Electric shock when changing gear

XJ
1

Finally got my car starting and running nicely.It’s a 4.2 engine from a 1978 Series 3. However I am getting quite a sharp electric shock if my thumb is touching the metal part of the steering wheel when I change gear. Quite a zap, a bit like an electric fence gives. Any ideas what could be causing that. I have new plugs, coil and HT leads. It’s a manual gearbox with overdrive.

2

Do you have any ground straps between the engine and chassis? If you don’t, then maybe the driver is serving as the ground?

Paul

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3

Davey,

that sound very weird!

Typically, low voltage DC is not perceivable at all under normal conditions. An electric fence, even when used with a car battery, has a device like a coil to raise voltage considerably.

In other words, if you can really feel a zap, you not only have put + at the steering wheel (a permanent cause of issues is the series Jaguars’ horn circuit design), but it strongly indicates that you have in fact connected the steering wheel to the ignition circuit (HT). Double check anything you have done to the HT wires. Is the coil o.k.? Check the voltage at the LT terminals.

Good luck

Jochen

75 XJ6L 4.2 auto (UK spec)

4

You have a ZzzzzzRider…

5

Read on another forum ( Triumph ) that the overdrive solenoid might be generating the high voltage and then discharging into the gear stick via a worn wire or switch terminal. Have insulated those with tape and will report back after the next outing.

6

Maybe it’s a static discharge, not uncommon in cars.

7

Good idea! I expected “zap” to go beyond a simple “zip”:wink:

Maybe, to exclude static discharge, Davey, do the same things as otherwise and then touch the steering wheel and the hand brake lever. There should be the same kind of discharge, I guess …

Good luck

Jochen

75 XJ6L 4.2 auto (UK spec)

8

Thanks for all the suggestions. I think I have solved it. I took the gear stick cap off ( with a sharp implement as per a YouTube video) and then taped over the switch connections, which looked very much like they could have been shorting to the metal gear lever. No further shocks, so :crossed_fingers:

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