Former VWDieselParts.com Forum

I Have what I believe is the slow relay for the glow plugs in my 1981 VW dasher Diesel. What I would like to do is increase the time to at least double or triple the time the glow plugs stay on.
My glow plugs stay on for approx. 7 seconds, I would like to increace that to 14 second or 21 seconds. Can vw glow plugs in good working order take that?
My glow plugs work fine right now, I am just trying to think of a way to make my car start easier on vegetable oil. Right now I have to wait 1 min 30 seconds for my injector line heaters to get up to a reasonable temp.

I am running a single tank system75/25 veg to diesel mix right now filtered to 1 micron.

It doesn't get too cold here high 20's f /low 30's f. and so far it hasn't gotten much below 40 f.

I am just thinking and planning.

As long as my glow plus are working I don't see any need to replace them what I am hoping is someone has come up with a way to "fix" a stock/aftermarket relay to do what I want done.
thanks
mark

To my knowledge, fast glow relay is the time that you mentioned. Slow glow relays are more like 30 to 60 second. You may just get a slow glow relay instead. I had a fast glow relay in my Jetta and it was about 7 to 15 second and I switched it out with what was in my Rabbit and it stays on a lot longer. You could also pull the glow temp sensor and your glow plugs will stay on till you start the car (test it to make sure, some relays might let it stay on while engine is runnging). You will just have to time the glow plugs yourself but by the sound of all your heaters, you already time what needs to happen.

thanks, I will try that. What year of rabbit glow plug relay did you use if you remember? I just read that 77-80 model years had slow glow plug relays. Maybe with an afterglow feature. Was your replacement a simple swap of relays or did you have to make it work?
Thanks again
Mark

I need the glow plugs to stay on longer in order for sort of a cheap Elsbett kind of glow plug. Elsbett SVO kits include modified glow plug that stay on longer. I tried to get to the thread “fast glow plugs with old slow relay “ put for some reason I couldn't get there. I could get to every other thread I tried to get to.
The glow plug relay socket looks the same least in the drawing I saw.
Question
Does it burn out the glow plugs?
Thanks
mark

A longer glow plug cycle may not help as it will only warm the combustion chamber. If the fuel coming in is too cold and gelled, it still may not flow any better until you have heated the incoming fuel. But I could be wrong, I am not (yet) running veggie oil.

If found that by removing the temperature sensor wire at the head's water outlet (not temperature gauge wire, the other one) that the glow plugs stay on longer. Be sure to tape the wire's terminal if you do this.

Bill Longyard

put a 2K to 4 K resistor across the terminals of the disconnected sensor wires ... the relay will stay on longer with the higher resistance ....


or glow twice...

For the last few weeks I am using this Bosch relay:
0 281 003 099
This was the standard relay used by VW in Scandinavian coutries.
It works fine!

I, too have an '81. Contrary to what the books show, mine is a slow glow system. The last time I replaced my relay, they sold me a fast glow relay and I started having to cycle a couple of times before things would work correctly. I finally just disconnected the lead from the temperature sensor and let it time out at 30 seconds. The slow relay would delay about that long when it was very cold anyway, so I'm not doing anything that wasn't already being done.
I've investigated putting in the new Duraterm glow plugs... they make a kit and it sells for around $130. It includes 4 Duraterms as well as a matching relay (made to really reduce the cycle time). I plan on trying it soon. My guess is the new relay will allow the plug to stay on for awhile after starting as well (like the new systems do). This may be an answer for you.