When the engine is cranking, should the glowplugs still be powered on a picasso HDI? The reason I ask is the car needs to be left for at least another 5 seconds after the glowplug light goes off for it to start when cold. On checking I found out power is supplied for 10 seconds when the ignition is turned on, without the engine running, over a minute when the engine first starts, but there is no power when the engine is cranking.
Thanks
Dave
That sounds about normal.
The glow plugs can stay on for upto 2-3 minutes after the engine has started, to help warm up the combustion chamber and improve emissions. Some makes also turn the glow plugs of when cranking to help starting (reduces load on battery).
It may be that one or more of the glow plugs has failed, but faulty glowplugs on a HDI should not affect starting until the temperature drops below freezing. To test them, the easiest way is to remove them and connect them directly to the battery and make sure the tips glow red within a second or two.
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picasso hdi is same unit as peugeot i take it the light is on for about a tenth of a second sounds more like an air leak and the scavenge pump is having more time to correct it
It's easier just to disconnect the wire feeding them and connect a wire to the + terminal on the battery. Touch the other end on the glow plugs in turn. A good glow plug will give a small spark as the wire touches it. A dud one does not.
It can be done that way, but if you've never done it that way, it's hard to judge what's a small spark.
It's the way I always do it at work, but use a jump wire with a 15A fuse in it. No spark = plug gone open circuit (most common failure) Small spark = Usually ok (still possible for the plug not to be glowing though) Fuse blows = plug gone short circuit.
Even though that method is fairly accurate, it doesn't guarantee the plugs are actually working properly. Other method is using a high current ammeter, and comparing the current draw between the plugs.
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this is very true :-)
although the teaching behind hdi has always been that the glow plugs arent needed in the uk and thats why the light goes straight out
high current ammeter is best where i work they don't have one so i take them out and test them with the boost pack (after testing with a test light)
If you have an ordinary DVM, connecting that, on the 200mV range, across a length of thick wire will give a good high current meter.
The reason you probably see no power at the plugs when cranking would be due to the volt drop caused by the high current used on the starter motor.
just a guess.
sQuick..
Although that engine is fitted with glowplugs it's not supposed to need pre heating. Should start up from first turn of switch. Maybe a little air leak into the fuel line/filter body? DaveK.
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