TD5 Guru / Brains trust required

[ntguy]

OK so new TD5 I have brought has some problems.

It was running fine for the first 300 odd kms.

Then it started to have a slight miss from idle when taking off.

Then I lost all power and it was like it dropped a few cylinders. Nanocom showed the cylinder balance was all over the shop.

I had no choice but drive it like this,with a few times it dropped to idle. So with about 70 percent throttle i was driving along the side of the road at about 20k per hour.

All of a sudden it regained full power and lasted long enough to get it to mates place.


I have swapped out the FPR and the injector loom. I have checked the intercooler hoses.

Also checked ECU, there was some oil, nothing inside. But sprayed it all clean including both ends of plugs etc.

Sometimes it will idle OK, other times it idles roughly.

Its running like missing cylinders etc. But sometimes comes good?


No faults logged on Nanocom

Any clues???

[bsperka]

Others may have better advice. I'd start by saving the engine instrument values when its running normally and compare these to when its faulty. It would be great if on same road / conditions, but this rarely happens.

[sierrafery]

As no faults logged and bad injector roughness IMO the fuel pump's HP stage is gone and it doesnt deliver ennough pressure cos the ECU is trying to compensate on the injector ballance for it... if you can addapt a fitting to a gauge as to be able to screw it instead of the FT sensor in the FPR and measure fuel pressure....if you get below 4 bar then that's it, new pump needed

[ntguy]

Cheers, I dont have a fuel pressure gauge. But would a Fuel Pump be intermittent?

I have another vehicle for spares, so thinking of pulling the Fuel Pump off that and see if it fixes it.

Trouble is trying to work etc. Car is at mates place, spare car is around 30kms away and I live around 50kms away.

So after work will go to other car and get pump

[ntguy]

Others may have better advice. I'd start by saving the engine instrument values when its running normally and compare these to when its faulty. It would be great if on same road / conditions, but this rarely happens.

I am not that confident to drive it on the road...... At times it has no power. Just getting up a small driveway it can struggle.Other times its sort of OK

[sierrafery]

If it's not the pump it might be leaking injector washers

[Pippin]

TD5 Disco Fuel pump/sender unit - Land Rover Technical Archive - LR4x4 - The Land Rover Forum (http://forums.lr4x4.com/index.php'showtopic=54796)

Sounds like the pump and it can be intermittent, if you have not changed the pump before the above link will be very helpful.

Nick

[strangy]

D2's typically have a very good electrical system however as they get older a few points on the wiring loom are ignored and can be the problem.
Don't jump to throwing parts at it straight away.
Check the loom from the injector harness where it joins in the main loom, it is low down. Pay close attention to the area between engine mount and steering box.
Likewise across the gearbox bell housing. A box being removed clumsily will often cause damage to wiring.
Ensuring hands are well clear of moving parts, give these a good wriggle while the motor is running.

There is a thread around somewhere of similar probs.

[peter51]

The TD5 wiring looms are poorly designed and the insulation tends to rub through at several places.
Because it is an intermittent fault and assuming that the engine mechanicals are in tip top condition you first need to carefully check the following ? and I mean with a fine tooth comb. It should take an hour of cleaning and careful inspection on the main looms.
Have a look at the two attached photos ? one of which is the CKP wire ? which is the key wire in the whole system. Both these are the sorts of issues you are looking for first. Forget about fuel pump pressure at this stage. That is later
The following is a small except from a guide I wrote for my sons on diagnostics.
1. Circuit wiring
a. Wires and connectors to and from sensors or actuators must have negligible resistance/voltage loss/current attenuation under load. (The most common fault causing OBD codes is poor wiring or poor grounds, wires worn through touching the body, inaccurate/intermittent reference voltage feeds to the sensors/ actuators/ coils/ solenoids etc.)
b. 5 Volt reference voltages delivered to sensors are stable and accurate.
c. Control circuits are supplying correct control voltage and sufficient current flow to high load devices such as injectors, fuel pumps and ignition coil feeds.
d. All earths have negligible resistance or voltage loss under load in 4 places ?
i. the earth return wiring,
ii. splices where earths combine,
iii. earth wire to terminal integrity, and
iv. Between terminating bolt and chassis ? metal corrosion.

So you need to check all this stuff first. Its a pain but essential.

[jwb]

If it's not the pump it might be leaking injector washers


X2. Sounds like symptoms I had and once fuel pump was eliminated as a potential the injector washers fixed the problem

[peter51]

You also need to check for any oil/diesel or coolant corrosion in the AMP/TYCO connectors. These are the connectors which attach to all your sensors etc.
Oil or diesel can accumulate in the CKP sensor terminal and this will affect the waveform that is sent to the PCM. This waveform is attached.


