Hi all,

I have a 1999 (T) Octavia Tdi 110BHP which is a great car except for one annoying problem.

When starting from cold it takes a fair bit of turning over - probably around 6 seconds before it fires with a big puff of unburnt fuel. After that it runs OK - it absolutely flies and turns in around 50MPG and any more starts during the day are fine.

I thought it may be a glow plugs problem so I took them all out and checked them.

Two were dead so I replaced the whole set with brand new ones.

This made no difference to the cold starting though. I then checked wieh a voltmeter between the glow plug supply rail and battery negative. There is no voltage here when I switch on the ignition which seems like a fault to me. My discovery 300Tdi powers up it plugs for a few seconds when I first turn the key.

I have seen from posts on here and the web in general that this may be a glow plug relay problem. If so, how and where do I find it? I am fairly happy around cars with a decent mechanical and electrical knowledge but the Skoda is far more technically advanced than any of my previous vehicles.

Please could some one advise on this, I look forward to getting it starting first time.

Many thanks

Jules

The glow plug relay is behind the trim underneath the steering wheel, there was another thread about the glow plug relay recently with all the details - search is your friend

coolant temp sensor id say, ive seen them fail and cut power to the glow plugs:)

Unplug the coolant temp sensor (down the right hand side of the cylinder head) and re check the glow plugs again.

It looks like you guys were right - I disconnected the coolant sensor and the glow stayed on for around 20 secs I guess. Now have supply voltage at the glow plugs. They also stay energised for a little while after the light goes out. I can also hear the relay click in and out.

Good news anyway - I bet a sensor is cheaper than a new relay

Off to buy one now.

Many thanks

Jules

Hi again -

I have changed the sensor - what an simple job! Why cant all jobs on cars be that easy.

Unfortunately it has made no difference. With the sensor disconnected the plugs come on but with the old, or new one, plugged in, they dont and the car takes a bit of starting from cold. Any further starts during the day are no problem.

When I turn the key to the warning lights on position, and when cranking the engine there is no voltage on the plug supply rail but as soon as the engine fires I get supply voltage on the rail and it stays energised for over a minute before dropping back to zero again.

Could it be that the glow system is working OK and it is some other issue causing the poor cold start? If so, what would any one recommend.

Many thanks

Jules

Have you had it tested to see if any fault codes are stored?

Maybe but not sure could be The Relay:confused:

I haven't had it tested, I guess I need to find someone in east cornwall with VAG-COM.

Maybe I will put a post on here and see if anyone could oblige.

Jules

The glow plugs don't really do much on these engines anyway. Have you tried double plugging the engine?

Double plugging? do you mean cycling the plugs a couple of times?

I have tried turning the ignition on and off a few times before starting - doesn't make any difference though.

Jules

Yes. Turn the ignition on, wait until one of the ABS, airbag etc test lights go out, turn ff and on as fast as you can manage, and try to start when your selected light goes out again.

Has the pump timing been checked?

When was the cambelt last done?

The cambelt is due for change in the next few thousand miles (bracing myself for the expnse) and no, the pump timing has not been checked. Its not been to a mechanic yet for a look, I was just wondering whether it was something I could fix.

Would the timing affect cold start but be ok when warm?

And, is the timing checked / adjusted mechanically or using vag-com?

Thanks

Jules

Pump timing is critical for starting, hot or cold. It can also create a lot of smoke if its out.

When was the cambet last done?

The pump timing is set mechanically but checked with diagnostic equipment.

Hi,

I've got te same problem with my car (2001 elegance tdi). Can someone give me instructions (photos?) to find coolant temp sensor and relay so I can work out where the problem lies.

Have had it plugged into VAGcom before but didnt show up any problems with that. I've just had my timing belt replaced but it was like that before it was replaced!

Any help most grateful. :)

The temp sensor is easy - as you look at the engine from the front of the car, it is on the right hand side at the back of the engine - it sticks out of a plastic housing with pipes attached to the housing.

The four pin plug just needs a squeeze between finger and thumb to release it then pulls off.

There is a simple clip which pushes up from the bottom to hold it in. pull the clip down with a flat bladed screwedriver (dont drop it) and the sensor will then pull out.

Have the new one to hand so you dont drop loads of coolant.

Replacement is, as they say, the reverse of removal - but use a new O ring.

Relay is under the dashboard above the pedals. There is a trim panel covering them. It looks like it just clips in but on my car one of the clips is broken so someone had fixed it in with a self tapping screw.

Once you drop the panel, all the realays are visible.

Mine is still not fixed but I think is actually a fuel drain back issue rather than glow plugs as, when left overnight, there is always a bubble in the clear fuel pipe between fuel filter and engine.

This is not there if I just leave it parked up for a while and then go back to it - hence the reason I thought it was a warm / versus cold start issue.

Jules

Try rubbing some petroleum jelly on the pipe ends, and see if that clears up the bubble then. If it does, then replace the clear line.

Can anyone tell me what relay is the glow plug relay as I dont have a Haynes book of lies and it doesnt tell you in the manual! :(:(

I had a search around on the net and came up with part number 3 281 003 013 but none of my relays have that on! :confused::confused:

I have managed to get a new relay 109 to try and see if that makes a difference but it doesnt so its not that!

Would like to try the relay first before the coolant sensor as I've got a mate with the same car so can "borrow his!" :)