Low voltage at coil

[LenT]

Car was off road for number of years, 20 years plus. When first back on the road last year, all was ok for first 200 miles, starting perfectly. Overtime however started to take longer and longer to start up, now won’t start and only getting 2.5 volts to coil.

Can anyone help please.?

Len

[Doctordiesel77]

I'm assuming that you checked voltages to earth? If so then check the voltage at the white wire on the cooling fan switch, if this is also low then check ignition switch. If voltage here is ok, try connecting a wire from here to the white wire on coil + side. If car runs ok now then there is a broken wire/dodgy connection in harness... If voltage at ignition switch is low, test the brown wire at switch, if it is ok then switch is faulty, if it is also low then check all of the brown wire connections on battery/starter. Good luck! John

[Doctordiesel77]

I am assuming here that it is an R series engine? If it is an S series there will not be a white wire on the fan switch & there are a few other possible causes for low voltage at coil. If you don't have a Haynes manual, Pete Cooper (Sussex Pete on here) has one, I think for cost of postage.

[LenT]

Hi
Thankyou for the info The engine is a Series S. All the electrics are working apart from the spark- HELP

[Doctordiesel77]

Hi
Thankyou for the info The engine is a Series S. All the electrics are working apart from the spark- HELP

Could be a corroded connection on the ignition ecu, often just unplugging and plugging back in fixes it. The feed from ignition switch goes to ecu, then there is a feed out of ecu to coil, iirc all of these 'ignition live' wires are white, so if you unplug ecu one white should be 12v with ignition on. With ecu plugged in all of the white wires should be 12v with ignition on (I think there is a few seconds delay built in somewhere)

[HIF44E]

I swear by Deoxit. It's no ordinary contact-cleaner. My background is electronics. Yes, unplugging and re-plugging may swing it - only Deoxit will keep it working. Pricey though.