Glow plug light does not stay on

Hi guys not sure if its normal or not but my glow plug light comes on for 1 to 2 seconds for the dash board check and then shuts off but when I have a volt meter hooked up to glow plugs they continue to get power for a while after the light shuts off, is this normal? What controls the light if it's not the actual glow plug relay?.....I can hear the relay click off when the power drops away on the volt meter which I know is normal but why does the light not stay on with it?

Probably after glow, if it's a 5 speed, the coolant heaters also stay on until the coolant teaches a certain temp

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I don't think my GP light has stayed on for 2 seconds either.

If you unplug the coolant temp sensor the light will stay on much longer. Maybe 30 seconds comes to mind?

If the car starts OK I wouldn't worry about it.

Yes it's a 5 speed but it's not after glow because I dont even start it I just turn the key on, if I unplug the coolant temp sensor the light stays on for the 20 seconds and feeds the plugs for the entire time the light is on (Bentley manual says 20 seconds) the car does not start ok it shakes and shutters and sometimes the starter will kick out and grind the ring gear because it almost starts but doesnt. I have already replaced the coolant sensor but I'm trying to figure out why the light shuts off before the plugs shut off

"but I'm trying to figure out why the light shuts off before the plugs shut off"

It's designed that way. It's not a problem. Your starter motor however...

Yup, it's a "wait until I go out before engaging the starter" light, as opposed to "your glow plugs have power" light.

Been that way since 1978.

Some folks add an extra LED to the dash so that they actually know when the plugs have (or don't have) power... particularly on the older IDI engines that really needed them to start, even in the summer. Guilty as charged.

Sounds like your glow plug system is working fine, but your starter needs replacement.

Tdijarhead said:

Sounds like your glow plug system is working fine, but your starter needs replacement.

Click to expand...

And/or the injection timing needs to be checked. Late/retarded timing makes for poor cold starts.

Tdijarhead said:

Sounds like your glow plug system is working fine, but your starter needs replacement.

Click to expand...

I agree. The ECU does a good job of monitoring the glow system. No DTC, no problem with that.

Of course, if the ECU gets the wrong information (like the CTS value), then.... but that rarely happens like that, although CTS do fail often.