Paul vincent Posted February 5, 2021 Report Share Posted February 5, 2021 Hi all can some one please help i got a TR7 1982 DHC , electronic ignition, now when i start the car great it starts up but as soon as i let go of the key it stops each time, change the coil, change the ignition switch, checked the ballast resister as much as i can , can any one tell me what i need to do, im going mad i think, Thanks Paul Quote Link to post Share on other sites
RobH Posted February 5, 2021 Report Share Posted February 5, 2021 Hello Paul - welcome to the forum. First question - have you checked that there is supply getting to the coil when the ignition key is in the 'run' position? As you probably know with the ballasted system there is a direct connection to the coil for starting but when the key is released, the feed comes via the ballast instead. If that isn't happening the engine will switch off again when. the key is released. Quote Link to post Share on other sites
Paul vincent Posted February 5, 2021 Author Report Share Posted February 5, 2021 Hi and thank you for the reply, yes i think there is i tried the wires to the coil, with the ignition on all have power, the white and yellow wire has power to the + side of the coil , the white and slate wire has power to the - side , dont know what one is from the ballast as i understand its in the loom, , i will look and check on it sunday, thank you for the info very kind of you , i will let you know how i get on , thanks Quote Link to post Share on other sites
RobH Posted February 5, 2021 Report Share Posted February 5, 2021 In case you don't have one, the wiring diagram is here Paul: https://drive.google.com/file/d/0B0OCjgNgn85aOEdlYWp6dnFfc2s/view The ignition and starter wiring is on page 4. When the starter relay pulls in the power is fed directly to the coil by the top contact. When non-operated the feed comes via the ballast resistor. There should be 12v on the white wire when the ignition switch is in the 'run' position. The operation of the switch isn't very clear from that diagram but in 'start' power is connected to the top and middle connections (as shown by the red oblongs) in 'run' it is to the middle and bottom connections and of course in 'off' there are no connections made. Is the electronic ignition a new addition? If so is it happy to run from only 6v? Quote Link to post Share on other sites
HowardB Posted February 5, 2021 Report Share Posted February 5, 2021 Rob, This is the updated version of my wiring diagrams with additional information. UK DHC 1980-81 TR7 (2020-09) with pektron fuel gauge & fan details Cheers Howard Quote Link to post Share on other sites
Paul vincent Posted February 6, 2021 Author Report Share Posted February 6, 2021 12 hours ago, RobH said: In case you don't have one, the wiring diagram is here Paul: https://drive.google.com/file/d/0B0OCjgNgn85aOEdlYWp6dnFfc2s/view The ignition and starter wiring is on page 4. When the starter relay pulls in the power is fed directly to the coil by the top contact. When non-operated the feed comes via the ballast resistor. There should be 12v on the white wire when the ignition switch is in the 'run' position. The operation of the switch isn't very clear from that diagram but in 'start' power is connected to the top and middle connections (as shown by the red oblongs) in 'run' it is to the middle and bottom connections and of course in 'off' there are no connections made. Is the electronic ignition a new addition? If so is it happy to run from only 6v? Quote Link to post Share on other sites
Paul vincent Posted February 6, 2021 Author Report Share Posted February 6, 2021 Hi it was on the car when i got it , thank , Quote Link to post Share on other sites
Paul vincent Posted February 6, 2021 Author Report Share Posted February 6, 2021 10 hours ago, HowardB said: Rob, This is the updated version of my wiring diagrams with additional information. UK DHC 1980-81 TR7 (2020-09) with pektron fuel gauge & fan details Cheers Howard thanks Howard Quote Link to post Share on other sites
Andy Moltu Posted February 15, 2021 Report Share Posted February 15, 2021 Sounds like the ballast resistor has failed (think it's inbuilt in the wiring loom on the 7 just like the later TR6s) When you crank the car over the resistor is bipassed so it starts, release the key and the car will stop if the ballast resistor has failed (or isn't connected). If the wire has failed you can simply replace with a separate ballast resistor (As fitted to many cars such as the Stag or Spitfire) - feed a ignition fed wire direct to the resistor and on from there to the coil or put a 12v coil on and ditch the ballast resistor altogether. Quote Link to post Share on other sites
BusheyTrader Posted February 20, 2021 Report Share Posted February 20, 2021 Hi Paul, Has the starter relay, a blue round one, been replaced recently? I ask because the black rectangular relay that Rimmers list and supply on their website didn’t work for me. If fitted as a starter relay, you get the same problem you’re experiencing. The engine will fire up but then die as soon as the key is released. I found this out whilst chasing an electrical issue. The relay I have is this one. https://www.autoelectricsupplies.co.uk/product/1382 SRB400 as used by several British classics including Aston Martin and Jaguar. hope this helps Adam Quote Link to post Share on other sites
Paul vincent Posted February 27, 2021 Author Report Share Posted February 27, 2021 Thanks Adam i will try that out, Quote Link to post Share on other sites
Paul vincent Posted March 28, 2021 Author Report Share Posted March 28, 2021 To Andy Moltu , as im thick, do i just leave alone the wires of the ballast resistor, as it dont work anyway,? as you said, feed a ignition fed wire, is that from the ignition switch if so what one top, 2 middles or bottom from there i can carry on . doze the feed wire go to the + side of the coil , sorry for being a thickco, getting over covid, now onto the car Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.