Engine Cutting Out

[sjane]

Hello all, just have a frustrating intermittent fault with a '91 3.5L V8i, dual fuel. Symptoms are like this:

Drive for 30 minutes with no problem.
Then occasional stumble as though key has been turned off momentarily.
Occasional stumbles get longer until engine stays off. It is not a misfire, just a hard cut to engine power. Other electricals keep operating such as head lights, radio, even tacho continues to show correct engine RPM while coasting. After a few minutes the engine can be restarted and runs perfectly. All happens the same whether running on lpg or petrol. During the stumble I notice the LEDs on the lpg gauge/selector go out, and then only when they come back on can the engine be restarted. A click is heard which sounds like the gas solenoid.
My thoughts:
Prob not ignition coil/leads as this would also kill tacho, and result in a lot of backfiring?
Prob not ignition switch as lights, radio, tacho would also go out?
Could it be the inertia cut-off switch? Engine has died once while stationary which makes me think probably not.

Any ideas? I'm really not sure if its going to get me home from work or not! :(

Cheers,
Scott.

[Scouse]

If it's the same on both fuels, then I would suspect an ignition problem somewhere.

The module on the distributor can become affected by heat. Do you have spark at the time when the engine won't start?

BTW, the tacho runs off the alternator, not the coil so that might explain why that seems OK.

[Boxer]

Mine did that, ended up apparently being a factory immobiliser issue

[Blknight.aus]

coil packs, amplifier or the imobiliser cooknig.

[LandyAndy]

I had a very similar problem on my last Series Landy.Turned out to be a faulty solenoid on the LPG system.Once replaced it never happened again,it too effected BOTH petrol and LPG use.
Goodluck
Andrew

[Scouse]

Mine did that, ended up apparently being a factory immobiliser issueHe's safe with a '91 then ;).



coil packs, amplifier or the imobiliser cooknig.Coil pack?
On a D1?

[SPROVER]

Thre are no coil packs on a 91 Disco.My guess would be the module on the distributor like Scouse said.Had this happen on a Rover SD1 V8 and it did exactly the same thing as yours.

[SPROVER]

Just read the rest of your post.After driving 30 min it cuts off.I would definately say your module on the distributor.After it gets hot it doesnt want to work and then after you let it rest and cool down it starts straight away.Although i have been wrong.:D:D

[Blknight.aus]

He's safe with a '91 then ;).


Coil pack?
On a D1?

ummm would you believe

"it was a typo it was ment to be amplifyer/coil pack..."?

no, thought not...

ahhh

"it was a test, I wanted to see who was paying attention"?.

not that either huh.

I know....

"I was covering my bases incase hed done some really cool mods."

oh alright... you got me.

I was in a hurry and didnt read all of the post so just grabbed the first 3 most likely items that can be made to fault with age and heat soaking.....



actualy if its anything like the first D1 I was involved with it could just be the earth on the coil itself... that took me a month to find and fix properly.

[Scouse]

actualy if its anything like the first D1 I was involved with it could just be the earth on the coil itself... that took me a month to find and fix properly.Hey Dave, you better stop now I think.

Since when have coils been earthed?
:p:p

It's OK, I know what you mean ;).

[sjane]

Thanks all for your feedback. I cleaned the contacts on the coil, and symptoms are gone, however one short drive is not really proof! I'll see how it goes and let you know. May need to dig deeper. Distributor module does make sense.

I hate intermittent faults!

Cheers.

[steveG]

Would a can of that "freeze spray" stuff assist with troubleshooting a heat-affected module, or is it bad to submit them to thermal shock like that?

SteveG

[sjane]

I had a very similar problem on my last Series Landy.Turned out to be a faulty solenoid on the LPG system.Once replaced it never happened again,it too effected BOTH petrol and LPG use.
Goodluck
Andrew

Andrew,
Was this intermittent/random? How did you confirm that was the culprit? Trying to avoid buying replacement parts un necessarily!
Cheers,
Scott

[sjane]

Just read the rest of your post.After driving 30 min it cuts off.I would definately say your module on the distributor.After it gets hot it doesnt want to work and then after you let it rest and cool down it starts straight away.Although i have been wrong.:D:D

Do you know if there is a way to test this? I think I'd need to buy the whole distributor as the module is integrated.
Thanks,
Scott.

[AussieLandRover]

I would be looking at the LPG side of things if you say you can see the LED's go out during the fault.

[sjane]

Today I had plenty of opportunities to further explore this fault. After performing flawlessly in yesterdays 35C+ heat, with AC on etc I was leaning away from something temperature related. However today was a disaster. About every 5km I had to give the disco a 'rest'. 5-10min was enough to get me another few km until I eventually made it home. The distance between 'rests' is definately getting shorter.

Therefore, combined with the fact that it cuts out just as often whether stationary, driving on smooth roads, or driving on rough gravel roads, I can pretty much rule out a simple loose/dirty wire or connection.

I paid some more attention to the LED's for the LPG, and noticed that they actually stay on for about 2 seconds after the engine looses power, which makes me wonder if that is in response to the real root cause, rather than directly related. Also had a LOT of backfiring today, which actually proved to be a lot more effective than the flashing hazard lights in getting people to go around. :p

So, given that ignition seems to cut first, followed shortly after by fuel, I'm leaning back towards the ignition module as the culprit. Roverparts have a replacement for $66 so I think its worth a shot unless anyone knows of a better alternative?

Cheers,
Scott.

[Scouse]

The $66 option sounds reasonable IMO.
Make sure you use silicon grease under the module (it usually comes with it).

[sjane]

Replaced HT leads, plugs and relocated & replaced ignition module, which now sits over near the coil with an aluminium heatsink on it, rather than directly on the dizzy.

Thanks all for you help.