Thread: TD5 Guru / Brains trust required

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.

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

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

Originally Posted by 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.

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

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

TD5 Disco Fuel pump/sender unit - Land Rover Technical Archive - LR4x4 - The Land Rover Forum

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

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.

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.