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MG MGA - intermitent electrical problem

Help,on my 57 A I have an alarm whitch also acts as an imobiliser whitch i may (or may not) be having a problem with.
periodicly the engine will cut out for no apparent reason leaving no live feed from the coil and me sat at the side of the road looking daft(I seem to think that the emobiliser kicks in by itself)then after a short time and a bit pokeing about under the bonnet(I realy have very little idea what im pokeing)the feed returns to the coil and away we go untill the next time, does anyone hve any ideas that may help, sorry about my spelling, vin
V Rafter

Sorry, that should read NO LIVE FEED TO THE COIL
V Rafter

Most of the alarms insert the switch in series with the ignition feed to the coil. It should be an easy task to put a simple test jumper across the switch to see if that is, in fact, your problem. The PO of my car installed a switch in line with the fuel pump. I didn't know about the 'kill' switch until my wife hit a strong pot hole, and stalled out by the side of the road. The hit was hard enough to jar the switch lever to 'off'. Ouch! It took a little electrical diagnostics to find out what was going on an why.
rpb bunch

Could be a coil. One way they fail is the coil quits hot then works after cooling.
R J Brown

you say that there is no live feed to the coil, have you checked this with a digital meter or taken a spark plug out and laid it on the block to see if there is a spark?
I ask this as i had the identical problem when i first got my car, i was convinced it was an electrical fault and i went through the usual suspects. i changed the plugs, the points. the condenser, i fitted a new coil thinking that it could be overheating and breaking down when hot. I even went so far as to solder ALL the connections in the points and condenser but the car still broke down after 10 to 20 miles.
It turned out to be a some silicon sealer that had partially blocked the in-line fuel filter and if i had only checked it earlier i wouldnt have wasted 2 months of summer driving.
My thanks to Bob West and James for taking the time to find and fix the problem and for ignoring my embarassment at missing something so obvious.
I hope you get to the bottom of the problem soon.
Cheers
colyn
c firth

This thread was discussed on 27/06/2009

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