L300 Non-start - Glow plugs and wiring issue

[edlec]

L300 Non-start - Glow plugs and wiring issue


Hi all!

This is probably going to be quite a long post, but I wanted to do as much due diligence as an absolute novice can so that I can semi-diagnose the problem and then check if I’m in the right area.

Van type:

Diesel L300
Model: 0-P35W (HSRGT 2)
Engine: 4D56

I have previously posted about some dodgy fusible links that were melting, and thankfully @sk66 came to the rescue with some replacements. At the time, a few people remarked on the crazy wiring in the van that came when i got it, which ill get back to later. But the fusible link issue was was solved, and have since been okay. Now I have a new problem, which seems all too familiar on this forum.

Here’s a shot of the wiring:

The Problem

The last few times I have started the van, it has taken a lot of trying, waiting, turning over, and white smoke coming out the back. But each time, it eventually has started. Until now, where no matter how much you rev, I cannot get it to kick in. Sounds familiar? Im sure it does as I have about 10 tabs of this forum with people covering the issue.

I started by following the diagnosis list found here:

https://delicaforum.com/index.php?threads/checklist-to-diagnose-a-diesel-delica-not-starting.3715/#:~:text=If the engine still doesn,voltage with a multi meter.&text=If the starter turns when,have a bad starter relay.

1. I turn the key in the ignition and hear a single click.
2. I hear nothing else if i do nothing else.
3. I press the red aftermarket button, and hold it down. When i let this go, I hear another click.
4. I turn the key to start, and it turns over, sounds like it might catch, but doesn’t.

So my thoughts are, based on all the information on previous threads, that it is a glow plug relay or glow plug issue.


The Wiring

So as far as I can tell, someone has installed a manual glow plug relay bypass.




There is a red aftermarket button attached to the van, which when I bought it the fella told me to press and hold for a few seconds when turning on. This button goes through to a Cargo relay switch:




This switch looks similar to the ones used by @greendel here:
https://delicaforum.com/index.php?threads/glow-plug-and-starter-relays.957/post-57370

And in this thread:
https://delicaforum.com/index.php?threads/need-help-deciphering-my-glow-plug-relay.2179/

• Although strangely here, it looks like my blue and green wires are the opposite way round to how @sck_nogas explains they should be.

This Cargo relay when tested one day had zero power to it, but the next day was working as tested by the multimeter, so it might be a dodgy wire. Ignoring that for the moment, when testing today, I put the key in the ignition, and then when holding down the red button, the glowplugs each register at 12v, until I take my finger off the button.


The plan

Okay so this is the bit where I need any advice, points in the right direction, or people telling me that im doing it completely wrong haha.

My idea is to replace the glow plugs with a fresh set. This feels like a no brainer, as it still seems likely that this is the issue, and even if it isn’t, would probably be good to get some fresh ones in. I ordered ones with the part number Md197511, however I am wondering if I need the NGK MD092392 ones instead. Are the supposed to be 6v or 12v? Feel like this should be obvious but im getting a bit lost on it.

Secondly, my next plan is to basically create the same setup of glow plug bypass as already is in the van, just with a fresh set of wires and a fresh aftermarket button. So i’d buy the Cargo 160477z 12V 100A, the same weight of wire, and just refresh all of the system.

Here is a diagram of the wiring setup for this glow plug manual bypass currently:



The green bit goes to this kinda messy middle bit - should this be cleaned up? I read one post about this chafing might be an issue but havent quite worked this bit out yet...





Sorry if I’m overexplaining things a little here, just want to try and be super clear about where everything is going.


I also seem to have a tonne of wires that go nowhere haha, never a good sign. For example this one is not connected at one end, and the other end links to a wingnut? Doesnt look like i need it so should i just remove all these things?



Shopping list:

• Cargo 160477z 12V 100 (or another recommended one!)
• 4 x NGK MD092392
• Wire replacements (is there a specific minimum thickness here?)
• Cool manual bypass button to replace the red button.
• Anything else? Im in the UK so any shop links if they were uk based would be preferred!

Are there any other wires that I should check and replace while im doing this work? Feel like if im sorting out this bit, it might be worth removing and replacing most things with a fresh connector and wire. Does anyone have a classic shot of how all this is supposed to look? I do have a leisure battery in the back that has also stopped working at the same time, but I havent figured out the wiring there yet either, that's kinda my next step after this.


Overall, does this sound like a good starting point? Am i missing anything obvious that anyone can see


As ever, this forum is an absolute lifesaver, and I would've thrown in the towel a long time ago without the threads and help here!
Here's when it was rolling and I took it to Wales with my brother!!




Cheers

 

[sk66]

If you are staying with the manual bypass only, I would not use the 6v glow plugs... I would use 12v plugs instead; ceramic tipped are best but costly (NGK CZ257, HKT JPX-05).

The problem with cheap metal tipped glow plugs and manual control is that you can burn them out pretty easily (the tip explodes). And even the self regulated ones can burn out if they get alternator voltage after starting (14V); but are much better than unregulated.

The wiring for the relay looks correct except that the fused green wire is/should be getting power from somewhere. I would just jumper 80 and 86 together and eliminate the green wire/fuse.




And I would use the OEM relays and wiring unless there is a very good reason not to. Not only is it cleaner, but everything is also up to spec. The only thing is that you cannot ground trigger the OEM relays... On one hand that means running a positive wire to the trigger switch, but very low current and it should be fused in case of short. On the other hand running a ground wire instead would/could trip the relay and burn out the glow plugs should there be a short.

 

[The Tick]

I would bench test the plugs you have now just to make sure they are working, no need to replace what’s not broken. If you had 6v plugs in there and you have been over heating them with 12v you may have burned them.

 

[edlec]

Hi both,

Thanks for the replies, unfortunately have been away from the van for a few days so havent been able to fiddle.

@The Tick definitely my first port of call, to take them out and try the 12v - I think the only reason i wanted to sort the wiring is to know exactly whether there are other issues, as the first day i tested the Cargo relay it was giving 0 readings on the multimeter, and on the second day it was suddenly working.

@sk66 understood on the ceramic glowplugs, thanks for the...tip

Just because I'm still very much learning these bits, and assuming that I'm going to keep the Bypass option, the next step is one of these two:

1. I replace the glowplugs. Then I use your diagram above to sort out the wiring, removing the green fuse wire. Instead of an OEM relay, I get another Cargo (or similar) relay, and then find OEM wires.

or

2. I replace the glowplugs. Then I follow the diagram, changing the wiring, using an OEM relay. Additionally, I then get another red wire from the battery to the bypass button, with a fuse, that makes this OEM relay work. Is that right?

Is there a place to grab a pack of wires/OEM parts? (happy to purchase off yourself @sk66 if you have these bits!)
alternatively anywhere good in the UK to find these bits, or is it just Anayama also?

Thanks all!

 

[sk66]

Is there a place to grab a pack of wires/OEM parts? (happy to purchase off yourself @sk66 if you have these bits!)
alternatively anywhere good in the UK to find these bits, or is it just Anayama also?

Thanks all!

I'll send you a PM... I offer a fused wiring kit to bypass the controller using the OEM relay, and I have 12v glow plugs as well (metal and ceramic).