nt83

New Member
I thought that I would write this story of a breakdown in case it helps someone

Discovery Td5 2003 facelift model, manual, 15p engine (relatively recent head fix), No EGR, No Cat, First stage remap, 110,000miles - otherwise fairly standard. Owned for 5 years but used only rarely (1-2 time per month). Kept outside.

After working without problems for sometime, the engine would burp a few times (<5 times) during the first 5-10 minutes of driving (i.e. presumably from cold). It would lose power for less than a second and then run fine again. Annoying but I could carry on with the journey and so didn’t do anything about it. Never burped again after the engine was warm.


In early Dec 2019, used it on a three day holiday, First two days (4-5 hours of driving each day), the burp was as usual - a few times in the first 10 minutes and then nothing for the rest of the day.

Third day, the “burping” was more frequent and for slightly longer. Still for the same duration (maybe 1-2 secs). I drove for about three hours and it burped relatively frequently (every ~10 mins but irregular) but didn’t cause any grief (fortunately didn’t stop at junctions etc). I hoped that it would last until I got home later that day.

On dual carriageway and at 50-60 mph, it finally gave up and the power just died (engine still ran but didn’t respond to the throttle). The engine check light came on. It would restart and would idle fine but as soon as I used the throttle (and put it in gear) the power would die and the check engine light would come back on.

It was trailered back home on RAC flatbed. After a few days, I tried it again and the same problem. It would start well and idle well. It would rev well in neutral. As soon as I put it in first gear to drive it forward, the engine would just return to idle speeds (~800rpm) and have no power. I would say that it would be in limp home mode (but I have read that manuals don’t have a limp home mode). And indeed, the vehicle didn’t have any power and so couldn’t limp home at all. A very shallow up gradient was too much for it. Got it into my garage as it was down hill.

After reading forum entries, I came up with the following list of things to look at. More or less in order of time invested/difficulty/effort. I didn’t have access to a diagnostic system until I could drive it somewhere.

1. check Oil in harness
2. check MAF
3. change fuel filter
4. check (and perhaps replace) fuel pump
5. change crank position sensor

I ended up doing two things to fix it.

First - I checked the oil harness at the exit from the rocker cover (easier than taking rocker cover off). No oil. I assumed that this meant that I didn’t have a oil problem but, for no particular reason, thought that I ought to check the actual lead where it enters the ECU/ECM. Never did this before but wanted to check that there was no oil. After disconnecting the negative terminal, I unhooked the leads int the ECU. No oil. Reconnected the leads. It was disconnected for about 10-15 minutes.

The vehicle started fine and the power was back. Took it for a test drive and it was working fine. Still a little burp but otherwise back in business

Second - changed the fuel filter. Someone suggested that it as it has been sitting around for a long time, the fuel filter might need cleaning (although had been using good fuel and had not use it much since changed a few years ago (2-3000m per year)). This solved the problem of the burping. Have used it now ~5 times and it has been fine since.

Checked it on the computer and the only fault is a throttle. I have always thought that the throttle was a bit iffy but didn’t know what was normal. I will change this shortly but it seems as if the problem has gone away, at least for now.

Still no idea what happened but thought that I would share this experience with the forum.

Advice - Depending on the symptoms, of course, consider just disconnecting the ECU for a minute or two (disconnect the negative terminal first). No idea what happened but it worked for me. It might have been because I haven’t used it often and it has been very damp for the last couple of months (now Dec 2019). I have read lots of advice on solving Td5 problems and I have never seen this as a suggestion. It is easy and quick and you don’t have much to lose. I took the ECU/ECM out but maybe you just have to disconnect the negative terminal from the battery and go have a cup of tea for some of these problems!

Priming fuel filter suggestion - when trying to get the engine started after changing the fuel filter, try pumping the throttle a few times (even holding it down at maximum when you turn the ignition). I primed it about 3-4 times (turned on ignition and pumped throttle 5 times) and it wouldn’t start (the fuel pump was working). It eventually started when I floored the throttle when turning the ignition. You need a good battery though as it did require about 30-45 secs of ignition on.

Hope that this helps someone somewhere.
 

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