Glow plug module failure

The connection to the starter relay cuts the power to the glow plugs as soon as you turn the engine over.

Before these new fangled time switches we had a button on the dashboard that you pressed to operate the glow plugs whilst slowly counting off 30 seconds, then you ran the starter. If that didn't work, you put the throttle to the floor and ran the starter until the engine revved (not just started, but revved). Then there were these handles that you poked into the front of the vehicle to start the engine by hand if the battery failed (as it more frequently did), that only really worked with petrol engines though. Guess these days you'd have to take a front wheel off to use one of those. Reminisce over.

The feed from the stater will drop the plugs out whilst cranking- it's not unusal for 4 plugs to draw ~50amps, so cutting them out helps the battery deliver its all to the starter.

The Control module will possbly base pre-glowing upon coolant temperature, and possibly ambient temp also, as well as have a post glow period where the plugs are fired up again either continuously for a time, or cycled on & off after the engine has started to improve cold running and faster warm up.

That all said, it ought to be fairly simple to arrange a manual switch on the dash by fudging connections at the fubar'd controller. If you want a fixed 10second pre glow, then you'll need a timer (a 555) and a small handful of resistors and caps.

Tim.

incude a thermistor so the time varies according to ambient temp. There are older technology options of course

NT

Thanks for the comments, I shall have another look round to find a route from a switch on the dash into the bulkhead and engine room. If it is simple it is unlikely to go wrong again and most of the time it is not needed, anyway. I am giving it a squirt of easy start into the manifold at present.

Regards George.

Instead of

I'd be inclined to fit a replacement module from something know for sensible design, reliability and sensible spare prices. Volvo or VW as my first points of call (the VW intermittent wiper timer from the late-90s Golf VR6 is excellent and I've fitted it to several cars since!) Otherwise car wiring bits & bobs come from Vehicle Wiring Products (web & post) who stock nearly everything, at sensible prices.

If it's purely manually triggered, just ignore the starter feed and simply remember to let go before cranking.

You've missed out the tractors with the smouldering paper instead of a glowplug and the blank shotgun cartridge instead of a starter :)

SteveW

In message , Tinkerer writes

And the engines with a copper plug you heat with a blowlamp plus the ones that you flip the compression off while you hand crank it to speed.

Seriously though, if the battery and engine are in good order then it should start without the glow plugs, it just needs to crank for longer.