Dead Electrics

[TR8 STEVE]

Hi Guys,

Hope somebody can help with this one driving along today in my 7 v8 sudden loss of power i noticed the rev counter had died then all of a sudden back to life, now this happened a further dozen times in the space of a mile i would stop try to restart sometimes it would and sometimes it refused.
I checked all the obvious no wires off no dodgy fuses then called the A.A He said there is no power at the coil? there is power at the ignition and at all the fuses in the glove box but not at the coil so where am i loosing it, he said it could be a relay? or a fuse thats not located in the main box if there is such a thing if it is a relay can anybody tell me which one and on the fuse subject again if you pull out the IGNITION / AUX then the ignition lights still stay on so are they permantly fed or are they fused somewhere else?.
He crossed a wire from the fan to the coil with a fuse to start the car and get me home but to stop it you have to disconect the wire so its home but i need to get it sorted can anybody HELP!!!!.

Steve...

[Raider]

MMM - I am not the greatest mechanic in the world but how about trying from the fusebox to the coil?

Have you got a manual with a wiring diagram?

There is a ballast resist wire that is in the loom and goes across the top of the gearbox bell housing - (I think). there could be abreak in the wire?

Sorry, probably not much help.

One thing that could be though is an auto-electrician!  ::) If you are like me, not that great once the obvious hasn't worked going straight to a professional may well save you alot of grief and money in the long run - see thread "famous non-starting TR7" ::)

[Malcolm]

This has happened to me with my V8.  Unable to find the break in the circuit I simply ran a new wire from where the loom enters the engine bay to the coil.  I can't remember the wire colour but as Martin says you will find it in the wiring diagram in Haynes or whereever.  It's importtant to get the right one as it is ballasted, only giving the full 12V when you are starting-up and (obviously) going off when you switch off the ignition.

Malcolm.

[Ellis]

Malcolm, do all the V8's have the ballast resistor ???  I know some of the earlier TR7s had in-line resistors.

Steve, certainly running a new wire seems the easiest way to fix the problem. Do you know if the car is using a TR7 engine bay loom or the Rover one ??  If it's the TR7 one, someone may have extended the wires and the join may be where your problem is.

Good luck...

[TR8 STEVE]

Thanks Guys,

As was suggested i am seeking profesional help as at this moment the car is requireing other work possible cracked block so it will be going in to my usual garage tomorrow for a complete check and as he rewired the engine bay when i had the bay painted and swapped to a 3.9 he can put it right  >:( but i will let you know the outcome in due course. Thanks again.

Steve..

[Malcolm]

Ellis.  It depends on the coil you have.  If it's a TR7 type coil then it's supposed to have 6v for normal running and 12v starting.  I expect most V8 conversions will have high performance coils running at 12v anyway.  To be honest I have no idea about my own coil but I patched into the wire (by colour) that would be the ballasted supply on a standard TR7 and all worked Ok.

That's the problem with someone else's conversion.  Using the electrical tester the bulb seems brighter when starting so I suspect mine's still 6/12v.

Hope you get the car sorted out soon Steve.

Malcolm.

[TR8 STEVE]

Hi Guys,

Found the electrical fault  ;D quite simple really the wire for the coil had come loose behind the fuse box and was touching sometimes and not at others  :-/. We also took the heads off and found the gasket had gone on number 1 pot so skimmed the heads fitted new composite head gasket everythings now hunky dory ;D. Thanks for the tips and advise much appreaciated.


Steve...