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General Information => General => Topic started by: maxfax on March 19, 2011, 06:53:09 pm

Title: Glow Plug Relay
Post by: maxfax on March 19, 2011, 06:53:09 pm
Does the VW GP relay rely on the load of the gp's to control the amount of time it stays on??  I'm toying with the idea of using one of these as basically a timer to control the big GP relay on my Olds..
Title: Re: Glow Plug Relay
Post by: Vincent Waldon on March 19, 2011, 06:54:50 pm
Nope, coolant temperature.
Title: Re: Glow Plug Relay
Post by: maxfax on March 19, 2011, 06:58:51 pm
That's what I thought..  Thanks Vince!
Title: Re: Glow Plug Relay
Post by: Vincent Waldon on March 19, 2011, 07:43:29 pm
No worries... here's the relay pinout in case you decide to experiment further:

(http://i197.photobucket.com/albums/aa85/vwaldon/glowplugrelaypinout.jpg)
Title: Re: Glow Plug Relay
Post by: maxfax on March 19, 2011, 08:01:56 pm
Excellent!!  I was just trying to make out the goofy tract diagram when you posted that..  Thanks!

You don't happen to have the temperature to resistance of the VW temp sensor to you??  I need to decide on making an adapter for the VW sensor, or finding one that is comparable that'll screw in the intake..  I'm debating about just trying a simple temperature dependent on/off switch..  As I've been operating them manually I've found that it either needs them run a certain amount of time, or not at all...
Title: Re: Glow Plug Relay
Post by: coke on March 19, 2011, 08:50:01 pm
Looks like the diagram I made when I thought about putting the relay under the hood instead of in the fusebox. :P
Title: Re: Glow Plug Relay
Post by: Vincent Waldon on March 19, 2011, 09:10:04 pm
I've never seen an actual chart unfortunately... the sensor ranges from something like 30 to 300 ohms, with 30 being very hot and 300 being very cold.   ;)
Title: Re: Glow Plug Relay
Post by: maxfax on March 19, 2011, 09:28:25 pm
That'll give me something to go from..  Most of the various temp sensors in my stash run from 1000 to 10,000 ohms, so It's looking like an adapter for the VW sensor is the way to go..  There's already a temp switch for the timing advance solenoid and fast idle..  If need be I suppose I could incorperate that into the mix...   Time for some trial and error testing..

Thanks yet again Vince!
Title: Re: Glow Plug Relay
Post by: Vincent Waldon on March 19, 2011, 09:34:25 pm
No problemo... please do us all the favour of posting back as you learn!  ;)
Title: Re: Glow Plug Relay
Post by: maxfax on March 19, 2011, 09:38:56 pm
Will do..  It might come in handy for the next crazy sob that buys an Oldsmodiesel with an obsolete gp controller...  ;D
Title: Re: Glow Plug Relay
Post by: lovinthedeez on March 20, 2011, 04:56:51 pm
if not trying to make it look stock, why not just run a push button ignition switch to fire a plain old napa solenoid to fire the little suckers.  and hi brett.  :-*  I'm baaaaaaaack.  never sold the jetta, and getting ready to tear it apart......again. :P  Been busy with my new wheelie machine.  69 honda trail k/o that I stuffed a 125 into.  street legal, needs no mirrors or turns ;D
(http://img21.imageshack.us/img21/9861/trail3.jpg)
(http://img859.imageshack.us/img859/3179/trail2.jpg)
(http://img146.imageshack.us/img146/3069/trail4.jpg)
(http://img843.imageshack.us/img843/1114/trail1.jpg)
Title: Re: Glow Plug Relay
Post by: maxfax on March 20, 2011, 05:54:07 pm
Hey Bobby!!   Nice wheelie machine!  That thing looks great for it's age!!!  I'm glad you were able to hang on to the Jetta too!

I have a push button rigged on there for now, that's a rig in itself....  Nice thing about it is it already had the big starter-like solenoid for the glow plugs.  But the electronic module that controls that is dead, and not easily replaced..  This is on an '81 Cutlass diesel, and the car is nice enough that I'd kinda like to keep it stock looking if I can.. Many have opted to use the controller from the 6.2L powered trucks..  I'd have to go find/or buy one of those though, and I already have tons of VW parts about.. 

