Help me fix P0380 before the goverment takes my car away

flee said:

Now that sounds like a pretty solid fix/upgrade.
Always better to crimp than solder, too.

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Yes it is, but so many of us cheap crimp. Get or borrow good quality crimper designed for the connects.
I've soldered many a wire, but the rigid connection is not optimal in an application where stuff moves around.

My P0380 problem ended up being the glow plug relay. the relay worked, but the feedback to the ecu was not working. changed the relay and all was good. (1998 new beetle) hope that helps

Didn't read through the post, but I had GP errors on the son's car (after doing all sorts of things- verified GP integrity, perhaps replaced, can't recall; voltages were good out on the ends of the harness). I put some foil on top of the offending GP and slipped the wire back down and haven't had an issue with it in probably 1 1/2 years now.

Thanks for the input. I've fixed my issue by threading the glowplugs and using nuts and ring terminals on them. Picture coming soon I hope.

Also, I read that splicing the 2 glowplug wires together will solve the P0380 code if it's a harness issue. Based on my experience I would say that is false.

You can click on the pictures for full size.

Basically I removed the glowplugs, threaded the tops, installed 1 nut a bit more than finger tight, installed the glowplug, put the ring terminal on and then put another nut on.

You have to be careful not to thread too far down or to over tighten the nuts because the top part of the glowplug will spin in the body. One of mine did that a bit but it's still working fine.

One day I'd like to remove the harness and wrap it up better but it's working for now and I have bigger fish to catch right at the moment.

I also relocated the vacuum reservoir. It's always bothered me where it's located.

thanks for the pics. My only concern would be some corrosion developing but it looks like it would be obvious and easy to repair if that happens.

How did you link the 4 wires together to the main harness?

Yes I imagine that I will get corrosion eventually but the harness itself is so easy to make I'll just make up another one. If I have issues soon, next time I'll use a connector at the engine side so I can just quickly swap the harness out. You can't see it in the pictures, but for the ring terminals I slid the glue filled heat shrink down so that it covered the end of the wire to prevent moisture from entering the wire.

I used non-insulated butt crimp connectors to connect 2 glow plug wires to one of the wires and 2 to the other. Then I used the glue lined heat shrink to seal it tight.
Like these but I think I used 10 gauge, maybe 12?
https://www.amazon.com/Non-Insulated-Butt-Connectors-22-18-gauge/dp/B000W20ZVA

Next time go get some marine-grade (100% tinned) wire and liquid electrical tape (you paint it on) to seal the ring terminals and similar after you crimp them on. That will outlast the car. ANCOR makes the wire; it's not cheap but for any place corrosion is a factor it's the "right stuff."

Auto manufacturers are notoriously cheap and thus never use 100% tinned wiring....

I've never heard of tinned wire before, seems interesting. $40 for 100 ft of 14 gauge. Not too terrible.

burn_your_money said:

I've never heard of tinned wire before, seems interesting. $40 for 100 ft of 14 gauge. Not too terrible.

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Use it in boats all the time. Slap the word "marine" in front of any part = 2x the price at a minimum. My truck has a few marine parts in it.

Yeah, but tinned wire really is more expensive to make, and in this case it's IMHO worth the premium. Any time I have to wire something on a vehicle and it's not in the cabin where it's protected from the environment it's what I use.

Genesis said:

Yeah, but tinned wire really is more expensive to make, and in this case it's IMHO worth the premium. Any time I have to wire something on a vehicle and it's not in the cabin where it's protected from the environment it's what I use.

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It's better without a doubt, but most wiring, even in the engine compartment, doesn't need it. I typically use regular copper wire with GXL insulation. Then I carefully use the shrink tubing over the terminal ends. And those typically go into a harness plug with dielectric grease sealing out the moisture.

This application, however, I do think tinned wire would be beneficial since the terminals are exposed. I think I'll make my own harness like this if mine should ever fail.

Thanks for the idea Burn

ToxicDoc said:

My only concern would be some corrosion developing

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Just as a data point, converted one of my Jettas to this system 5 years ago... everything's still as shiny as the day I installed it.

Plus/minus a light coat of road dust, of course.

I was hoping you'd chime in Vince. I got the idea from Vince, so any thanks should be directed towards him.

one more question, is the factory harness 14 gauge, or did you step up to that size?

burn_your_money said:

I was hoping you'd chime in Vince. I got the idea from Vince, so any thanks should be directed towards him.

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No worries, I suspect someone thought of it long before me.... and really, it's just a throw-back to our IDI days.

Like you I went to it after many months of trying to track down a pesky recurrent P0380 that didn't respond to any of the other techniques that seem to have worked for others.

ToxicDoc: I used 10 gauge 'cause I am a belt and suspenders kinda guy, but at 10 amps draw per line and 6 feet or so 18 gauge would have been safe. The factory harness is surprisingly small-diameter as well... it will be metric gauge but I bet it's 18-16 ish, by eye. It does bridge into some very stout wires at the main harness... in the "Glowplug 101" thread near the final pages I show a couple pictures of the connection into the master harness.

Vince Waldon said:

ToxicDoc: I used 10 gauge 'cause I am a belt and suspenders kinda guy, but at 10 amps draw per line and 6 feet or so 18 gauge would have been safe. The factory harness is surprisingly small-diameter as well... it will be metric gauge but I bet it's 18-16 ish, by eye. It does bridge into some very stout wires at the main harness... in the "Glowplug 101" thread near the final pages I show a couple pictures of the connection into the master harness.

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lol, I'm the same say. I just didn't remember the wires being so large when I did my GPs. Thanks for the extra info

burn_your_money said:

I've never heard of tinned wire before, seems interesting. $40 for 100 ft of 14 gauge. Not too terrible.

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https://www.wholesalemarine.com/ancor-14-gauge-tinned-copper-primary-marine-wire-black-81974.html

If you're interested, I found it cheap, $0.17 per foot. even if they made you buy a spool of 50', that's about $8 (and I checked their shipping fee - about $7) for $15 total. This is an excellent price on marine wire.

Yep -- it's not THAT expensive if you stay away from certain chain marine stores

I have a couple spools in my garage of various gauges since I used to own boats (yes, more than one) and wire, of course, doesn't exactly go bad....

I have removed the ends of the harness boots (right at the glow plug) on my last three tdi's, I find the connections expand and don't make good contact, but having the connection exposed I am ample to crimp it tighter and much better for keeping codes away. The threading is too much work for me.. after all I own a tdi lol

steve6 said:

I have removed the ends of the harness boots (right at the glow plug) on my last three tdi's, I find the connections expand and don't make good contact, but having the connection exposed I am ample to crimp it tighter and much better for keeping codes away. The threading is too much work for me.. after all I own a tdi lol

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Yup, I believe that this is more common than people realize. I was worried about messing up a crimp, which is why I decided to just "shim" the connection by using foil (it was also very quick- least amount of work; I'm looking after FIVE TDIs).