Glow plug electrical woes?

[dpd]

First of all, a huge thank you to everyone on this board who keeps giving me excellent help, this is the best board on the web as far as I'm concerned! This time, I think the problem has something to do with the glow plug system, although I can not figure out exactly what.

When I turn the key to 'on', I get a rapid buzzing set of clicks from the glow plug relay. Behind the driver's seat, the relay closest to the wall. Not to get too complicated, but maybe they're related: also, when I turn the key to 'start', I get a similar problem, but this one from the starter relay, and the starter solenoid down below as well, they are both buzzing rapidly.

Both problems appeared at the same time, in the middle of turning over in cold-ish weather.

When I unplug the 'load' harness from the glow plug relay, the relay clicks on and off just fine when turning the key to 'on' and back. So the relay seems to be functioning, as far as the coil contacting and giving me continuity across the load pins, on my multimeter. Same goes for the starter relay. With the load unplugged, the relay activates just fine. With the load plugged in, rapid clicking.

I should mention that the cabin light, clock, headlights, everything oscillate like this when one of the relays is clicking, when the load is plugged in to either relay and it is activated. Everything electrical starts flashing in time with the relay clicking.

I think it might be best to ignore the starter problem, and focus on the glow plugs for now. Is this a familiar occurrence for anyone here? A rapid oscillation of the glow plug relay, when the key is 'on'?

Is there any symptom of the glow plug system not working, that they would draw huge current, then suddenly stop, then suddenly draw again?

I have checked the battery leads, they are nice and tight. The cabin fan, my loud stereo, headlights, etc all operate just fine when the relays are unplugged.

Thanks a million, David

[dpd]

I should also mention that I had the starter-part of this problem earlier this year, when it was freezing cold. I waited till it was warm outside to work on it, and what do you know, it was fine, so I put off looking at it. Now the weather is a bit colder again (although nothing extreme) and the problem has resurfaced, along with the glow plug system now.... bummer!

[FalcoColumbarius]

Where are you located? There is going to be a mini meet this weekend (28th March) at the Tomahawk in North Van. Why not drop in and compare notes, this way you can get some hands on exposure.

Falco.

[dpd]

I'm in Edmonton unfortunately :)
Thanks for the suggestion tho.

[dpd]

I'm not at the vehicle now but after calling Mardy and some thought on it, I can't think of why the glow plugs would be draining down the battery so rapidly, unless a) the relay is broken in a WEIRD way, or b) there is a bad connection somewhere that is arcing/crapping out when a big load is put on it, somewhere. So I am going to focus on checking the wires... I already checked the battery's main terminals but I didn't check the 80 amp fused link to the alt/starter/glowplugs.

If that wire is melted down from too much current and hanging on by a few strands, maybe that is enough to be crapping out everything with a big enough draw. Come to think of it the hot wire voltage at the glow plug relay was lower than I expected, around 9.5 volts, which should not be the case unless there is lots of resistance on the wiring, i.e. a bad connection. I hope that's it, and I just had to type it up to figure it out :)

[Green1]

unless a) the relay is broken in a WEIRD way,

relays can fail both open and closed, if they fail closed the glow plugs would be permanently "on" which would drain your battery quickly (and likely destroy your plugs too)

[dpd]

The relay is clicking on and off as it should, when there is no electrical load on the main terminals. Detaching the glow plug / battery leads off of that harness makes the relay function normally, continuity tested.
As soon as the big load is on there, it clicks on and off rapidly again as soon as the coil is energized.

So it is not stuck open or closed. From what I know of how solenoids work, I can't imagine it flipping back and forth like that for any reason, except the coil rapidly losing power. And I can't imagine why the glow plugs themselves would cause the voltage to rapidly oscillate.

So I think it is the battery / terminals / wires. As evidenced by the 3V drop between the battery and the glow plug relay, which is too much for a wire that short and that heavy. I bet somewhere I'll find some melting and burnt metal... I just have to find it. The starter has lots that can fail mechanically and cause weird behaviour, but the glow plugs? Shouldn't they either be on, drawing current, or burnt out, drawing none? Just thinking aloud, thanks :)

[jessef]

Sounds like your battery is toast.

How new is it ?

