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Glow Plug Upgrades


LBC28730
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My 1981 505TD runs beautifully once it is going. 
When I first got it, it was a bit hard to start cold, and the PO was using starting fluid to get it going. 

Judging by my limited experience with previous diesel (VW AAZ), I figured that getting fresh glow plugs should sort that out.
Unfortunately, it made little difference (high quality Bosch glow plugs).

I've seen mentions about upgrades that involve individual lines to each GP instead of one shared lead but I haven't seen specifics of where anyone has done that. 
Would it be just literally running an individual lead to each GP from the point that they originate?
I believe this is also relative to what people refer to as a "Manual GP" set up. I still have questions though. 
Would the manual set up still involve some sort of timer or would you just hold a button for a period of time? 

Although, unfortunately, my lovely Zoe is not running at the moment (starter wiring issues I think), this is something I really need to take into consideration as we begin to get into the colder months here in the mountains. 

What are the best options (I will still add a block heater for the winter) to make the XD2S most responsive to starting?

 

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I’ve read about the individual cables to the GP’s as well and did it on my wagon just as maintenance when I replaced the solenoid.  It already had the manual conversion with a toggle for applying the GP’s.

If the car is hard starting even after you replaced them, it would sound like maybe there’s maybe a pump timing problem, injector spray issue, or maybe something else at play - but my first guess would be timing, then injectors.

Not a lot of options for block heaters for these, most likely are the lower block heaters, or silicone oil pan heaters.  

Ive confirmed the turbo gas engines use a 36mm block heater and I found and tested them on the N9TE and it should work, supposed to be the same size for the diesel motors, but I haven’t tested the install yet.

Rabin

 

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Do you have the "fast" glow plugs setup on your 81 car?

From my experience the relay on the control box can be in need of a bit of cleaning, the blue box isn't supposed to be opened but it can be done.

Another important thing to check is the big +12v feed to the control box, for years I changed glow plugs a bit too early and when it worsened I also brought a brand new control box... that behaved just like the old one.

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21 hours ago, Bean said:

I’ve read about the individual cables to the GP’s as well and did it on my wagon just as maintenance when I replaced the solenoid.  It already had the manual conversion with a toggle for applying the GP’s.

If the car is hard starting even after you replaced them, it would sound like maybe there’s maybe a pump timing problem, injector spray issue, or maybe something else at play - but my first guess would be timing, then injectors.

Not a lot of options for block heaters for these, most likely are the lower block heaters, or silicone oil pan heaters.  

Ive confirmed the turbo gas engines use a 36mm block heater and I found and tested them on the N9TE and it should work, supposed to be the same size for the diesel motors, but I haven’t tested the install yet.

Rabin

 

With the manual GP conversion, I can eliminate the control box?

 

I'm thinking about getting a coolant circulating heater such as the "zerostart".

I'll look into the timing as well.

16 hours ago, SRDT said:

Do you have the "fast" glow plugs setup on your 81 car?

From my experience the relay on the control box can be in need of a bit of cleaning, the blue box isn't supposed to be opened but it can be done.

Another important thing to check is the big +12v feed to the control box, for years I changed glow plugs a bit too early and when it worsened I also brought a brand new control box... that behaved just like the old one.

I'm assuming no because everything is stock?

With manual GP control I can eliminate that box altogether, I think?

I'll be sure to check that connection when I do the individual leads.

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Yes - Control box basically gets replaced with the manual / switched solenoid to actuate GP’s by you.

Hard starting is usually pump timing, or poor atomization from injectors from what I read.  There could also be a very slight air leak that prevents fuel pressure from building quickly…

Rabin

 

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  • 2 weeks later...
On 9/12/2022 at 11:28 AM, Bean said:

Yes - Control box basically gets replaced with the manual / switched solenoid to actuate GP’s by you.

Hard starting is usually pump timing, or poor atomization from injectors from what I read.  There could also be a very slight air leak that prevents fuel pressure from building quickly…

Rabin

 

I wonder what the wire was from the alternator that went to that, when I was working out the alternator retrofit and it smoked. 
I've looked at my FSM and haven't found anything directly relative but I am not going to overthink something I will be getting rid of soon, anyway!

I DO still have a decent leak at the IP so that could certainly be a factor and I can't rule anything out until I address that. 

I am working on having other "back up" vehicles before I dive into the IP on this one, as it is my primary DD right now. 

 

On 9/13/2022 at 6:33 PM, SRDT said:

If I got this right :

up to MY82 20s duration

since MY82 8s duration

They changed both glow plugs and control box.

Interesting. So basically the box is just a timer? 
I have seen diesels for sale that say they have the manual update and they don't have this box. 
I guess the major difference is that you just turn it on and count enough to assume it's heated up?

I wonder if the post MY82 had better wiring/GPs to justify such a huge drop in time required. 

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I would love to get a circulating block heater and make everything work properly, realistically, I think this is going to be something that is going to be put up until spring as the temperatures are beginning to approach the single digits (C) here and I am finding a lot of little electrical issues here and there. 
I'll update on my introduction thread regarding the peripheral issues I am dealing with, as they aren't related to the engine/glow plugs

 

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I can't tell you about the older box but the newer one is a bit more than a dumb timer.

It will power the glow plugs for a set amount of time unless you cut ignition or try to start the engine, this maximum duration is for a cold engine in cold weather.

There is a temp sensor inside the box to shorten this duration when possible, it doesn't act on the relay itself but on the light on the dash. This way you are the one shortening the heating time by engaging the starter as soon as the light goes off ; that means you can also choose not to do so if you know the glow plugs are old and need a bit more time.

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On 9/22/2022 at 5:18 PM, SRDT said:

I can't tell you about the older box but the newer one is a bit more than a dumb timer.

It will power the glow plugs for a set amount of time unless you cut ignition or try to start the engine, this maximum duration is for a cold engine in cold weather.

There is a temp sensor inside the box to shorten this duration when possible, it doesn't act on the relay itself but on the light on the dash. This way you are the one shortening the heating time by engaging the starter as soon as the light goes off ; that means you can also choose not to do so if you know the glow plugs are old and need a bit more time.

Ah ok, interesting.

I just assumed when the light went out, they were up to temp. It also occured to me today I think the plugs are only actively heated until the engine is running?

It never really occured to me before but if I'm not mistaken that's kinda of the point of diesel engines?

This makes the manual GP setup make more sense to me as to it's simplicity on operation.

The plugs are brand new.

I do have a small leak at the pump over yet to address so I guess until that's done and I check the timing I can't rule anything out.

I've been dealing with little things here and there like getting my turn signals to work consistently and other little electrical things popping up.

I've found that if I want my fuel gauge to work, I need to not mess with the radio.....😅😅.

I'm waiting on a part for another car and when that arrives I'll be diving in fully to ask the issues with the 505.

I'm thinking I may forgo driving it this winter if I don't fully sort out the fuel/starting/etc issues.

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Some glow plugs can stay on after starting the engine to avoid a rough cold start and cut on emissions, there is usually a more sophisticated control box with external sensors to go with it.

One good thing with the control box is that you are unlikely to burn the glow plugs, you will also power them for the shortest time so they should last longer.

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