malcolm Posted February 4, 2007 Report Share Posted February 4, 2007 I've a problem with my V8 track car. It will fire on the starter, but as soon as I release the key to 'normal' it dies. If I leave the starter engaged (obviously I've not done this for long) it runs. A electrical tester shows there is voltage across the coil when starting, but none after this. I have an old SD1 ballast resistor fitted and am thinking it is the problem? The 12v starter coil voltage being fine, but the lower (9v?) running voltage being fubar'd. Does anyone have another I could Buy or Borrow?? PLEASE? Malcolm. Quote Link to post Share on other sites
Beans Posted February 4, 2007 Report Share Posted February 4, 2007 (edited) Time for the good ol' methodical approach. Get your meter out and start at the ignition switch, that would be my prime suspect. Work from the switch "down" to the coil/ignition I had exactly the same problem with my previous LaRo Edited February 4, 2007 by Beans Quote Link to post Share on other sites
guzzitrike Posted February 4, 2007 Report Share Posted February 4, 2007 I'm no expert in electrics, as some of my posts show, but I came across a description of what a ballast resistor does. It simply boosts the voltage to initially fire up the engine using a coil of a lower voltage. Therefore should have no influence on what happens after the engine has started. The problem is more likely to be in as Beans has said in the wireing to the ignition switch side of things. I may of course be totaly wrong but sometimes it is worth standing back and not asuming. PS still trying to sort out my Tacho will post the answer up once I have discovered what the problem is. Bryan Quote Link to post Share on other sites
whiteone Posted February 4, 2007 Report Share Posted February 4, 2007 I'm no expert in electrics, as some of my posts show, but I came across a description of what a ballast resistor does. It simply boosts the voltage to initially fire up the engine using a coil of a lower voltage. Therefore should have no influence on what happens after the engine has started. The problem is more likely to be in as Beans has said in the wireing to the ignition switch side of things. I may of course be totaly wrong but sometimes it is worth standing back and not asuming. PS still trying to sort out my Tacho will post the answer up once I have discovered what the problem is. Bryan Quote Link to post Share on other sites
whiteone Posted February 4, 2007 Report Share Posted February 4, 2007 Guzzitrike, I'm not sure that your understanding of a ballast resistor system is correct. I think you will find that the resistor is part of the normal ignition system and is by-passed during cranking. This resistor is usually ceramic based and consists simply of a length of high resistance wire between 2 terminals, there are usually one or two metal lugs to enable the resistor to be bolted to the engine or chassis. A 12 volt system will have a ballast resistor which reduces the voltage available at the ignition coil to 6 volts and the ignition coil used is actually a 6 volt unit. During cranking, an additional terminal usually found on the starter solenoid or the starter motor (which is operated either by operation of the ignition switch or engagement of the starter pinion) provides a full 12 volt supply to the 6 volt coil, thus boosting the high tension voltage. On some vehicles, including I believe Ford Cortinas and Granadas a resistor cable was incorporated in the ignition wiring loom so you will not see a conventional resistor. Hope this info is correct and helpful. Quote Link to post Share on other sites
whiteone Posted February 4, 2007 Report Share Posted February 4, 2007 I've a problem with my V8 track car. It will fire on the starter, but as soon as I release the key to 'normal' it dies. If I leave the starter engaged (obviously I've not done this for long) it runs. A electrical tester shows there is voltage across the coil when starting, but none after this. I have an old SD1 ballast resistor fitted and am thinking it is the problem? The 12v starter coil voltage being fine, but the lower (9v?) running voltage being fubar'd. Does anyone have another I could Buy or Borrow?? PLEASE? Malcolm. Can't you try the ballast resistor from the other car ? Quote Link to post Share on other sites
guzzitrike Posted February 4, 2007 Report Share Posted February 4, 2007 Guzzitrike,I'm not sure that your understanding of a ballast resistor system is correct. I think you will find that the resistor is part of the normal ignition system and is by-passed during cranking. This resistor is usually ceramic based and consists simply of a length of high resistance wire between 2 terminals, there are usually one or two metal lugs to enable the resistor to be bolted to the engine or chassis. A 12 volt system will have a ballast resistor which reduces the voltage available at the ignition coil to 6 volts and the ignition coil used is actually a 6 volt unit. During cranking, an additional terminal usually found on the starter solenoid or the starter motor (which is operated either by operation of the ignition switch or engagement of the starter pinion) provides a full 12 volt supply to the 6 volt coil, thus boosting the high tension voltage. On some vehicles, including I believe Ford Cortinas and Granadas a resistor cable was incorporated in the ignition wiring loom so you will not see a conventional resistor. Hope this info is correct and helpful. whiteone, Having read your post and reread the manual I was looking at I think you are right - thanks, as I said I am no expert, however it may be worth getting out the multi meter before replacing parts which may not be faulty. Bryan Quote Link to post Share on other sites
malcolm Posted February 4, 2007 Author Report Share Posted February 4, 2007 If I had another Rover SD1 ballast resistor I would have tried it. Fair point about the ignition switch - but my thinking was that the ignition switch seems to be working normally as far as turning on ignition lights and starting are concerned. And in the 'normal' setting the handbrake light is on though there is no power to the coil. I hate electrics Malcolm. Quote Link to post Share on other sites
moe and ess Posted February 4, 2007 Report Share Posted February 4, 2007 Hi Malcolm I also have a morbid fear of car electrics. I had a similar problem on a mk11 granada a few years back and that turned out to be the actual coil at fault replaced it with new never had a prblem after that. moe Quote Link to post Share on other sites
Detcollector Posted February 5, 2007 Report Share Posted February 5, 2007 I had this problem a couple of years ago. Packed up in the car park at a riding stables. Eventually worked out the problem and got home by using a length of house hold mains cable direct from the battery to the ballast resistor connection. I now have a jumper wire attached to the spade connection on the ignition feed that i can plug in if it happens again. This is the easiest way to check the resistor module - just put 12V on the connection and check it runs. In my case the problem was an inline connection on the RHS of the engine bay at the base of the suspension turret. Mines a V8 and it gets hot down there, so I had to take some of the heat shielding out to find it. It may be taped into the harness. Lower voltage coils are used to avoid heating issues, breakdown at high rpm and get sharp responses from the coils. Just making up some numbers to illustrate things:- If we had a 6Volt coil fed via the ignition switch and the resistor droping the voltage to 6V then everything is fine. But when you crank and the voltage drops by 3 volts (9Volts at the battery instead of 12V) you would only have 4.5V at the coil (the resistor is a divider). Bypassing the resistor gives you the full 9V while you are cranking and a healthy spark. So its not as simple as checking for 12v while cranking as it could be lower. (Gets lower with cold engine oil, cold battery, poor battery etc) Quote Link to post Share on other sites
jrv8 Posted February 6, 2007 Report Share Posted February 6, 2007 Hi Malcolm, Give me a call , or a PM , I should be able to help. Regards Jim Quote Link to post Share on other sites
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