I suspect I have one or more glowplugs that are about to kick the bucket.

I haven't had a chance to scan the car yet, but do these appear in VAG-COM as an fault code?

If not, is there any way you can find out which is the guilty party?

Tom

if you look on utube vidios tell you how to check them

I suspect I have one or more glowplugs that are about to kick the bucket.

I haven't had a chance to scan the car yet, but do these appear in VAG-COM as an fault code?

If not, is there any way you can find out which is the guilty party?

Tom

Hi Tom

IF you have a duff plug it should show up as a engine warning light, but the best way to test is a plug has gone is remove them

and connect the body of the plug to earth and the tip to 12+ and if it goes red at the tip they are fine if they don't they are duff.

Radiotwo

Hi Tom

IF you have a duff plug it should show up as a engine warning light, but the best way to test is a plug has gone is remove them

and connect the body of the plug to earth and the tip to 12+ and if it goes red at the tip they are fine if they don't they are duff.

Radiotwo

Thanks, I'll give this a shot of Christmas.

I've no engine warning light, but while it starts first time in the morning, there is a cloud of smoke, it doesn't catch as quickly and smoothly as it used (not that it's taking an age of turning over) and for the first second or two it is very rough, like it's a cylinder or two down.

Tom

Could also be the coolant temp sensor is goosed. Common cause of poor starting as the ECU doesn't fuel correctly if it's getting a wrong reading from the CTS.

You won't get an EML for faulty glowplugs. On these cars, the glowplug circuit is very basic - fuse (on top of battery, relay (position 4 on relay plate), a common rail connecting to all glowplugs and the glowplugs themselves.

The only fault the ECU can detect is a short/open circuit on the relay coil, which is indicated by a non-flashing glowplug light that doesn't go out. You haven't mentioned that.

Unless you have access to a glowplug tester, perform the test as Radiotwo in post #3. Using a meter is never definitive.

To test the glowplug circuit, you need to unplug the coolant temperature so the ECU thinks it's icy cold. With the ignition on, check all four glowplug caps. If you get no voltage, check the fuse on top of the battery. If the fuse is OK, you may have a faulty relay.

Could also be the coolant temp sensor is goosed. Common cause of poor starting as the ECU doesn't fuel correctly if it's getting a wrong reading from the CTS.

I've had the temp sensor go twice, but the side affect of that has always been the glowplug light staying on for the max time.

This time, the glowplug light is fine, and the temp guage appears to be working fine. I think I'll plug it into the computer this weekend when it's cold and see how the temp readings look.

Tom

You won't get an EML for faulty glowplugs. On these cars, the glowplug circuit is very basic - fuse (on top of battery, relay (position 4 on relay plate), a common rail connecting to all glowplugs and the glowplugs themselves.

The only fault the ECU can detect is a short/open circuit on the relay coil, which is indicated by a non-flashing glowplug light that doesn't go out. You haven't mentioned that.

Unless you have access to a glowplug tester, perform the test as Radiotwo in post #3. Using a meter is never definitive.

To test the glowplug circuit, you need to unplug the coolant temperature so the ECU thinks it's icy cold. With the ignition on, check all four glowplug caps. If you get no voltage, check the fuse on top of the battery. If the fuse is OK, you may have a faulty relay.

Having checked with the computer to rule out th e temp sender I'll go with the plug test.

Does the supply to the glowplugs only last as long as the glowplug light is on? I mean, will the supply be removed thus the end stop glowing when the light goes out?

Tom

You won't get an EML for faulty glowplugs. On these cars, the glowplug circuit is very basic - fuse (on top of battery, relay (position 4 on relay plate), a common rail connecting to all glowplugs and the glowplugs themselves.

The only fault the ECU can detect is a short/open circuit on the relay coil, which is indicated by a non-flashing glowplug light that doesn't go out. You haven't mentioned that.

Unless you have access to a glowplug tester, perform the test as Radiotwo in post #3. Using a meter is never definitive.

To test the glowplug circuit, you need to unplug the coolant temperature so the ECU thinks it's icy cold. With the ignition on, check all four glowplug caps. If you get no voltage, check the fuse on top of the battery. If the fuse is OK, you may have a faulty relay.

Sorry Rwbaldwin

But you have a lot to learn, before you put comments on the forum please get your facts right !

yes you do get a EML when you get a glow plug fault ( I know as ours has just come up with one) I plugged in Vag-com and it even told

me which plug(came up as no2 cylinder) I took them all out to double check and yes number 2 was dead, just to test I put them back in as

I did not have any replacements and when the EML cam back on I rechecked with Vag-com and it told me that number 4 was faulty, so ordered

a set and replaced and not had a problem since.

This is the second thing you have put on the forum which is a load of rubbish, so as the saying goes:

Put brain in gear before putting mouth (keyboard) into action !

Radiotwo

...Does the supply to the glowplugs only last as long as the glowplug light is on? I mean, will the supply be removed thus the end stop glowing when the light goes out?...

Yes and No

NO: Under normal circumstances, the glowplugs will be on during preheat (when the light is on), during start (key at start position) and for up to 180s after the engine has started. If the engine rpm goes above 2500, then the glowplugs will turn off, but will turn back on if the rpm goes back below 2500

YES: If you are not starting the engine, then the light will only be on during preheat (see above). With the CTS disconnected, this preheat period will be maximised. During testing, I just position the meter so I can see from the driver's seat. I can see both it and watch the glowplug light.

Sorry Rwbaldwin

But you have a lot to learn, before you put comments on the forum please get your facts right !

yes you do get a EML when you get a glow plug fault ( I know as ours has just come up with one) I plugged in Vag-com and it even told

me which plug(came up as no2 cylinder) I took them all out to double check and yes number 2 was dead, just to test I put them back in as

I did not have any replacements and when the EML cam back on I rechecked with Vag-com and it told me that number 4 was faulty, so ordered

a set and replaced and not had a problem since.

This is the second thing you have put on the forum which is a load of rubbish, so as the saying goes:

Put brain in gear before putting mouth (keyboard) into action !

Radiotwo

Given that this Octavia has a common glowplug rail supplying all four plugs, how can the ECU tell which glowplug has failed?