Glow Plug Relay Issues

[Dozier]

I'm having some problems with my gpr staying on. I've replaced it with a new one still no luck.

Any help here would be much appreciated.

[Trips_B]

More details... Year, model, engine

Off the top of my head there is a sensor on the side of the head that tells gp relay the temp of the car.  May be malfunctioning.

Also may be ignition switch related, contacts may be wearing our

[CRSMP5]

wow thats a rough one...

got batt power in, glow plug out... temp sensor for how long to stay on, ground, hot with key and hot while crank..

once you crank after a few sec the relay supposed to turn OFF.. relay actually turns on/stays on while cranking.. why the crank signal.. if it stays on fo rtoo long it will burn up the glow plugs... aka drive it for say 5 min with them on thats their death..

temp sensor.. turns off how long relay stays on.. aka engine hot/cold.. i tend to leve this unplugged and just count in my brain.. but all else fails relay turns on while cranking.. LOL.. then turns off once running...

id say the relay its self is the issue..

he has a mk1 jetta project... cleaned bay... why i mentoned above what it does wires..

[bajacalal]

Temp sensor circuit may be open (bad connection or bad sensor). IIRC the relay should still "time out" after so many seconds regardless.

[Dozier]

I thought it was the relay too. Thats why I bought a new one. What else tells the relay to turn off other than the relay itself when the engine in cold. Yes the relay does turn off within 2 minutes but thats obviously to long.

My apologies about not giving the make model year.

1981 Jetta 1.6TD


DSC_0405 by dozierrrr, on Flickr

I also wired the temp guage wire to the glow plug coolant temp wire. Thought that wouldnt make a issue because the sensor's are the same. Just trying to clean up the wiring a little by running just the one wire and not two. I undid that and still the glow plug relay remains hot for 2 minutes or more. Oh and it does work because I can ground that wire and the glow plug relay switches off and the gauge goes up in temp.

I appreciate everyone's help so far!

[billybobf]

wow that looks clean, are you actually going to run that thing and let dirt get splashed up under that (lack there of) hood?

[Dozier]

Thanks... And I'm not really looking forward to it.

[CRSMP5]

piggy back no work... resistance all screwed up that way...

cranking it should turn it off sooner... does it?

[Dozier]

Damn... That sucks. I guess I'll be doing what you do then. I believe it does turn off sooner with the engine running... But not 100%. Still have not got it on the road and I've only started it twice. I'll will dig more into it once I get it going. any more ideas on what exactly tells that glow plug relay to stop making contact besides heat? Should I be looking somewhere else?

[billybobf]

ok, not trying to thread jack, but in MOST NORMAL CLIMATES, with the bosch fast glow plugs, what cons would there be to hooking up the glow plugs to the switched side of the starter relay? I did this on my car after a fire fried most of the factory wiring, it had moderate compression and with the fast bosch glowplugs it only added a couple seconds of crank time, and in his case would only require a small concealed wire traveling up from the starter to the glow plugs which could help the clean look, especially if it was done with all black wiring

[CRSMP5]

the staarter/temp sensor's timmer are the only things to turn it off...

hitting key tells the relay to turn off like 3 sec after your done cranking.. stick your finger on the relay you will feel it click.. simple test.. disconnect the starter wire.. hit key..

for the temp sensor.. i always founf here in crap ohio... when really cold out the temp timmer seems too short.. why i do not connect it... in summer count to 15 and hit key... winter... let light cycle 2x..