Intermittent cutting out problem

[Sharpy]

My S3 has recently developed a frustrating intermittent cutting out problem. It has happened 3 times in the past 2 weeks now, always when the engine is not under load e.g. idling or slowing down to turn into a side road. The engine just stops, the guages drop to zero and the car won''t restart. The engine turns over normally, and the lights work but the ignition lights don''t come on, the fuel pump can''t be heard coming on, the interior heater fan doesn''t work, the electric mirrors don''t work and of course all the guages are on zero. I have noticed recently that the voltmeter has been reading lower than usual, and that with lights on the indicator is dropping to the border of the red. After about 5 minutes, even without fiddling with anything, the power will magically return, the ignition lights etc. coming on and the car starts normally! I would be very grateful for any advice from anybody who has experienced a similar problem or who can help me diagnose the problem from my description.

[johno]

Check the battery voltage across the terminals initially to see whether you are getting enough charge to the battery. Should be around 13-14 volts. The cabin voltmeter is not as accurate as a proper voltmeter. I suspect the real cause though is probably an earthing issue. Check the battery earth to chassis first, take it off clean it up and then replace covered with grease. The work your way around all the earths. There's one in the n/s front wheel arch on the chassis there and others around the engine bay. After yhis I would double check the fuse box is all secure or that no water is dripping onto it. Does this problem arise in both wet and dry conditions or just in the dry. If none of this helps then I would suspect a possibly dud battery although the previous measures cured my problem.

[GreenV8S]

The plug between the ignition switch and the loom is my favorite suspect. If you take the cowl off the steering column you can see the ignition switch itself opposite the barrel where you put the key in. Follow the wires away from the switch and after a couple of inches you'll find the multi plug. This takes quite a heavy current and doesn't really seem up to the job. You can repair it by cleaning and re-crimping the electrical contacts. Hope this helps, Peter Humphries (and a green V8S)

quote:My S3 has recently developed a frustrating intermittent cutting out problem. It has happened 3 times in the past 2 weeks now, always when the engine is not under load e.g. idling or slowing down to turn into a side road. The engine just stops, the guages drop to zero and the car won''t restart. The engine turns over normally, and the lights work but the ignition lights don''t come on, the fuel pump can''t be heard coming on, the interior heater fan doesn''t work, the electric mirrors don''t work and of course all the guages are on zero. I have noticed recently that the voltmeter has been reading lower than usual, and that with lights on the indicator is dropping to the border of the red. After about 5 minutes, even without fiddling with anything, the power will magically return, the ignition lights etc. coming on and the car starts normally! I would be very grateful for any advice from anybody who has experienced a similar problem or who can help me diagnose the problem from my description.

[Sharpy]

Thanks for the replies Johno and Pete. After much fiddling and testing I have located the problem to the live wire from the ignition barrel to the multi plug. I can now turn the engine on then make it cut out by just slightly moving this wire. Unfortunately curing this faulty connection is proving to be slightly more problematic than anticipated. I cannot for the life of me get either the multi plug apart or the spade terminals out from the plug! I think I shall have to resort to a local mechanic for help unless anybody has any suggestions? Thanks anyway for your help in locating the problem, Sharpy

[GreenV8S]

If yours is like mine on the V8S, it's a bit fiddly but easy enough once you've got the nack. First problem is to unplug the plug. There's a plastic latch to stop you doing this. The latch is a plastic strip with a hole on sticking out from one plug, which engages on a tapered plastic lug on the other half. The side with the lug on also has a couple of ridges on either side of the plastic strip. To open it, pull the plastic strip clear of the lug, then pull the two halves apart. I found the best way to do this was to lever the strip back with a small screwdriver, then jam the screwdriver between the strip and the body of the plug to stop it springing back. Then use a pair of fine-nosed pliers on the end of the flat strip, and the ends of the plastic ridge next to it, to push the two halves apart. It takes quite a bit of force but is easy enough with pliers. Once you have got the two halves of the plug apart you need to pull the connectors back out of the plug. There's a plastic 'gate' in the side of the plug which engages with the electrical contacts to stop them being pulled out. You can lever the 'gate' open with the corner of a small screwdriver, which leaves the contacts free to fall out. If the battery is connected they are live, don't let them short on anything! Hope this helps, Peter Humphries (and a green V8S)

quote:Thanks for the replies Johno and Pete. After much fiddling and testing I have located the problem to the live wire from the ignition barrel to the multi plug. I can now turn the engine on then make it cut out by just slightly moving this wire. Unfortunately curing this faulty connection is proving to be slightly more problematic than anticipated. I cannot for the life of me get either the multi plug apart or the spade terminals out from the plug! I think I shall have to resort to a local mechanic for help unless anybody has any suggestions? Thanks anyway for your help in locating the problem, Sharpy