Engine stalls when brakes applied?

Just got a diesel leak sorted and now have another (unrelated) issue. Engine stalls when I apply the brakes. I thought electrical but now not so sure. If I apply brakes lightly and then release quickly as engine starts to stall, the engine doesn't stall. When this happened previously, I disconnected the electric connection and loosened the lid of the brake fluid reservoir, seemed to release some air - disco ran fine. Not this time though! I found a similar issue posted in 2019, referenced a short at the brake pedal from the ignition wire - sounds like my issue possibly but not followed up on thread. Any ideas, could do with getting the old girl going as we are experiencing some pretty bad flooding here in Co Down right now. Thanks in advance.

Unplug the brake pedal switch and test it so... if it's OK that way we'll speak then

Is your servo full of brake fluid ? I seem to remember a 200 tdi I owned doing something similar

sierrafery said:

Unplug the brake pedal switch and test it so... if it's OK that way we'll speak then

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Thanks sierrafery, just checked the brake pedal switch, it was loose, gave it a half turn to re-bed and presto issue resolved! Hopefully that's is sorted. Another piece of useful Disco knowledge and experience now banked away for the future. Thank you.

It's possible that you have a fuelling issue too cos even though the brake switch's N/C contact works with the management as when the brake is depressed that contact opens and the ECU limits the fuelling but the engine is not supposed to stall only to lose some power, explained here(unfortunately the pics are lost) https://www.landyzone.co.uk/land-rover/jerks-in-lower-gears-transmission-shunt.184831/post-1949274

so check this out out: https://www.landyzone.co.uk/land-rover/check-td5-fuel-pump-hp.358086/

sierrafery said:

It's possible that you have a fuelling issue too cos even though the brake switch's N/C contact works with the management as when the brake is depressed that contact opens and the ECU limits the fuelling but the engine is not supposed to stall only to lose some power, explained here(unfortunately the pics are lost) https://www.landyzone.co.uk/land-rover/jerks-in-lower-gears-transmission-shunt.184831/post-1949274

so check this out out: https://www.landyzone.co.uk/land-rover/check-td5-fuel-pump-hp.358086/

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Very helpful, no kangarooing, engine running fine, very smooth and no dash lights. Will keep an eye out of course. Thanks again. G

Seems that you didnt understand my point, if everything is OK with the fuelling and it's about the brake switch it happens eventually what i described but it shouldn't stall whatsoever

Ok, you’re going to have to help me some more to understand properly. Disco, lost all power yesterday while driving at 50mph. Luckily I was able to coast to a side road safely! Tried wriggling the brake pedal switch again and disco started, though when pedal pressed it stalled again. Had to get disco recovered as I and AA guy could not get it started. Was towed to an AutoSpark - hoping they can sort - closed until tomorrow. Guessing they will need a steer. The link you shared suggests pedal switch needs to be reset - could that be the source of my issue? Car runs and drives fine when started. Nightmare lovely start to the new year - had a days fly fishing planned with my dad -

The brake switch needs to be reset only if it's certain that it's not faulty and the plunger is not reaching the pedal but as i said at least twice untill now the engine is not supposed to stall if that's the only fault so as long as you keep ignoring what i said in post #5 and you dont confirm that the fuel HP is OK i have nothing more to say.

sierrafery said:

The brake switch needs to be reset only if it's certain that it's not faulty and the plunger is not reaching the pedal but as i said at least twice untill now the engine is not supposed to stall if that's the only fault so as long as you keep ignoring what i said in post #5 and you dont confirm that the fuel HP is OK i have nothing more to say.

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Ok, though I can’t now conduct your test as disco will no longer start. In-tank pump was replaced about 2 years ago and I recently replaced one of the small yellow o-rings inside the pump (green line) Pump is priming and working well, no starting, stalling or spluttering issues, runs extremely smoothly when started. Some pics of my recent repair attached. I salvaged 3 good O-rings from a scrapped pump.

For that test it's enough to have ignition on 2 and hear the pump running... the pump runs normally on LP and in some cases the engine is running too but not at full power, the only way to see if it has HP is with that test or with a gauge in the FPR... i'm saying for the last time that a brake switch fault can reduce power but it should still start and run so there must be another issue too beside that... if you worked inside the pump the best would be to measure the fuel pressure with a gauge cos even if it passes the mV test there can be some pressure loss in it. You should replace and adjust well a new brake switch anyway to be 100% ruled out

Thank you. No power to pump or to dash lights either. All
Lights in the dash are out. Power to clock and radio but no instrument lights come on when key is in position 2 l.

GPHDISCO2 said:

No power to pump or to dash lights either. All
Lights in the dash are out

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That's a totally different story then, you should have said that clearely from the beginning...in this case it's an electrical fault which needs investigation, earths are suspects but it can be bad contact in the fusebox too or in the worst case a chafed wiring somewhere... there is a header under the carpet which delivers earth to the dash and fusebox check that first to not be corroded as things happened when you played with the brake switch in that area (C0551)

Apologies for lack of clarity at out set. Source of issue was indeed a bad earth connection. AutoSpark sorted very quickly, ready for collection today. Thank you again for taking the time to respond, top man

G