Cutting out

[Merlin]

My sons 91 3.9 efi Classic auto keeps cutting out completely for no reasen.  It was OK till this week & started doing it for it's own reasons.
When it cuts out the side lights still work but not the headlights, the hazards but not the indicators (luckily).  This is very dangerous as he does motorway driving.
I cannot give any other pointers as to the problem but he will be on line late tonight/early morning when he finishes work (thats if he can get home) so can you think about what it can be & put some idea's on for him.
My only idea is that it must somehow be caused by an ignition fault but there may be some "recognisable" problem that someone has had themselves.--Cheers--Merlin

[Garth]

Cheers Cogs

Here is a bit more detail

My RRC 1991 3.9 efi  started stopping a couple of days ago. I was driving along and with out warning the engine stopped, headlights went to sidelights, I had no indicators and no ignition lights, but hazards worked OK.  I pulled over and tried to restart the starter turned over but again no igtnition lights and no fireing at engine.

Its as if the supply to the ignition supply has failed.  I have removed and reinserted fuses and makes no difference.  I have to wait between 30 to 180 seconds then the ignition lights come back on and the engine will start.

Today this happened 4 times on the way to work and 6 times on the way home so its getting worse, (its approx 5 miles from work to home).


Any help would be greatly recieved


Many Thanks

Dave (Garth)

[dazzawhipple]

It could be the ignition barrel .......replace that first

I had a car that kept doing somthing like what you have described found that the earthing strap was loose in the terminal only discconected when braking.

[TimM]

It definately sounds ignition related, due to the circuits that are working or not working when it happens.

If you are lucky it will be some loose wiring, have a route around and see what you can find, could be at the ignition or possibly at the fuse box end.

You haven't done anything with the electrics recently have you - spots, CB, anything - even changed a fuse!, I'm just wondering if something has become disturbed and has broken a circuit.

[thermidorthelobster]

I'm no electrical genius, but that sort of thing always seems to ring "earthing fault" alarm bells...  Great fun to resolve!

[Landy90IOM]

ive heard of this kind of problem before, and it turned out to be the ECM.  could be worth having a look into that too if all else fails

[Budgie]

Just a thought but, does it have an immobiliser fitted?

Could be faulty and arming itself?
Although you normally get ignition lights with one of those, even when armed.  :-k

[The Fat Controller]

as THERMODORTHELOBSTER said "it sounds like an earth problem" and you will probably find its the earth stap from the battery where it bolts to the chassis down by the steering box,the easyest way to prove it is to use a "jump lead" from the battery negative teminal to the engine as a temporary earth,if the car them starts and lights work you have proved an earth fault exists.the cure is a new earth strap with a new bolt through a clean chassis

[forkarm]

hiya, i had one last month with a similar problem.i traced the problem down to the fuse links in the wiring harness.if you follow the harness out of the bulkhead toward the battery you will notice a bulge in the harness with a braided sheath.slit this open and give the wires inside a good tug.with a bit of luck one (or two ) will come apart and you will see the corrosion on the ends of the wires.hope this helps.

[Garth]

Thanks for the advice folks however the gold star goes to Budgie!! (I think).

Went out today and drove around aimlessly with everything electric on and off on and off till found I could make it cut out switching main beam on and off. Leave for a few minutes and ingnition lights came back on. Away we went.  Did this several times just to make sure.

Drove home and stared at the Haynes wiring diagrams for an hour.

In I went , column shroud and footwell plastic removed, checked ignition switch = 12 volts where it should be.  So left ticking over with everyting switched on switching from main to dipped continuusly and it stopped, dived in with multimeter and 12 volts at ignition switch (swear words were issued).

Back to manual!!  (You need wiring digram to follow the next bit).
No voltage at tacho
No Voltage at Headlamp relay
No ABS Lamp
ETC ETC

SO traced ignition on wire back (the big white one) and found (to cut a long story short) that it was wired via the alarm/imobiliser ran a new wire in parrallel with alarm with an inline 10 amp fuse and power was restored.  HURRAY.

Left on tick over switched a few things on and OK.

Went for main beam and my inline fuse blew. BOO

Put a 30 amp fuse in and took out for a run as above and so far everthing appears OK but my inline fuse is getting hot (but not blowing).

QUESTION.

I have a multimeter. How do I measure and what current should I expect on this wire (it is approx 2.5 mm).  

From previous comments I dont think my alarm/imobilser should have been wired in this way.

I hope this makes sence to someone

Garth

[Budgie]

Thanks for the advice folks however the gold star goes to Budgie!! (I think).

 \:D/  \:D/  :mrgreen:


Sorry, just showing off!!  

I hope that's it then Garth, although I don't like the sound of the 30 amp fuse getting hot!  :-k Sounds like you may have more investigation to do.
I think the rating for 2.5mm cable is about 25-30 Amps can't remember exactly off the top of my head.

[Garth]

Well all has been well since I ran in temp cable.  The fuse has never got really hot or blown so I think its time for a permanent repair and removal of NG alarm/imobiliser.  

Thanks again

Garth