Allan
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Registered: 05-2003
Location: Plymouth, Devon
Posts: 151
Karma: 14 (+14/-0)
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Glowplugs, glow plug, rail, starting problem.
I've taken a number of calls about starting problems relating to Glowplugs.
Briefly, diesels are started by compressed air. The hotter the air, the easier it is to ignite. The purpose of the glowplugs is to heat the air in the combustion chamber so it's easier to ignite. Glowplugs are powered by a relay and a timer, sending voltage to the plugs for a certain number of seconds. When the timer runs out, the relay should turn off the voltage.
If the engine becomes progressively harder to start during cold weather, or idles roughly and often produces white smoke for several minutes after finally starting, this suggests a problem with glow plugs.
Here are the most common calls.
1. A bad supply to the rail. (This is aluminium wavy bar, going from front to back over the top of the glowplugs.) Check the wires and nuts attached to the rail. They may be rusty, corroded or loose.
2. A poor or loose connection between plugs and rail. Check that all the 8mm nuts are tight. Do not over-tighten them as this can cause the plugs to crack.
3. The relay has stuck, continuing to feed power to the plugs and caused them to burn out.
4. The plugs have worn out due to old age!
5. The wrong plug has been fitted.
Glow plugs can be checked with a tester and by measuring their resistance or continuity. Lack of continuity or excessive resistance indicates that the plug is duff.
If you don’t have a tester, faults are sometimes visible – look for damp, corroded or heavily carboned (blackened) ends on plugs.
Last edited by Allan, 13/Apr/2007, 12:25 pm
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13/Apr/2007, 12:08 pm
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