coxy123 Posted April 17, 2019 Report Share Posted April 17, 2019 Hi, just got a tr7. Non runner. I can get it to turn over but can't get a spark. Any help would be appreciated Link to comment Share on other sites More sharing options...
Anglefire Posted April 17, 2019 Report Share Posted April 17, 2019 Several questions you need to answer to give people half a chance! 1. Points or electronic ignition - does it work? Contacts ok etc? 2. Voltage to coil ok? 3. Plugs ok? 4. Dizzy ok? One way is to see if you have a spark at the centre of the dizzy 5. Rotar arm ok? Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 17, 2019 Report Share Posted April 17, 2019 6. Fuel OK? 7. Fuel getting to carbs? Link to comment Share on other sites More sharing options...
coxy123 Posted April 17, 2019 Author Report Share Posted April 17, 2019 Thanks for your reply. The rotor arm in the dizzy is a strange disc affair. Do I have to take that off to check for a spark. Apologies for being dumb. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 17, 2019 Report Share Posted April 17, 2019 think you need to remove it to check there is a gap at the points when the cam opens them not the best accessible dizzy in the world of triumph Pete Link to comment Share on other sites More sharing options...
coxy123 Posted April 17, 2019 Author Report Share Posted April 17, 2019 The fuel is ok. It's on the plugs. Just no spark . I think the problem could be the voltage to the coil. We put a meter across it and it read 3 Link to comment Share on other sites More sharing options...
coxy123 Posted April 17, 2019 Author Report Share Posted April 17, 2019 Hi Pete. I'm steve with the red spitfire from twiddle day. We checked points look ok as best I can see. Gap was good Link to comment Share on other sites More sharing options...
dougbgt6 Posted April 17, 2019 Report Share Posted April 17, 2019 Steve, with the cap off, the ignition on and the points closed, open the points with an insulated screw driver (or your fingers!) There should be a spark. If not check ignition 12volts is getting to points and coil. Doug Link to comment Share on other sites More sharing options...
dave.vitesse Posted April 17, 2019 Report Share Posted April 17, 2019 It may be the multi-way plug and socket in the ignition switch loom. Try cleaning the contacts with switch cleaner or brake cleaner spray. A high proportion of the electrical problems on the TR7 are caused by corrosion in the many multi-ways in the looms. Dave Link to comment Share on other sites More sharing options...
coxy123 Posted April 17, 2019 Author Report Share Posted April 17, 2019 There is no spark in the distributor when we turn the engine over Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 17, 2019 Report Share Posted April 17, 2019 Is there a ignition feed confirmed at the coil ?? Pete Link to comment Share on other sites More sharing options...
coxy123 Posted April 17, 2019 Author Report Share Posted April 17, 2019 Run a wire from battery to coil Link to comment Share on other sites More sharing options...
Anglefire Posted April 17, 2019 Report Share Posted April 17, 2019 Measure the coil resistance - should be either 3 or 1.5 Ohms. Link to comment Share on other sites More sharing options...
Anglefire Posted April 17, 2019 Report Share Posted April 17, 2019 Also to prove the coil, put something in the end of spark plug lead from the coil (Spark plug would do) make sure the end is on something to ground (Block for example) and apply power to the coil - then disconnect the negative - you should get a spark. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 17, 2019 Report Share Posted April 17, 2019 Is tr7 a balasted feed coil you say when measured you had 3 is that 3ohm across the coil terminals ?? Run a 3 ohm coil on a ballasted feed gives a weak spark Pete Link to comment Share on other sites More sharing options...
coxy123 Posted April 18, 2019 Author Report Share Posted April 18, 2019 I'm assuming it's a 3 ohms balasted coil. What do you suggest Link to comment Share on other sites More sharing options...
johny Posted April 18, 2019 Report Share Posted April 18, 2019 If you have a ballasted ignition system the coil resistance should be 1.5 ohms and if non ballasted 3 ohms. The coils are not interchangeable. If your not sure which type your system is you could measure the voltage at the coil to confirm it: With the ignition turned on but engine not running measure the voltage to earth at both terminals on the coil. The -ve one going to the distributor points should be zero and the other +ve coming from the supply should show about 6 or 12v with the first indicating a ballasted system (a reading of around 8v would be due to having the wrong coil). If the negative terminal happens to show 12v as well it means the points are open and you need to rotate the engine a little to get them to close. Turn off the ignition while you do this.... 1 Link to comment Share on other sites More sharing options...
dave.vitesse Posted April 18, 2019 Report Share Posted April 18, 2019 All TR7 have a ballast resistor in the loom and hence use a 1.5 ohm coil. Some other info - The ballast resistor is bypassed when the starter motor is engaged. The bypass lead come off a connection (relay) on the top of starter motor under the exhaust manifold. Dave Link to comment Share on other sites More sharing options...
johny Posted April 18, 2019 Report Share Posted April 18, 2019 Is it possible to bypass or remove the ballast resistor and so need a 3 ohm coil? I would imagine this is might have been done if the resistor or relay fails so best to check exactly what voltage is being supplied to the coil..... Link to comment Share on other sites More sharing options...
dave.vitesse Posted April 18, 2019 Report Share Posted April 18, 2019 If its is a separate block and not in the loom then just bypass the block, a jumper lead across the block. If its in the loom then generally a lead has to be take back to the ignition switch and fed directly to the coil. There is a way with the 1980 on TR7. The is a a direct feed from the ignition on the left hand side of the coil. This is a simple cable join, you have to open up the joint then solder an additional lead, then re-insulate, to feed the coil. Dave Link to comment Share on other sites More sharing options...
dave.vitesse Posted April 18, 2019 Report Share Posted April 18, 2019 On the TR7 if it looks like there is no 12volts or no connection to the points then its worth checking a number of multi-way plugs and sockets. Follow the leads from the ignition switch, first picture and clean the multi-ways on the end of the loom picture 2. The other multi ways are the two on the passenger side down by your right foot picture 3. Leaks through the bulkhead where the heater pipes come into the car can cause problems with these two multi-ways. Dave Link to comment Share on other sites More sharing options...
coxy123 Posted April 20, 2019 Author Report Share Posted April 20, 2019 Thanks for all you're input.it still won't fire. We think it must be a faulty coil. We've found it is wired as a US car ,with 4 fuses. It has a white/pink ballast wire. So thoughts are to get a new coil, from the comments i have received, I think a 1.5 ohm unballasted coil is the correct one. If someone can confirm this or tell me different that would be good. Thanks Steve Link to comment Share on other sites More sharing options...
johny Posted April 20, 2019 Report Share Posted April 20, 2019 oh dear theres still confusion! A 1.5 ohm coil is for a ballasted system and a 3 ohm for a non ballasted set up.... Have you confirmed what your system is? Link to comment Share on other sites More sharing options...
coxy123 Posted April 20, 2019 Author Report Share Posted April 20, 2019 thought i had. It has got a white and pink ballast wire. So I assumed a 1.5 ohm unballasted coil was correct Link to comment Share on other sites More sharing options...
johny Posted April 20, 2019 Report Share Posted April 20, 2019 ok if youre certain the system hasnt been modified over the years it should be a ballasted one so you need a 1.5 ohm coil. What was the resistance reading of the old coil across the two terminals with all wires disconnected from them? Link to comment Share on other sites More sharing options...
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