Diesel Starting Probs - Preheat Glow plugs Ignition Circuit

Talk about the 406's electrical system, what wires do what, how to add extra functionality, etc.

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fuvureju
1.8 16v
Posts: 63
Joined: Sun Mar 07, 2010 9:44 am

Diesel Starting Probs - Preheat Glow plugs Ignition Circuit

Post by fuvureju »

Oki - my car is having trouble to start

the key is that the glow plugs are not being energised. - No Light on and no start.
Oki i thought the pre-heat relay was intermittent but on replacement stil no glow light

The glow plugs seem to be fine...I can start the car by bypassing the relay and feeding the glow plugs direct from the battery...glow plug light comes on and car starts.
the interestng thing is after this, the car will start fine and the glow plugs pre-heat as normal without doing this bypass.

I have tested the circuitry with voltmenter and the wiring seems fine...

I am stumped.
is there something else that controls the cicuitry and voltage to the relay?

any suggestions...before i head to a garage on tuesday (after the bank holiday)

I have a Puegeot 406 1.9 TD (XUD9TE) 1996
fuvureju
1.8 16v
Posts: 63
Joined: Sun Mar 07, 2010 9:44 am

Re: Diesel Starting Probs - Preheat Glow plugs Ignition Circ

Post by fuvureju »

Oki

I have finally found the problem

there is a direct live feed from battery via connectors on the starter motor and the alternator to the glow plug relay (10mm screw)
although the voltage feeding in to the relay was checked and seemed good, I had not checked what current was being drawn when the preheat circuit was live.
It now seems that there is a fault in the connector point at the starter motor which means the current drawn leads to a voltage drop when energising the pre-heat circuit.
So I have now just fed a wire direct from battery to the glow plug relay and all works fine.

3 days of diagnosis from everything to a new glow plug relay purchased at 65 pounds, to checking the ignition barrel contacts and replacing of 2 glow plugs (I have not replaced no1 o no2 glow plug as I need to remove the injector pump and i really dont want to do that.

anyway hope this helps for any who may find themselves in a similar situation

PS Why does the lead have from the battery to the glow plug relay have to be routed via the connector points on the starter motor and alternator?
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