Hi all, I am having a problem at the moment as there is no power reaching the glow plugs, I have just changed 2 faulty ones (open circuit + 18 ohms) does anybody have a circuit diagram ?,is there a fuse in circuit ?,is it relay 109 ? I have had a look in the haynes manual and it says unplug the temp sensor near the water pipes at the battery end of the engine but I cannot see how it unplugs. I will hopefully have a look tonight at relay 109 which I think is the later grey one.OCY Y2000 1.9 TDI

Cheers - Stuart.

Hello

I believe the fuse for the plugs is located in the battery cover under a further clip on cover. A blown one should be apparent straight away. To remove the connector to the water temp. sensor feel under the bottom of it where the wire enters and press and push back towards the wires. then try carefully pulling in same direction toward the back of the engine it should come out quite easily if you have it right.

IIRC relay 109 is for the fuel pump that supplies fuel from the tank to the injector pump and if it is playing up the car won't start. Not sure about skodas but in general if you are getting no power at the glow plugs then either the temp sensor is playing up letting the engine think its warmer than it is hence no need for boosting the glowplugs or the relay that supplies the glowplugs with power is either not tripping over when asked or a dodgy connection is affecting the power-plug circuit.

I would Sam95 recommends and check the coolant sensor plug is okay first then check the fuse

Thanks for the replys, I had a look last night and had a go at unplugging the coolant temp sensor, the only thing I could see was a circlip around the base of the sensor so I pulled it out and then eased the thing out, water pi**ed everyware and so quickly put it back in ! (don't forget to top up antifreeze). After removing the maff tubing I could see there was a holding clip at the back edge so I managed to insert a small screwdriver into the slot and gently pulled the wires and out came the connector. I then turned on the ignition and my testlamp on the glow plug circuit lit up so I will have to monitor the starting to make sure the temp sensor isn't faulty (the glow plugs cut in below 9degs). If relay 109 is for the fuel pump where is the one for the glow plugs (anybody have a relay layout ?) and what resistance values should I be getting with the temp sensor ? cheers - Stuart.

I belive relay 103 is for the glow plugs. Some how they don`t work on full voltage but to a maximum of 11v, mine run at 10.2v I think it is to allow them to work at full power while the starter, while working, is draining the battery.

There must be some sort of resistance some where but I can`t find it. Anybody know what is used. Asked my local Skoda technician but just got a " Don`t know answer ". I wondered if there is a balast type resistor or a resistive cable in the harness?

Also where can you get a deciant comprehensive wiring for the Octavia 02 1.9tdi estate from. There must be something better than Haynes`s. Martin

The glowplug relay is in the footwell, J52

Sorry but J52 means nothing to me. Mines a 1.9tdi Elegance estate 02. And where is the resistance that reduces the voltage to 11v so as to maintain power to glow plugs whilst cranking?

Follow up to my last post. After trying to start my 02 Octavia Elegance in cold weather and having no good results no matter how much electrical checking, I finaly changed the glow plugs for the third time, breaking the bank and buying Skoda`s own costing around £70, it finally started first time, and second time, and third time, all starts at around 0-2 degrees C. So in my case no more NGK or BOSCH glow plugs as my Skoda does not like them.

Any body else change back to Skoda`s own glow plugs and found it starts better?

Also on another recuring problem of the dreaded Overboost and Limp Home Mode, which I also had, check for a very coked up exhaust recycling valve and very blocked inlet manifold. Filthest job I have ever come across cleaning them out including the ports in the Head, but once done no more over boost and MPG went backup. All for the price of a manifold gasket and a bit of hard work.

Speak about this to the trade and they say it`s a common fault on this engine. But they didn`t tell me till I found out the hard way, less profit for them if you DIY it. Good Luck