Cutting Out issue. An Ignition or Immobiliser issue?

[ChasR]

Since I can remember my Stag has a strange cutting out issue. Initially I thought it was the Newtronic system but after today I am not so sure.

Basically when going along (it seems to do this more at idle, although it did once happen to me doing just over 70MPH on the M40 ) the car will just die. The ignition lights and gauges all go out although items not powered by the ignition (I.e the headlights) still stay on. After around 5 seconds the IGN light and gauges will come back to life along with a click of the relays from the relay board, with the car firing up straight away on demand.

This time however, when the IGN light came on, it also quickly went back out again only to come back on again within a second. The other strange part is that it seems to cut out after 20-30 minutes of the car being fired up and running.

The car does have an immobiliser (a T.H.E Immobiliser with a plug in key: Anyone familiar with these old tech immobliser?), which I now also suspect (It seems to cut off the starter feed and ignition feed when the push in key is not in place in the socket, although it does not affect the operation of the IGN and other lights in the round cluster).

Changing the carbs (although that was done for other reasons), a replacement coil and ignition components (rotor arm for a red type, spark plugs (NGK BP5ES), and leads) seem to have made no difference although I suspect it is more of an issue with an ignition component (switch maybe?) or the loom itself.

Whilst I suspect it may be a duff connection somewhere (I intially had to solder many a chocolate block out of the loom so as to make the car a reliable runner) have you chaps had this issues before, and if so, what caused it?

Cheers, and fire away .

[Staggard]

Since I can remember my Stag has a strange cutting out issue. Initially I thought it was the Newtronic system but after today I am not so sure.

Basically when going along (it seems to do this more at idle, although it did once happen to me doing just over 70MPH on the M40 ) the car will just die. The ignition lights and gauges all go out although items not powered by the ignition (I.e the headlights) still stay on. After around 5 seconds the IGN light and gauges will come back to life along with a click of the relays from the relay board, with the car firing up straight away on demand.

This time however, when the IGN light came on, it also quickly went back out again only to come back on again within a second. The other strange part is that it seems to cut out after 20-30 minutes of the car being fired up and running.

The car does have an immobiliser (a T.H.E Immobiliser with a plug in key: Anyone familiar with these old tech immobliser?), which I now also suspect (It seems to cut off the starter feed and ignition feed when the push in key is not in place in the socket, although it does not affect the operation of the IGN and other lights in the round cluster).

Changing the carbs (although that was done for other reasons), a replacement coil and ignition components (rotor arm for a red type, spark plugs (NGK BP5ES), and leads) seem to have made no difference although I suspect it is more of an issue with an ignition component (switch maybe?) or the loom itself.

Whilst I suspect it may be a duff connection somewhere (I intially had to solder many a chocolate block out of the loom so as to make the car a reliable runner) have you chaps had this issues before, and if so, what caused it?

Cheers, and fire away .

So if I have read this right it sounds like a ignition switch or a feed issue if you hot wire it (a live from the +side of the battery to the coil) and see if you still have the problem. Graham

[wilf]

+1 on the ignition switch. Not to difficult to bridge it to check as Staggard suggests.

[Staggard]

sorry just realised m2 if you hot wire it from the battery you a resister 6volt coil .Graham

[ChasR]

Cheers for the suggestions chaps . I guess if I was to directly wire a feed to the coil from the battery it would be a good idea to do the test with a ballast resistor in the way? Or would this not be an issue (IIRC the ballast wire is in the negative feed is it not?).

However, it seems after talking with a few alarm friends of mine that the immobiliser of mine was not particularly clever even when new! It's apparently over 20 years old and has the power of the ignition going through the immobiliser key.

[V Mad]

Cheers for the suggestions chaps . I guess if I was to directly wire a feed to the coil from the battery it would be a good idea to do the test with a ballast resistor in the way? Or would this not be an issue (IIRC the ballast wire is in the negative feed is it not?).

Ballast is in the positive feed. You can test run the coil directly from battery but only for a short while or it will overheat.

[wilf]

Unless you really want that immobiliser, I would strip it out.

[Staggard]

Ballast is in the positive feed. You can test run the coil directly from battery but only for a short while or it will overheat.

"The other strange part is that it seems to cut out after 20-30 minutes of the car being fired up and running"

If this the case I would not reccommend running 12volt to 6volt coil without a resistor UNLESS your AA membership is fully paid up OR you like walking I also agree with Wilf ditch the immobiliser and fit a decent alarm or fit a secret switch (but rember don't tell us where it is ) there's a few shady character's about Graham

[ChasR]

I did wonder that (it really is an intermittent issue). I guess an alternative method would be to put a ballast resistor from a MkI into the temporary feed?

The immobiliser will come out (it seems they are not the most reliable of things) but that will have to wait until it is a little warmer outside. Quite a few of the gubbins live above the gearbox, which should make extracting it from the car just a bit of fun!

[richard w]

Since I can remember my Stag has a strange cutting out issue. Initially I thought it was the Newtronic system but after today I am not so sure.

Basically when going along (it seems to do this more at idle, although it did once happen to me doing just over 70MPH on the M40 ) the car will just die. The ignition lights and gauges all go out although items not powered by the ignition (I.e the headlights) still stay on. After around 5 seconds the IGN light and gauges will come back to life along with a click of the relays from the relay board, with the car firing up straight away on demand.

Surely you mean exactly 70mph on the M40!!

Richard

[new to this]

you said it doesnt happen all the time,so i would disconect the immobiliser first,then see if the fault is still there,then your know if it is a ignition or immobiliser fault

dave

[ChasR]

Speedo 'over' 70 . I was going off the GPS. No, wait, I can only go off the GPS for now...

[keeny]

If its a plug in type is quite old? ,they were very temperamental when only 6 months old.i had several develope falts as you describe when the car has been running for 20 minutes or more ,on previous cars(they get hot from the currant running through them then break down) by pass it as its the most likely cause of your problems
Keeny

[keeny]

P.s did this fault start after the electric ignition was fitted as the old style immobilliser seemed to struggle with the power running through it

[ChasR]

I couldn't answer the last question Keeny since it came with the immobiliser and ignition system when I bought it . It is indeed the plug in type, and as you say, many reckon (especially those in the industry from years ago) that they are more trouble than they are worth.

Removing the system is definitely on the cards, but I shall wait for the snow to melt first . Hmmm, 14^oC next week? We shall have to see..