V8 Disco Runs & Dies.

[Cuprar22]

Hi,

I've got a 95 3.9 Discovery XS Man.

Start it up and it runs fine, as the engine starts getting up to temperature after a couple of minutes, it just dies and wont restart until cold. It doesn't start running rough or missing, it's just like turning the key off.

Any advise would be much appreciated.

Pete

[discool]

The Efi coolent temperature sensor, may be. It's located by the front left hand branch of the inlet maiifold.
AMR1425 sensor temperature from Vin MA081991.

[Cuprar22]

Thanks.

Trying that tomorrow.

I'll let you know if it works.

Pete

[Zohartheziggy]

Sorry, and hate to second guess. Moreover, it seems plausible that if the problem is temp-related, then look at the temp sensor.
However, in my experience, when the sensor goes bad as I had it, the engine starts running rough when hot (it would get a too-rich mixture, the faulty sensor saying it was cold), BUT NOT CUT OFF COMPLETELY. Same for the O2 lambda sensor or the MAS sensor; they would still cause lumpy running but not a cutoff. Thus, I would think of a completely unrelated problem, such as a loose connector; true, this does not relate to the observation "would start again when cold", but who knows. One such connector which is very sensitive to engine operation is the connector on the MAS: try jiggling it or open it, spray electronic connector cleaner on the leads and replug it in - not sure but at least costs nothing. Same for the stepper motor connector (at the back of the plenum chamber, a black plastic round barrel about 1" dia).
BTW to test the water temp sensor, you could unplug it when cold and see if it made any difference when running the engine from cold.
One more test to the temp sensor: you measure the resistance with any ohm-meter between its only protruding lead and the ground (engine body mass); I don't remember the resistance, but there should be a clear difference between hot a cold.

[Zohartheziggy]

MAS? MAF? (I meant the mass airflow sensor)

[Cuprar22]

Tried the ecu temp sensor.

Didn't work and will not start at all now (Even with the old one).

Trying more things tomorrow, trying to narrow it down to fuel or ignition as it's not even trying to fire now.

Thanks for the advice so far, any other suggestions greatfully accepted.

Pete

[v8jobster]

if it now doesn't start at all, get back to basics. Is a spark getting to the engine?? When did you last change plugs,leads,dizzy cap and coil?? Whats the condition of the plugs??

[Zohartheziggy]

Sure, first check the basics as V8jobster suggested, spark, fuel.
But since there so little effort involved, I still stick to my initial suggestion of checking the connector to the Mass Airflow Sensor sits tight and makes good contact. Of course a no-run condition can be caused by a number of things, but in my personal experience, I had a couple of no-runs and one was because the connector was not sitting properly, and the second, because of the connector to the fuel pump in the boot, which I discovered when I found out that no fuel was getting to the injector feed line. I hope yours has a vent like I have because I think it's not original but it's very useful to check fuel delivery; it's on the right side of the engine and looks like a regular tire valve sitting on the fuel line.
Keep us posted and good luck,
Z

[Cuprar22]

No spark now.

New dizzy going in tomorrow.

Pete

[v8jobster]

if there's no spark after changing coil and everything, then there's the amp module which is situated behind the grill next to the back of headlight, (well it is on my 94 v8i) this might be the cause. About £30 from a motor factor. Some new dizzy's have them on the side, i personally don't like that design as they're prone to heat build up there.

[Cuprar22]

I'm sticking a mallory dizzy on it, got one lying around and never had problems with them in the past.

Pete

[Cuprar22]

It Lives.

Looks like it was the dizzy. It had already had a new amp a while ago as I had one for my other one before I put the mallory on.

Now I just need to find a cheap dizzy as it's the wifes car, and I need the mallory for another engine.

Thanks for all the advise.

Pete

[v8jobster]

glad you got it sorted.

Wouldn't worry about the wife's car :D