At some point I'd like to change the type of GP's in it too..  This car has the GM version of fast glow gp's.. Basically what they did was use 6 volt gp's and pulsed 12v to them..  For the time being I have a push button connected to the solenoid, with a turn signal blinker wired in there.. I'll have to keep the blinker even with the VW relay till I get that changed..

Here's some pics of the beast..  Needs washed, the birds have been having their way with it...
http://s295.photobucket.com/albums/mm124/maxfax3/Cutlass%20Diesel/ (http://s295.photobucket.com/albums/mm124/maxfax3/Cutlass%20Diesel/)
Title: Re: Glow Plug Relay
Post by: maxfax on March 20, 2011, 09:24:27 pm
There are crude figures with lots of room for inaccuracy.. Using a heat gun and temp gun this is what I got for rough and rounded readings from a MK1 GP temp sensor..  Temp is in Deg F

Temp     Ohms
30         3200
50         1400
100         200
150          80
200          40
250          20


With no temp sensor, the fast glow relay stays on for about 45 seconds..
At 30 it runs for about 25 seconds, 50 it runs about 12 seconds..   Doesn't seem to come on at all much over 70 deg F..  

Title: Re: Glow Plug Relay
Post by: maxfax on March 20, 2011, 11:27:16 pm
D'oah!!  Forgot to time the GP light.. 
Title: Re: Glow Plug Relay
Post by: blackdogvan on March 25, 2011, 10:45:48 am
I've found a GP relay that is way better than the "normal" MK2 TD relay. The normal relay turns off as soon as the engine starts & stays on with just ignition power foreever on my setup. This Kraker relay turns off after a bit before start & stays on for 5-10 seconds after start.

 Kraker 443911261
Title: Re: Glow Plug Relay
Post by: rabbitman on March 25, 2011, 11:56:40 am
D'oah!!  Forgot to time the GP light.. 

My gp's usually stay on about 5 seconds longer than the light. I've never timed it though and it probably changes with coolant temp.
Title: Re: Glow Plug Relay
Post by: maxfax on March 25, 2011, 03:40:50 pm
They time the GP's stay on after the light goes out is varied by temp..  Just haven't timed it in different temps to see how much it changes..   

Blackdogvan, the original Mk2 fast glow also stays on after the engine is started.. When the relay receives a crank signal it's almost like another clock is started..  This amount of on time for the GP's is also varied by coolant temp.. Once again, I haven't timed it to see exactly what happens.. 

I got impatient and just threw the thing on the car..  It seems to work quite well on this application...
Title: Re: Glow Plug Relay
Post by: 92EcoDiesel Jetta on September 20, 2011, 12:11:45 pm
There are crude figures with lots of room for inaccuracy.. Using a heat gun and temp gun this is what I got for rough and rounded readings from a MK1 GP temp sensor..  Temp is in Deg F

Temp     Ohms
30         3200
50         1400
100         200
150          80
200          40
250          20


With no temp sensor, the fast glow relay stays on for about 45 seconds..
At 30 it runs for about 25 seconds, 50 it runs about 12 seconds..   Doesn't seem to come on at all much over 70 deg F..  



What accuracy would you say these numbers are? Thanks!
Title: Re: Glow Plug Relay
Post by: maxfax on September 20, 2011, 08:38:09 pm
I'm not sure how accurate those numbers are, I'd say within a few degrees and several ohms pending on the temp...   To give you a better feel for them:

My ohm meter was dead on as it was just calibrated and I did clean the contacts so the resistance should be pretty accurate.. However it was a used temp sensor so I'm sure there is some variance from a new one, and I'm sure new ones vary between batches and manufacturers..  According to the documentation, my temp gun was accurate to +/- 3 degrees F at 1" distance.. It is however well abused so I would suspect that could be more..  I was measuring temp on the surface of the sensor, instead of the air temp so that should help with accuracy..   
Title: Re: Glow Plug Relay
Post by: maxfax on February 18, 2012, 07:02:16 pm
I referenced this thread for coolant temp sensor values, and realized that yet again, I didn't follow up!  Vw GP relay works absolutely dandy on the Olds diesel..   Matter of fact, the car has been sitting for almost 2 months and fired right to life...