My glowplug circuit stops working internittently, there doesn't seem to be any obvious times it happens. Possibly after heavy wet weather for a few days. Can't be sure though. I have changed the door switch, the temperature sensor (for a genuine one). What is a good thing to try next? Glowplug relay? I have a new set of NGK glowplugs which I will fit this afternoon. (Which I know arent the problem, but I replaced the last ones with dirt cheapies)

I have hardwired a push switch into the dash. to enable a start, but often the truck produces clouds of white smoke until it is warm, I guess the circuit isnt keeping the glowplugs on until the engine is warm.

I fully expect the circuit to work propery next time I start the truck, but I just want to get to the bootm of it as it is a right pain in the horse at the mo!

Thanks

Jonny

the glowplugs are not switched on when the engine is running, even when its stone cold.. it could be a simple electrical problem like a bad earth or a loose connection or wire somewhere, or it could even be attributed to the coolant sensor missreading

As Tom says. The tl;dr version of how glowplugs work is that they put some heat into the combustion chambers so that you can get the engine to fire, but once the engine fires they're redundant because the ignition produces more heat per unit time than they will even at idle revs. Accordingly, they're switched off when the engine's running.

^^ although ken, on some modern diesels like the common rail stuff the glow plugs are sometimes on when the engine is very cold and running, it's controlled by the ecu

The glowplugs are on for upto 180 seconds after the engine starts. Usually, they turn off if the rpm goes over 2500 but come back on when the rpm falls below 2500 again. You can sometimes hear the glowplug relay clicking on and off.

I was lead to believe they stayed on for a bit (Like the above post) by my haynes book.

not on a felicia they don't, it's a raw simple car for simple folks, povety spec etc

not on a felicia they don't, it's a raw simple car for simple folks, povety spec etc

The afterglow period is definitely 180s with the engine temperature sensor disconnected. The ECU controls the glowplug relay.

Hi, I have this problem at the moment in my Octavia. The warning light only comes on in 2 extreme weather conditions. If it has been raining hard and them freezes they come on intermitantly during a journey, they go through the normal start up process fine. And, if it is raining constantly the warning light comes on. It seems when there is a high moisture content in the air something is happening. Any ideas anyone? Unfortunately my man that looks after the car can't do the electric side with this issue, so what should be asking when phoning round to book it in or does anyone know a reliable bod in the Derby area. Much rather go on recommendation.

Where did you read that Wikipedia? Put a volt meter across the glow plug buss bar if you don't believe me.

The later ones certainly have a 180s afterglow period. I've grabbed the Felly manual and it seems to agree.

glow plugs are only there to start them on felicia i had a polo deisel with same engine and ecu that never came on after it was started cold none off this 180s