Flash Posted August 25, 2021 Share Posted August 25, 2021 I'm in need of some guidance from the Leyland A series experts out there in old school land. Our Moke is running a 45D distributor that has been converted with a little electronic unit rather than the usual points setup. I've recently started experiencing a spark related issue on initial startup from cold after the Moke has stood idle for a few days. Some diagnosis on my part has revealed that when cranking the cold engine I get no spark at the plugs until I back off the ignition key at which point I get a momentary spark. Checking the voltage at the coil positive terminal during these conditions confirms a voltage of 9.2 volts whilst the starter is cranking with no spark at the plugs. If I check the voltage on the same wire with the ignition key engaged but the starter motor disconnected I get 12.6 volts. My first question to those in the know is whether a voltage drop from 12.6 volts down to 9.2 volts during cranking seems like an excessive drop ? Then if I charge the battery up overnight and again check the voltage on the coil wire during cranking I get 9.74 volts and consistent sparks at the plugs. My second question is does it seem reasonable that the slight increase of 0.5 volts should be sufficient to enable the coil and distributor to do their job correctly? Then in terms of finding a permanent solution to the issue : 1. Could my starter motor be on its way out thus resulting in the large voltage drop during cranking ? 2. Could my battery be on its way out thus resulting in a drop in available voltage when not boosted by an overnight trickle charge ? 3. Could there be something else causing the issue ? Any help would be greatly appreciated. Photo of offending vehicle, just cause I know you all like pics. Ta in advance. Quote Link to comment Share on other sites More sharing options...
tortron Posted August 25, 2021 Share Posted August 25, 2021 thats an excessive voltage drop on the battery, probably its on its way out. A battery load tester is about $20 if you want another gadget for the shed, or can take it to a supercehap or whatever to test assume you have the correct ohms coil for the electric distributor, and have gotten rid of the ballast resistor Quote Link to comment Share on other sites More sharing options...
locost_bryan Posted August 25, 2021 Share Posted August 25, 2021 What type of electronic unit? Possible it might need a minimum "reference" voltage? Quote Link to comment Share on other sites More sharing options...
tortron Posted August 25, 2021 Share Posted August 25, 2021 fwiw, 9.6v is about the lowest you would expect an ok battery to drop when cranking 2 Quote Link to comment Share on other sites More sharing options...
Nominal Posted August 25, 2021 Share Posted August 25, 2021 Just did a test on my Morrie. My battery is good. 11V at battery when cranking. Probably the low cranking voltage is upsetting the electronix. 1 Quote Link to comment Share on other sites More sharing options...
Unclejake Posted August 25, 2021 Share Posted August 25, 2021 1 hour ago, Flash said: Some diagnosis on my part has revealed that when cranking the cold engine I get no spark at the plugs until I back off the ignition key at which point I get a momentary spark. That sounds like a crook ballast resistor. Do you happen to have a GT40R coil? EDIT: One way of gaining more information would be to disconnect the starter solenoid and retest voltage to the coil on simulated cranking. It may be a combination of a bad battery and bad/unrequired ballast Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 1 hour ago, Unclejake said: That sounds like a crook ballast resistor. Do you happen to have a GT40R coil? EDIT: One way of gaining more information would be to disconnect the starter solenoid and retest voltage to the coil on simulated cranking. It may be a combination of a bad battery and bad/unrequired ballast On simulated cranking (ie ignition key turned fully, but exciter wire for starter disconnected) the voltage reading on the coil wire measures 13.56 volts. This compared to 13.8 volts across the battery terminals before running the test. The coil is a red Bosch GT40 with no ballast resistor. 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 2 hours ago, tortron said: thats an excessive voltage drop on the battery, probably its on its way out. A battery load tester is about $20 if you want another gadget for the shed, or can take it to a supercehap or whatever to test assume you have the correct ohms coil for the electric distributor, and have gotten rid of the ballast resistor Thanks for the reply Tory. you raise a good point regarding the coil. Its a standard Bosch GT40 with no ballast resistor. It was the original that I was running when I had points. So maybe it's not the correct coil to be using with the electronic unit. Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 2 hours ago, locost_bryan said: What type of electronic unit? Possible it might need a minimum "reference" voltage? Hiya Bryan, I've got no idea what unit it is. Does this photo provide a clue ? Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 2 hours ago, Nominal said: Just did a test on my Morrie. My battery is good. 11V at battery when cranking. Probably the low cranking voltage is upsetting the electronix. Ta for running that test @nominal. I should have checked the voltage across my battery when cranking. I'll do that next time I'm out in the shed. Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 Thanks heaps to everyone who has responded thus far. So I'm thinking the next step should be for me to check the voltage across the battery whilst cranking the starter. If its around the 9 volt mark then its probably in questionable condition. If that's the case I might just connect up a good battery from one of my other cars and see if that resolves the issue. I'm also starting to wonder if I should be replacing my old GT40 coil with something else. 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted August 25, 2021 Share Posted August 25, 2021 Pertronics set ups want minimum 3 ohm coils if I remember correctly, can't use a coil that was for a ballest resistor system (i. E if it's a gt40R) The high performance coils also caused problems, due to the output 1 Quote Link to comment Share on other sites More sharing options...