Condition of the terminals is very important as alluded to in my post above. Attached is a picture of one AMP connector in good condition (left), however one on the right with bad terminal separation can lead to voltage drop which will affect the signal/voltage to the PCM. Such separation can be caused by continual removal(MAF in this case as I recall) - or by some useless person inserting mutimeter pins into the front of them. They must only be probed from the back of the terminal to avoid such damage.
Unfortunately some connectors, as BMW use(some TD5 connectors), weren't made to be serviceable. The housings may have a single slot for an extraction tool, but in the case of the Junior Power Time (JPT) receptacles which have 2 lance tabs(below) it can be impossible to remove the terminals from the housing without breaking it ? I have bought the supposedly correct tool from ebay without being able to remove some of these terminals.
So wires and terminals first before any other changing out of parts is where everyone should start first with intermittent engine issues.

[Pippin]

In my opinion it's best not to over complicate finding a solution to your problem, that can become very frustrating. As you have a spare fuel pump it is simplest to fit it as a first step.

Nick

[discorevy]

Agree with pump / inj washers ,also check cam timing , the head may have been off before and set up wrong , done a few like that

[sierrafery]

You also need to check for any oil/diesel or coolant corrosion in the AMP/TYCO connectors. These are the connectors which attach to all your sensors etc.
Oil or diesel can accumulate in the CKP sensor terminal and this will affect the waveform that is sent to the PCM. This waveform is attached.


Condition of the terminals is very important as alluded to in my post above. Attached is a picture of one AMP connector in good condition (left), however one on the right with bad terminal separation can lead to voltage drop which will affect the signal/voltage to the PCM. Such separation can be caused by continual removal(MAF in this case as I recall) - or by some useless person inserting mutimeter pins into the front of them. They must only be probed from the back of the terminal to avoid such damage.
Unfortunately some connectors, as BMW use(some TD5 connectors), weren't made to be serviceable. The housings may have a single slot for an extraction tool, but in the case of the Junior Power Time (JPT) receptacles which have 2 lance tabs(below) it can be impossible to remove the terminals from the housing without breaking it ? I have bought the supposedly correct tool from ebay without being able to remove some of these terminals.
So wires and terminals first before any other changing out of parts is where everyone should start first with intermittent engine issues.
I completely agree with that^^^ just that IMO it's not the case in this particular issue as here no fault codes are logged which i doubt that would be the case if there was some bad contact in the management area.... missfire with no codes usually means fuel delivery issue and the most common are the pump or leaking injector washers when combustion backpressure mixes up the fuel supply

[ntguy]

Injector seals are beyond me.....

Fuel Pump I think I can do. So will try and give that a crack on the weekend.

If that doesn't fix it, then need to find someone to do the seals.

I will order them just in case and new rocker cover gasket.

[crash]

What is it like to start after sitting for awhile? Do you need to go through the "priming" sequence before starting?
These were a couple of other symptoms I had with mine, as well as loss of power for no apparent reason then resume proper running - and intermittent swell. The result was leaking injector washers - and at around the same number of K's as yours.
I would swap fuel pumps and if that does not work - I would consider replacing the injector washers.

[ntguy]

What is it like to start after sitting for awhile? Do you need to go through the "priming" sequence before starting?
These were a couple of other symptoms I had with mine, as well as loss of power for no apparent reason then resume proper running - and intermittent swell. The result was leaking injector washers - and at around the same number of K's as yours.
I would swap fuel pumps and if that does not work - I would consider replacing the injector washers.

To date now problems starting. No need for priming etc.

I have only done 300 odd kms on the vehicle so not sure of its past. Spoke to previous owner and he did have a incident where it lost power. He let it sit for a few hours and it came good.

My experience was in my first post. It hasn't recovered from this loss of power. It did for a short period in getting it to mates shed.

At idle it can sometimes sound OK, but other times it runs real rough. Trying to drive it is like try to run on a few cylinders.

No faults listed on Nanocom. I am no expert with the Nanocom. Only thing obvious is the cylinder balance, one can be +30 and the other -30

[DazzaTD5]

As there are no fault codes listed I tend the agree with the most common issue as most have mentioned, the lift pump in the fuel tank, its also the easiest to replace.

Just some info..
*While the fuel pump may produce the required pressure if tested, it can be a lack of volume.

And as mentioned all over this forum, only replace it with a VDO branded pump assembly.

Regards
Daz

[ntguy]

Cheers Dazza, still need to get to it......


I have a D2a thats been tipped on its side and will borrow that one to see if it fixes things