better. Weird, but I verified this twice.

 

 

sounds like a fueling problem if its diesel...
When was the last time you replaced fuel filter?
How about air filter?
For diesel diagnostic work you need to be able to see high pressure fuel psi, maybe a setpoint vs actual pressure.
I have not worked on land rover TD5, but have worked on in-line 5 MB sprinters, cummins, 3.0 mb diesels, 3.0 ecodiesels, etc...

Always start with basics ie: fuel filter and air filter and go from there..... An intermittent starting proble could be an injector leaking down, low fuel pressure from high pressure pump,..there are so many things it could be...
Keep us updated..

 

Only 3,000km since last fuel (diesel) and air filter change. Gut feel is saying air bleed valve issue (that valve that sits above the fuel filter) or maybe the crankshaft position sensor???

Intermittent starting, uneven running under acceleration (lack of power)? As you said, many possibilities! Will check using Foxwell NT510 again and see what live graphical data looks like.

 

Am I right in saying that both a faulty CPS or a faulty diesel air bleed valve (sits in housing above filter) could result in intermittent starting (starts when cold, not warmed up) AND engine rumbling/rocking when under acceleration? Fuel filter and air filter now replaced as part of standard service I just completed (vehicle had new engine mounts put in a year ago so unlikely to be the cause of the mild rumbling/rocking when under light acceleration). I understand there are other possibilities - but am I right in assuming the CPS and air bleed valve are two of the more likely problems?

In the meantime will persist with the Foxwell NT510 and see if anything obvious shows up with live data graphing.

 

Also, new injector harness put in several months ago so checked around ECU again - no oil present. Also, sump oil level consistent and no smell of diesel in oil so suspect injector seals are okay.

 

First thing l would do is put some fresh fuel in it. You say it's low, may be pulling water or contaminated fuel.

Like mentioned, without reading high pressure pump values or being able to do a cylinder cut-out test...you are kind of just quessing at issues.

You may be better off seeking out a different site, one from the UK or something. Not too many LR diesel engine here in the states.

Good luck

Brian.