Unclejake Posted August 25, 2021 Share Posted August 25, 2021 28 minutes ago, Flash said: might just connect up a good battery from one of my other cars and see if that resolves the issue. I'm also starting to wonder if I should be replacing my old GT40 coil with something else. It does sound like a battery problem or a poor earth problem, which is great news IMO. WRT coils: IIRC the GT40R was a coil with a built in internal resister and the GT40 expected an external resistor. Both were designed to run the points at lower voltage after the engine had fired (i.e. when the starter motor was released) to save damage to the surfaces of the points. I dunno what your electronic system will want, but you don't have points so perhaps your coil is still suitable. I'll let others guide you on that point as I'm out of my depth Good luck, and what a gorgeous car 1 Quote Link to comment Share on other sites More sharing options...
Nominal Posted August 25, 2021 Share Posted August 25, 2021 48 minutes ago, Flash said: Hiya Bryan, I've got no idea what unit it is. Does this photo provide a clue ? Looks like the Powerspark kit. See here, says coil resistance should be > 1.5 ohm https://blog.simonbbc.com/2019/04/24/fitting-a-powerspark-electronic-ignition-kit-picture-guide/ 2 Quote Link to comment Share on other sites More sharing options...
tortron Posted August 25, 2021 Share Posted August 25, 2021 Gt40 fine, gt40R not fine 3 Quote Link to comment Share on other sites More sharing options...
GuyWithAviators Posted August 25, 2021 Share Posted August 25, 2021 9 minutes ago, tortron said: Gt40 fine, gt40R not fine I have electronic ignition from a MG Metro (?) in my Austin 1300. Using a Bosch GT40 coil. Starts and runs fine. /lingor out 1 Quote Link to comment Share on other sites More sharing options...
Nominal Posted August 25, 2021 Share Posted August 25, 2021 Oh, if we are doing ling posts, I have a whole Nissan N12 dizzy in my A-series. No issues in about 18 years. 1 Quote Link to comment Share on other sites More sharing options...
tortron Posted August 25, 2021 Share Posted August 25, 2021 How many hours running tho 2 1 Quote Link to comment Share on other sites More sharing options...
Flash Posted August 25, 2021 Author Share Posted August 25, 2021 Thanks to everyone for the additional info shared. I'm going to chuck the battery from my ute into the Moke first thing in the morning and see what voltage I get at the coil during cranking. The ute battery is less than a year old so I know its a good one compared to the one currently in the Moke which was already installed when we bought it almost 4 years ago. It's got no date stamp on it so I've no idea how old it actually is. Talking about the Moke battery I see its rated at 325CCA. Does this sound about right ? If I'm still getting low voltage at the coil even with the good battery then I'm thinking it might be my starter motor that is getting a bit tired and might be sapping to much energy from the battery. I've already cleaned up my battery connections, all of my earthing points and the connections on my solenoid and starter motor, so I'm pretty confident that its not a wiring related issue. I'll report back in the morning. 4 Quote Link to comment Share on other sites More sharing options...
hohocc Posted August 25, 2021 Share Posted August 25, 2021 300CCA was what my old Hunter had in it's early days so your 325 is probably about what the Moke had when new. However if you do end up buying a battery there's probably bugger all difference pricewise in buying something a bit bigger. Hunter was much better when it had 550CCA. By comparison, my wife's Mazda 2 has 450CCA in a little shopping basket, admittedly there's more electric stuff in it than in a 70s British car. 1 Quote Link to comment Share on other sites More sharing options...
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