Disco 2 loss of power on motorway help needed parked up

Hey biggie

Thinks seemed fine in the morning and really needed to get the car away and on the road had a few appointments in Edinburgh. Plus my partner was needing back due to health issues so had to nip on.

Ordered up two harnesses and maf sensor to replace out this week.

Least the problem has been isolated to two items.

If you do suspect the harness, it is possible to clean out your old one.

Mine had been replaced before I bought the car but the red plug was not part of the harness that gets replaced, so a harness change doesnt always solve the problem (which I still maintain is not always the issue, the connectors under the rocker cover are soaked in oil with no apparent ill effects)

So I cleaned mine out with contact cleaner, you can use Jizer but I use contact cleaner for work stuff, spray into the plug, leave for a few mins then, ideally with an Aquavac, suck the residue out of the plug, I did this a few times until no more oil residue was present. You must be careful though as the vapour could be flammable.

MAF can also be cleaned with a non residue degreaser, the MAF is a thermal mass sensor which relies on a clean/dry air flow to work properly, they tend to over-read if they see a moist flow.

Yeah like I've read all over the place sometimes the red plug isn't soaking in oil but still issues can happen.

My uncle was telling me the disco's were recalled with this harness issue.

If my problem is intermittent and seems to past after a few minutes parked up. I would suspect now the harness after seeing injector fault codes.

Cause it drives like its miss firing and under feeling driving off cylinder.

So let's hope that will work. I could always once home clean up the harness and maf to get a temp fix

Probably grasping at straws. Just had another browse through the LR manual, may be worth checking the ECT Engine Coolant Temperature sensor. It may be the cause of it starting but then running badly as it warms up. But it should bring up the engine check light if its failed, could be a bad connection.

My cousin owned the car before me and funny you say that.

When asking if he had experienced this issue, he said he had once when the coolant clearly was leaking a little and enough to push it under the minimum, pipe running to top of radiator.

So I checked this pipe and weren't leaking there. Did notice the level was slightly down, so topped up. The cabin pushes out hot air and doesn't go cold.

But back to him, he said no warning light came on for him. But your right in thinking why would the car preform ok when it's cooled down, but once it's getting hot it shuts the power off.

Where is the ect located???

I just got home an hour ago with car. Been out now to have a better look around.

So took the turbo hose running to maf off to look inside, a little oil nothing major in the hose. The maf looks clean from both sides. Still if fault code is showing more likely the sensor.

Open up air filter, the filter looks ok ish. The fins all even apart from a section which was spread widely apart. But no tears on the paper.

Slight collection of water in the base.

Checked over all hoses for air. No breaks.

Was thinking could the egr be playing up??

Then I read another sensor maybe correct me aat. The ambient sender on the manifold.

The TD5 manual is actually for the Defender but assuming its in the same place, it should be "on the coolant outlet elbow on top of the engine" Its on the left side of the engine when viewed from the rear, or the right when your looking at it with the bonnet open! Hope that helps, lots of pics if you google it.

Sound marko.

I meant to say before aap ambient air pressure sensor read others say it carbs up.

Worth going the whole hog and replacing that also and doing an egr delete kit, with the injector loom and new maf.

ps, make sure the MAF connector plug is clean, again small things can trip up fault diagnostics

The AAP sensor seems to have less of a dramatic effect on performance, limits turbo boost, more effects from higher altitude, as others have said, disconnecting it sometimes makes the engine run better!

Well after work tomorrow will get some cleaner and go around the sensors and clean up plugs and the faces.

Guessing it's going to be something so simple whilst at the moment could be a number of things.

Here's hoping.

Consider the effects of each sensor. The AAP, if it was blocked, would be blocked all the time, so its signal output to the ECM (engine brain) would be "bad" all the time. What we seem to be looking for is a sensor thats affected by the engine warming up. So its unlikely to be the MAF. Apart from the ECT, the other sensor is the Fuel Temperature sensor.

Good luck, try just cleaning/checking one thing at a time then testing, its a bit laborious but it will lead you to the actual fault.

Got to hit the sack now, Im 2 hours ahead of you here!

Mark

Good thinking there. Ect and ftp.

Thanks for all your help.

Will post findings tomorrow.

Would any carb cleaner and contact cleaner do the job?? Or anyone got a certain brand that does the job better

Ive used contact cleaner, but ideally you want something that wont leave a residue.

WD40 works but Jizer, not Gunk, seems to be better.

Or Isopropyl alcohol spray

Aerosol brake & clutch cleaner is what I use - cheap and readily available. I get mine from here :

Toolstation: Brake Cleaner 400ml

Cleans really well and leaves no residue.


Dave

Injector harness has arrived this morning. Shame I'm working so be a dark cold night to fit it.

Then run it up to my uncles to plug it in and check codes.

Here's hoping

Injector harness fitted driven to uncles to check and clear codes.

Now drive it for a few days and see what comes up when retested.

Drummer87 said:

Injector harness fitted driven to uncles to check and clear codes.

Now drive it for a few days and see what comes up when retested.

Click to expand...

is it running now,any better than before?

It's running that's a good thing so far. Just abit nervous how far to push her distance wise from home.

few things noted when changing the harness. The double o ring had pitted and was flush to the plug compared to the new one that was bulging out.

The connector joining the harness cable had started to collect oil. Even though checking the red plug at the ecu end like most say was dry. The top part from the ecu had oil, so cleaned that off also