[Green1]

So I think it is the battery / terminals / wires. As evidenced by the 3V drop between the battery and the glow plug relay, which is too much for a wire that short and that heavy. I bet somewhere I'll find some melting and burnt metal... I just have to find it. The starter has lots that can fail mechanically and cause weird behaviour, but the glow plugs? Shouldn't they either be on, drawing current, or burnt out, drawing none? Just thinking aloud, thanks :)

There is more to it than that, the glow plugs should not EVER reach 12V, they are only a 6v system (run briefly over-voltage for quicker startup)
You should not get 12V at the glow plugs, ever. they are stepped down.

[dpd]

Jesse: I am running two identical AGM deep cycle orbitals. They are less than 2 years old, and have never shown trouble so far...

I also have a pair of Trojan L16s (6 volts) in the back on an isolating solenoid, with an override switch. So I tried joining the banks, WITH my Xantrex inverter charger plugged in too, and the clicking is just a little louder and higher pitched as the multimeter reads 14V.

So I'm pretty sure it's not the batteries themselves, but I think it might be the screw-on posts or the wiring downstream. I was able to have a quick look on a break today and the plastic post-cover is very melted looking, compared to the last time I saw it, so something is getting pretty hot there, which must mean a bad contact right?

Green1: thanks for the heads up! But I was measuring the voltage on the battery-side of the glow plug relay, which is before the step-down, no?

[Green1]

Green1: thanks for the heads up! But I was measuring the voltage on the battery-side of the glow plug relay, which is before the step-down, no?

I can't be certain as I don't recall completely, there are about 3 relay looking boxes under the driver's seat, and I believe one of them actually does the step down (I think the relay you're thinking about is after the step-down, but again, I can't be certain)

[dpd]

Talking to Mardy today, I don't have a glow plug setup like everyone else... with a P25V, aka non-turbo "work van" model (factory camper), the glow plug setup is different. There are only 2 electronics boxes down there, glow plug and starter relay, no step down.

Mardy said my glow plug set up was much more reliable than the standard Delica... I don't know exactly why, maybe I have 12V glow plugs? I don't know enough about the Delica model differences to know.

[Green1]

ah, yes, it sounds like you likely have a "standard" glow system as opposed to the "quick glow" system most of the delicas on this site use, if that is the case, then likely my advice from earlier is incorrect as you will in fact have a 12v system.

things to check:
- batteries (sounds like you're good here...)
- connections, this is the important one, a slightly loose or corroded connection anywhere along the line will cause you trouble.

[mararmeisto]

Talking to Mardy today, I don't have a glow plug setup like everyone else... with a P25V, aka non-turbo "work van" model (factory camper), the glow plug setup is different. There are only 2 electronics boxes down there, glow plug and starter relay, no step down.

Mardy said my glow plug set up was much more reliable than the standard Delica... I don't know exactly why, maybe I have 12V glow plugs? I don't know enough about the Delica model differences to know.

So, if I understand you correctly, you've got the LRLWB (low roof, long wheelbase)?

Regardless, if you've only got two 'boxes', and you're glow plugs run at 12V, then you don't have a drop-down resistor (like the rapid-glow systems), and from the chattering you describe and the steady lights when you disconnect the relays, it's either a voltage problem (but you say your batteries are fine) or a voltage problem (like a loose wire or a corroded connection). You mentioned this all happening after a particularly cold day? There may have been enough contraction to move something loose far enough out of place to provide a poor connection.

Check the glow plug connection; check the battery connections (also check your fusible links); check the connections on the relays.

[loki]

Green1: thanks for the heads up! But I was measuring the voltage on the battery-side of the glow plug relay, which is before the step-down, no?

I can't be certain as I don't recall completely, there are about 3 relay looking boxes under the driver's seat, and I believe one of them actually does the step down (I think the relay you're thinking about is after the step-down, but again, I can't be certain)

I'm pretty sure, but it has been a while since I was mucking around down there, that the initial glow plug relay sends 12V to the plugs(yes I know they are 6.2V plugs) and the drop resistor is only connected to the second relay that is used after the initial hit to get it started.

http://www.delica.ca/forum/glow-plug-ci ... html#p2206

Diagnostics for the GLOW PLUG RELAYS:





Diagnostics for the WATER TEMP SENSOR:





Diagnostics for the STARTER RELAY:





Diagnostics for the DROPPING RESISTOR: