To glow or not to glow.

[Spearo]

I installed the new glow plugs I bought here:
http://www.delica.ca/forum/delica-parts ... tml#p62915

They will not turn on and pre-heat ie: no click. Once the starter is engaged they start working, and will continue working once the van is running until the engine's warm.
Que pasa?
Thanks for any thoughts here,
Erik

[Green1]

You'll probably have to take a volt meter or test light and start tracing things to see where the voltage does and doesn't exist.
ie:
- do you have power on the bus-bar linking the plugs (if so, the plugs may be defective)
- if you don't have that, do you have power on output of the relays under the driver's seat (if so, the wiring from there to the bus-bar may be bad)
- if you don't have that, do you have power on the input of the relays (if not, check the wiring back to the battery or the fuse at the battery)
- if you DO have that, check the control point on the relays, (if you don't have power there I'd check the glow controller, temperature sensor, or sensor wiring next.)

[RichD]

Since the problem condition occurred after a minor part change, I would suggest that you put the original plugs back in and confirm the glow system operation. If the problem goes away, you have your solution. If it does not, continue your troubleshooting of the glow system circuit with the known good part, not the replacement part.

Pages 16-39 to 16-46 (39-46 in the PDF) Engine Electrical Manual describes all checks you can do with a multimeter to confirm correct operation of the glow system.

[Spearo]

Thanks dudes. I will indeed put the old ones back in and see what happens. If they still don't work, then I could sumise that the new plugs have done something bad to my system. In any case, how could a plug do this? I don't know enough about this I see- I thought a glow plug was a simple element.

If the old plugs work, then I guess I have to buy proper replacement plugs. I thought I did.

Cheers,
Erik

[TardisDeli]

Hi Erik, if they are the wrong model, or non-oem, you could actually cause damage to yr engine. There was a model change early - mid 1993, different voltage and size (the date is abit variable for production, so if you're in that date range be careful). When were at our meet recently at CVI, Butch says he only uses OEM, he showed an example of non oem glow plugs, apparantly when they overheat the tip can burn and fall off, which then broke the piston, which then embedded iinto the cylinder head, poof -- dead engine (the sad pieces of the engine were there for us to handle). I like green1's idea of swapping in your old ones. If you can check & compare the voltage that would be good.

There have been other posts about checking the mother board (see the post from Marsgal42 a couple years ago for her excellent write-up), see if one the resistors or capacitors is toasty coloured form old age and overheating, you can take it to a "Little Old Man who runs a TV repair shop" sort of dude, they are experts at looking at old circuit boards and can solder in a replacement part.

Keep in touch, let us know. Christine.

[Green1]

I like green1's idea of swapping in your old ones. If you can check & compare the voltage that would be good.

not my suggestion, it certainly isn't the first step I'd take... I'd check to see if power is getting to them first, swapping in the old ones doesn't do any good if there's no voltage at the bus-bar, and it's a much quicker/easier check then swapping the plugs out again

[RichD]

it certainly isn't the first step I'd take

Giving him a bunch of threads to chase is only going to expand the scope of the problem or make it worse, not solve it.

If he confirms the old plugs function correctly, he can safely assume that the surrounding system is operating correctly. This isolates the problem area in one step, and most importantly returns his vehicle to an operating state.

[Spearo]

Tested with a light before putting the old plugs back: no juice in pre/start mode, but there once starter engaged and after while the engine warmed. Old plugs remedied the situation.

[TardisDeli]

Hmmm, evil glow. Christine.

[Pacific JDM Parts]

As was stated in the original post only the correct glow plugs will work.
I would return the glow plugs you purchased and install the correct genuine Mitsubishi 6.2 volt glow plugs to insure that you have no other problems.

[Green1]

Tested with a light before putting the old plugs back: no juice in pre/start mode, but there once starter engaged and after while the engine warmed. Old plugs remedied the situation.

Hrmmm... I'm not questioning that this is what happened... I'm just not quite sure of WHY that would happen... what about the new plugs could possibly cause there to be no power feeding them?

[mararmeisto]

Tested with a light before putting the old plugs back: no juice in pre/start mode, but there once starter engaged and after while the engine warmed. Old plugs remedied the situation.

Sounds like you got the wrong plugs...

[RichD]

what about the new plugs could possibly cause there to be no power feeding them?

Impedance.

[Green1]

what about the new plugs could possibly cause there to be no power feeding them?

Impedance.

That still doesn't make sense, if they were too high impedance, they would act as an open and there would be power on the bus-bar, but the plugs would simply not provide enough heat.
if the impedance were too low, they would act as a short, and I would expect the fuse to blow (which would mean that swapping in the old plugs wouldn't work until you changed the fuse as well, something he didn't report doing.)

As I said, I'm not questioning that it happened, I'm just trying to figure out the "why" of it. If I can grasp that, it will give a better idea of the workings of the system for troubleshooting further issues.

[Spearo]

As I said, I'm not questioning that it happened, I'm just trying to figure out the "why" of it. If I can grasp that, it will give a better idea of the workings of the system for troubleshooting further issues.

You and me both. My electrical skills are minimal, but this is weird to me.

In any case, the seller has made some offers to help so far. I'd like to exchange the plugs or be refunded, based on the fact that they don't seem to work in my van. I can't think of any reason why a seller wouldn't take them back and refund the 80 bucks as there is obviously nothing wrong with my van.

I'm just happy no damage was done.

Thanks again for the input,
Erik