Engine won't switch off!

[gtmdriver]

An interesting problem.

I started the engine for the first time today and It fired up straight away although it's not without issues.

The big problem facing me at the moment is that when I turn off the ignition the engine continues to run and the digital dashboard continue to operate. The charge warning light also glows. The ignition switch works as it should with the engine on but not running.

I am using a MS2 V3 unit along with the DIY Autotune relay board.

The un-switched 12v supply to the relay board is taken directly from the solenoid/battery,

the earth is connected directly to the engine block and

the ignition live supply is taken from the wire which used to connect to the +ve terminal of the ignition coil.

If I disconnect this ignition live wire the engine stops as it should.

It seems as if there is some sort of feedback occurring but I can't imagine where from.

[andy198712]

Sounds like you need a diode online with the blue wire from the charging light on the dash, band facing the reg, not the bulb if I recall....

I had the same issue. Key off, engine keeps running and charging light on I think, key back on, charging light goes off. Zero effect on the engine!

[gtmdriver]

Sounds like a plan.

I've checked with my meter.

With the engine running and the ignition on there is 14v at the ignition live wire.

With the engine running and the ignition off there is still 6.7v at the wire.

[andy198712]

To test it

Start the engine, turn off the key, engine still runs.

Lift bonnet, pull the blue wire to the charging bulb.... If that kills it, you need to fit a diode easy sure fire test

[Steve Arndt]

I had a relay controlled by my ignition switch to power an extra fuse block with switched key. The relay became faulty and would stick and keep my ecu powered up after key off. Tap of the relay with a knuckle would budge it to open. I replaced the relay with a higher quality unit. If you have a relay it could be sticking.

s

[woodsbuggy1]

I had the same problem with my motor. The diode solved the problem for me. PM me if you need a diode(I bought a 10 pack) would be happy to ship you one if you are in the States.
Kenric

[gtmdriver]

Thanks for the advice (and the kind offer of a diode but I'm in the UK so I'll source one myself thanks).

It seems to be a relatively common problem but I'll certainly pull the charge light wire to see if it stops the engine.

I'm also considering an alternative strategy involving a 10v Zener diode in the ignition controlled power lead. When I switch off the ignition and the voltage drops to 6.7v instead of 12v or 14v the diode will switch off and stop the engine.

[gtmdriver]

I decided to keep it simple and wired a diode into the alternator warning light wire. It now turns off when it's told to.

Thanks for all your suggestions.

[andy198712]

Nice when it does that eh?

[Dale M.]

Late in coming here and posting.... But....

Engine "run on" is common problem with alternator systems, seems there is enough power leaking through ALT lamp to energize a coil and engine continues to run... In your case keeping the main power relay for MS energized....

As mentioned by another contributor...



Dale

[gtmdriver]

Just what I did.

It works a treat.