[Vwdiesel] slow glow plug relay, no glow light when engine is warm

[Mark Shepherd]

Marc.
It is quite possible that everything is acting normally! Alas the relay doesn't know that the engine is probably a little tired, and needs a little glow despite being warm. 
I've seen the issue on several of these old diesels and even a hint of it on the 1991 GTD. 

The timer 'v' engine heat graph is fixed, yet somewhat variable between relays. Buying a fast relay and fast plugs like Duraterms would be an improvement. 

Another solution is to pull the wire from the sensor on the back of the head. 
This will give you maximum glow time. 
You then decide when to start the car. 
When you do this the glow circuit turns off as normal.

On my first diesel Quantum, I moved the entire circuit into the engine compartment and ran a lead to the relay via a toggle switch in a spare dash slot. 
This gave me the ability to control the time up to the max, AND turn relay off to act as an anti theft!

Regards
Mark

========================================
Message Received: Sep 05 2014, 08:21 PM
From: "Marciano Pitargue" 
To: "vwdiesel at vwfans.com" 
Cc: 
Subject: [Vwdiesel] slow glow plug relay, no glow light when engine is warm

It never rains in San Jose, CA. But last winter, it did a bit, and my fuse
box got wet due to a poor seal of the windshield. (Fixed that I hope.)
So, I ended up changing out the (original ?) crusty metal bodied (slow)
glow plug relay in my 1980 caddy with a plastic bodied glow plug relay
replacement. Supposedly, this glow plug relay is for the slow glow plug
relay circuit that were on the 1980 vw diesel vehicles.

Now, when the engine is cold, like first thing in the morning, I get the
nice warm glow of the glow plug light. However, when the engine is up to
temp, no glow plug light, hence hard starting if the truck sat for about 30
minutes. Before the fuse box wet event, it always used to light up no
matter the temperature of the engine. And it seems the glow plug light
accurately tracks the power to the glow plugs.

Checked the grounds for the relays for corrosion. They seem clean. One
thing I noticed is that when the glow plug light doesn't light, if I unplug
and plug in the (new) relay, sometimes the glow plug light lights. I
suspect that that the glow plug relay isn't correct for my slow glow plug
relay circuit. Or maybe I missed some ground points (I found 2 circular
fobs where a bunch of brown wires connect to.)

Any advice from the group to address this issue?

Thanks in advance.

Marciano, driver of "slo-mo smokey"
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