Coil?

[phart]

Intermittent running problems started up again. Won't start at all when hot. Just checked the coil as per EFI test 5B, my voltage fluctuates between 9.5v and 12v rather than 6v and 9v, there is also a permanant 12v when ignition is on, but not cranking. Can someone tell me what this conclusion means! Is it likely to be the coil or ignition amp? Does anybody also have the resistances for the pri/ sec windings on the coil so I can also check that.

Thanks

[GreenV8S]

phart said:

my voltage fluctuates between 9.5v and 12v rather than 6v and 9v, there is also a permanant 12v when ignition is on, but not cranking. Can someone tell me what this conclusion means!

All sounds normal to me. Are you actually getting a decent spark when it's hot? If not, test at the coil as well as the plug, in case it's an HT/dizzy problem. If it's at the coil then test the coil by briefly earthing the -ve side using a fused 15A wire, you should get a spark when you disconnect. If so, suspect the amp/pickup/wiring. If not, suspect the coil/ignition supply.

[wedg1e]

The primary side would be very low resistance, maybe a few ohms at most. The secondary could well be several kilohms. Another thing to check would be that the coil is not cracked as if it leaks oil the HT secondary will breakdown and flash over - a common problem with x-ray systems!

[dickymint]

Look for sparks shorting through the HT leads by running the engine in the dark.
If it won't start when hot - try the bag of frozen peas on the coil and re-try (frozen chips will work also )
Faulty ignition amp will also break down when hot.

[brap_brap]

For what it's worth, even if it doesn't solve the problem, put in a MSD Blaster coil.
It'll blow away TVR's OEM coil any day of the week.(if TVR bought off the rack like everything else)

Just MHO.

[danny hoffman]

Try a new rotor arm - see the thread re the problems I had with mine