Thread: Discovery Electrical drama, please help

It's worth buying good quality HT leads for your Disco. I've got good leads on my RR which were on it when I bought it 185,000km ago!

Spend a bit extra, get better performance, greater reliability & longer life. It works out much cheaper.

Hi All,

"Running like a Dog"> It will run fine for a couple of days then for no apparent reason it will start/seem to mis-fire and sometimes stall at the lights.

Well just had the all the intake apart to have a look and clean up while I wait till tomorrow for the HT leads dizzy cap and rotor button to come in.
I checked also the TPS sensor and bypass valve, which both seem to function correctly. I base this off experience with Detroit 60 series and Caterpillar ECM systems which is part of my background. Very different to Petrol EFi but principles are similar.
I also found something very interesting with the Alternator, that may be the cause of my woes. The Alternator seems to drop charge now and again when driving and the engine is at operating temp. Not really knowing the system too well and the Haynes manual being as much use as a chocolate tea pot for diagnostic purposes. I wonder if this has anything to do with the engine breaking down, the alt iis with the auto sparkies now for them to slap on the test bench and put it through it's paces. Will see what effect it has after rebuild as I'm sure it is fingered.

will keep you posted. Oh......it's an auto tranny too !

Cheers

Haggis.

Oooops.... I thought we were talking about the 200TDi. ops:

Now that I've caught up.... I've had a similar problem in the past on a V8. Had it on a dyno, got it all checked out & everything was OK. When you got it on the road, it was as rough as a badgers @rse to the point where I thought it was a blown head gasket.

A new set of HT leads cured it. For some reason, the Rover V8 is very fussy about the quality of HT leads. :?

However, just check for excessive pressure in the cooling system and loss of coolant just to be on the safe side.

Mark.

i was just about to mention the alternator.......these cause all sorts of electrical problems and almost all of them intermitent.

always behaves when being tested or run by the repairer...then when the car is given back to the owner all sorts of problems start again.

the throttle position sensor mentioned can easily be tested with multimeters.
just unplug it and connect the meters and check the resistance....have someone SLOWLY press the accelerator to the floor and check that you have a smooth consistent reading all the way through and back....if the reading cuts out or jumps around the TPS is worn and will need to be replaced.

i was just about to mention the alternator.......these cause all sorts of electrical problems and almost all of them intermitent.

always behaves when being tested or run by the repairer...then when the car is given back to the owner all sorts of problems start again.

the throttle position sensor mentioned can easily be tested with multimeters.
just unplug it and connect the meters and check the resistance....have someone SLOWLY press the accelerator to the floor and check that you have a smooth consistent reading all the way through and back....if the reading cuts out or jumps around the TPS is worn and will need to be replaced.

Originally posted by DEFENDERZOOK
i was just about to mention the alternator.......these cause all sorts of electrical problems and almost all of them intermitent.

always behaves when being tested or run by the repairer...then when the car is given back to the owner all sorts of problems start again.

Mind you, if it's under charging the warning light should come on... If it's over (i.e. the regulator is fried) then you'll be blowing bulbs on a very regular basis.

If the dash light has blown, the alternator won't be charging at all. So, if the battery condition is bad enough for the engine to start running rough, you probably wouldn't have enough charge in the battery to start her in the first place.

Mark.

some times they surge...so no lights no warnings no nothing...just problems which cannot be found.

i have seen all sorts of sensors and computers changed on cars all to no avail.....then as soon as the alternator is changed it all settles down straight away.....go figure.

Originally posted by DEFENDERZOOK
some times they surge...so no lights no warnings no nothing...just problems which cannot be found.

That's what I meant by the overcharging & fried regulator, I had that on one of my RaRos. When driving at night I could suddenly see everything as light as day before the bulbs blew :!: :?

Mark.