TD5 110 INTERMITTENT POWER LOSS

TD5 LOSS OF POWER - ANY SUGGESTIONS WELCOME!

Hi everyone,

So I own a defender 2004 td5 and it's been great engine wise up till recently.

Its developed a very intermittent power loss issue. It doesn't matter so much if the engine is cold or warm, around 50mph (But not always) you can start to hear almost a puffing noise, and with that comes a big loss of power which has steadily been getting worse and worse, up till recently it hadn't cut out completely but yesterday it left me stranded in the middle of a roundabout. Any acceleration is met with more "puffs" and a loss of more power, changing gears doesn't help. I have attached a video, in which hopefully you can hear the noise.

What I have checked so far;

All hoses leading into and from the turbo for holes, all seems to be fine. Checked with soap and water (although the fan blows it around so violently its hard to tell), visually and by touch. Removed all hoses and checked for collapse inside the hose.

Maf and map sensors which are giving correct voltages.

Changed the fuel and air filter (as they needed it anyway) - cleaned the air filter housing while I was in there. Followed by purging the air out of the fuel system (5 pushes on accelerator pedal).

Checked the exhaust manifold for leaks - small hole found with soapy water but no blackening around it or loud noise escaping so I've been told it's likely not this. I did find a small hole in the exhaust on the box nearby the clutch slave cylinder which i know wont be helping power, but as this is after the engine i am pretty sure this isn't the fault.

Checked the turbo wastegate and actuator for play or stickiness and both are as they should be.

Booked it into a local specialist who at first plugged in a diagnostics to have it not communicate at all with the reader at all. They then tried a different device which brought up some faults but nothing that they could really work with apparently.

Checked the wiring under the seat box close to the plug for the ecu - found oil on the plug so have cleaned the wiring harness in the cab, and in the engine bay of oil multiple times now, and changed the injector harness for a new one complete with all new seals.

Cleaned all ecu plugs and relevant injector harness plugs with contact cleaner multiple times.

Opened ECU and saw no oil that had got in, cleaned it anyway and after the injector harness didn't fix the issue, ECU was sent for testing and repairs. They rebuilt the communication section of the unit and have returned it but the problem still persists.

The specialist did say that on testing one of my injectors wasn't exactly 100% healthy but he didn't think this would cause the power loss, especially as intermittent as it is. Other than this he said for an engine at 190k it was healthy.

Checked all volts/voltage drop at the fuel pump, all is suggesting the pump is okay and earth is not too bad either.

Checked fuel pressure at the FPR as the key was turned but not started, got just over 4 bar, and then tested again during the 5 pedal pressed purge sequence and got a similar reading.

Replaced one of the small valves on the fuel filter unit, small plastic piece with a red rubber tip, and while doing so checked all of the other brass fittings for blockages - all clean as a whistle.

Any help would be greatly appreciated as I'm running out of local specialists to book it into, (and don't have that much spare cash) and have tried all options friends and I can come up with on the driveway. Time isn't so much of an issue, but not being able to drive it is killing me!

A friend has very kindly sent me what he knows to be a working fuel pump which should arrive in a few days, will fit this and see if the problem persists just to rule out the fuel pump once and for all.

I am plucking up the courage to take the fuel lines off one by one and check for blockages (i'm actually not that mechanical at all so this has me on edge a little bit)

My last and most expensive option is a new injector/refurb the old one but due to the price i wanted to explore every option before giving in to this.

Any comment or suggestion would be amazing!

Many thanks!

Have you used the search function on this site? Not a TD5 user myself but lots of info here.

After you had the comms on the ECU reworked has a Nanocom been plugged in or was it a different diagnostic tool used, the live data may be interesting

@tottot i haven't yet but will be looking into that shortly. @JimS not since the ecu was returned, the LR specialist originally had issues connecting using one device, they then changed devices and finally made communication. But in their words, nothing pointed to anything definitive so rather than engage in some fairly expenisve swapnostics i have been doing as much as possible on the drive. The main thing they mentioned was that injector 2 was on the way out.

Once my friends fuel pump gets tested hopefully tomorrow, i can rule that and then realistically the only choices i have left is taking the fuel pipes off one by one, and giving the car in to the specialist to get the injectors changed which is a bummer. They are pretty friendly and keen to help me out, so i could probably run it by them to rig the diagnostics device they have back up, only issue is they are often booked up for about 2 weeks so getting a spot can be a bit of a ballache.

check egr not sticking

@robbie the greatl forgot to mention that in my original post, the egr is blanked off. Checked for leaks and found none.

lf the exhaust manifold has a hole or a crack in it, replace it.
You never know.

However from the video it does sound like it's going on to 4 cylinders.

Try driving it with the maf unplugged.....

lightning said:

lf the exhaust manifold has a hole or a crack in it, replace it.
You never know.

However from the video it does sound like it's going on to 4 cylinders.

Click to expand...

Hi @lightning there is a minor hole in the exhaust manifold but I've been told it's likely not this as there's no blackening around the hole and the engine sounds pretty normal (no extra loud noise coming from the hole in other words. There is a small hole after the engine block on the exhaust down by the slave cylinder but as that's after the engine completely I doubt this could be the cause of so much power loss. Although is probably a failed mot so will get the welder on that asap

craigoodwood said:

Try driving it with the maf unplugged.....

Click to expand...

@craigoodwood sadly I've tried that to no avail

Throttle wiring common fault? I had similar , write up and fix on my build thread etc

I had a similar intermittent loss of power, turned out to be the fuel pump, always started up ok and ran fine but power loss came intermittently when driving.