Disco 2 TD5 Stalled in Traffic

My vehicle is a 1999 Discovery 2 TD5, with a newly rebuilt engine and lots of other work done to it.

Drove around town all day yesterday, several stops, then on the way home, with lots of sitting in hot traffic (I’m in Kampala, Uganda), vehicle threw the CEL for a split second, ran rough for another split second and then conked out. This on a an uphill, narrow street that was jammed already. Lovely experience blocking heavy traffic at rush hour. Bunch of guys finally came and pushed me up the hill (tough job) and off to a side area where I sat for a while.

Engine would start immediately after stalling, as if nothing was wrong, but would simply conk out again with a flash of the CEL if I tried to go. For fun, I tried keeping it in idle—no issues. Then I revved it a little in neutral—conked out.

After allowing everything to cool down for thirty minutes, I started it up and was able to drive home, keeping RPMs under 2,000 just in case. But no issues. And once home, I ran up the RPMs in neutral and there were no issues. Then later that night had to take it out to meet someone and no issues going there and coming back.

Scary problem to have, being so unexpected.

Lots of smoke by the way, quite regularly, especially on startup, and the mechanics claim it just needs broken in... but I’ve driven it about a thousand kilometers and it hasn’t changed.

Also, it has the “trouble with cold starting when tank is around 1/4 full,” though I doubt these two are related, from what I’ve read.

My top thoughts are:
1. Injector seals (replaced in last two years with Britparts)
2. CPS

Any suggestions?

One other symptom I just remembered that was strange:
After stalling each time, the engine would continue to shake as if something was still going, and it wouldn’t stop until I turned the ignition off.

Can be many things, CPS included but do this test cos the pump is suspect too : https://www.landyzone.co.uk/land-rover/check-td5-fuel-pump-hp.358086/

Thanks, superb write-up sierrafery.

I’m getting 18.8 reading of the fuel pump fuse on engine start-up, dropping to 17.7 gradually after it warms up. Pump was changed about five years ago, according to the mechanics.

You really need to plug in a compatible diagnostic tool cos the EML should have left a code stored in the ECM.

Yes, have my mechanics coming tomorrow to plug in their Lynx. We’ll see what it says...

ISTR that only two things will throw up the MIL (CEL) on a manual - crank position sensor and the throttle position sensor. You may have a fuelling issue, but I would guess that one of those two is what caused the problem. Get a diagnostic on it and read the DTCs - my money is on a Crank Sensor High fault (Crank Sensor Low would prevent it starting).

Mechanic finally came, and the MAF was reading 0.03v. The inside of the air intake tube around the sensor was coated in oil. Mechanic claims the backflow of oil through the breather tube (which appears to have killed the MAF) is due to a piston ring not sealing correctly, due to a recent couple of overheats that occurred after coolant hoses burst—he thinks driving it on the highway should help “unstick” the piston ring and eliminate the oil backflow.

Any sense in this?

Also, there was a Crank Sensor High code historically logged, can’t remember what the number was, but he didn’t seem concerned about it.

Find other mechanic cos the crank sensor fault code is very important as it can be the gist of your problem, the connector or wiring to the CPS are common failures and the sensor can make tricks as well so you should concentrate on that as your vehicle stalled in traffic which can't be due to MAF or a piston ring whatsoever but it can be due to CPS input failure that's why these kits are well sold https://www.ebay.co.uk/itm/251316693883

Your mechanic knows nothing about TD5 engines. Assuming the engine is original you have a 10p version of the TD5 which makes little use of the MAF sensor. Even if you had a 15p engine which does use the MAF for fuelling data, the engine would use a default setting and carry on running, albeit less efficiently.
A high fault on the Crank Position Sensor on the other hand will cause the engine to stop in the way you describe. Which is why I speculated that this could be the cause on response #7.
If you can access the wiring loom, then the kit sierrafery shows should fix the problem. However access is really tricky and you might find it easier to replace the sensor wiring in its entirety, wiring the new shielded cable into the red ECU plug.

Fantastic bit of knowledge, thank you guys for sharing! Makes sense to me, the MAF killing it like that seemed strange but I deferred my judgment. The MAF is dead nevertheless so replacing that might help with some low powering issues, right?

I am taking the Rover to the mechanic’s shop today to have all coolant hoses replaced with silicone hoses (have had two rubber hoses bursts in the last month and cause two overheats; this on a just-rebuilt-engine). I’ll have them pull the CPS sensor and see if we can fix it. Everything takes 3 weeks to get here from the UK by air (I’m in Uganda), so hopefully we can just repair the existing multiplug. I have a slew of electrical tools, wiring and components, I’ve been rewiring a few things in the rover and setting up a solar system here so maybe I can manage to repair the wires with what I have... we’ll see.

I’ll report back with an update. Thanks again!

The update is that the crankshaft sensor and multiplug and wires are completely soaked in fresh oil, and the path is clearly from the engine breather hose. They’re going to clean it all up for now, we’ll see what that does. Definitely due to the engine overheats.

In the meantime, I’ll be placing an order for piston rings, bearings and all that good stuff. This is going to be fun.