Relays and GP's

[ORCoaster]

92EDJ  Says: Engine mods are fun. More power to the glow plugs don't give you more fun or better starts, it means you have to replace
your glow plugs sooner.

I say in order to enjoy your engine mod you need to be able to start it and that requires a better start.  Modifying the GP system makes that happen.  Unless you live is some really warm climate like AZ or NM and are not in the higher elevations. 

I am with TheMan.  Buy decent GP's in the first place and you can heat them up to where they should be glowing red hot and not have to worry about them burning up. 

Living here where it is generally 40 or 50 when I need to start the car always takes the GPs.  Or at least the relay always goes clunk when I hit the key. 

[Gizmoman]

I am not familiar with a stock Vanagon diesel's glow plug system. Is the glow plug relay under the dash with its rear engine? I hope not.

No, it's all in the bay and the stock wiring was probably fine when it was new (1.6 NA). My comment about the "long run" was wrong, there's no heavy amps going the 20'+ back to the GP's.
However, the circuit has been fried at least once real good (no idea why) and so I'm re-doing most of it inside the engine bay, plus adding some additional stuff to the overall load. I just figured I'd make it tidy and over-do things a bit for a margin of safety. For example, the headlight light switch wiring was probably fine as well. I still added two relays (one for the high beams and another for the low beams). From what I've read, the stock switch just barely handles the load (seen pictures of melted ones) so why take the chance if I'm already into it? Relays are cheap.

[92EcoDiesel Jetta]

I am not familiar with a stock Vanagon diesel's glow plug system. Is the glow plug relay under the dash with its rear engine? I hope not.

No, it's all in the bay and the stock wiring was probably fine when it was new (1.6 NA). My comment about the "long run" was wrong, there's no heavy amps going the 20'+ back to the GP's.
However, the circuit has been fried at least once real good (no idea why) and so I'm re-doing most of it inside the engine bay, plus adding some additional stuff to the overall load. I just figured I'd make it tidy and over-do things a bit for a margin of safety. For example, the headlight light switch wiring was probably fine as well. I still added two relays (one for the high beams and another for the low beams). From what I've read, the stock switch just barely handles the load (seen pictures of melted ones) so why take the chance if I'm already into it? Relays are cheap.

Sounds like you are doing the right thing with the fried wires and all.

[92EcoDiesel Jetta]

92EDJ  Says: Engine mods are fun. More power to the glow plugs don't give you more fun or better starts, it means you have to replace
your glow plugs sooner.

I say in order to enjoy your engine mod you need to be able to start it and that requires a better start.  Modifying the GP system makes that happen.  Unless you live is some really warm climate like AZ or NM and are not in the higher elevations.  

I am with TheMan.  Buy decent GP's in the first place and you can heat them up to where they should be glowing red hot and not have to worry about them burning up.  

Living here where it is generally 40 or 50 when I need to start the car always takes the GPs.  Or at least the relay always goes clunk when I hit the key.  

If you are having trouble starting at 40 or 50F with a stock glow plug system and think that by modifying it will give you better starts you are putting your efforts in the wrong place. You should be checking the compression, starter motor health (RPM) instead. Winters gets down to 10 to 20F's around here and I give my manually controlled glow plugs (stock relay in stock fuse relay panel) about 6 seconds and it fires right up within the first crank with no smoke. I installed a block heater 2 years ago and never plugged it in once because the engine starts so well in the winter.

[flowmastergfunk]

The headlight relays...oh man...I can recommend that 100x over the glow plug relays! I can hardly stress enough how much greater it makes them perform! I suppose it won't make driving any more fun though. You will just have to buy new bulbs sooner

One point, is that you COULD still use the stock single fuse on the firewall, and just have a little octopus harness branching off into 4 different wires, 1 per plug. You could use an ampmeter to check current and see which, if any glowplugs were dead. Yet, still, if you pop that main fuse, you lose them all. This does seem like a fair and simple upgrade, strictly for the purpose of diagnosis, while maintaining use of the stock system. However, 4 times the wire, 4 times the resistance, 4 times the strain on the stock setup.

It has been proven that the stock relay system will start the car in cold cold weather. With the enhanced adaptation (or downgrade, if you prefer), I feel beyond confident that I won't run into a cold start problem in a snow storm...unless I have things shorting out under the hood from being grounded by the elements. Do I want to replace glow plugs more often? Oh HELL no!!! Would replacing burnt out glowplugs from overvoltage in the middle of a snow storm be harder than changing a fuse in the stock system? Absolutely. Am I worried? Nah.

If anything, (for some of us control freaks) perhaps adding a switch to manual override switch in place of the stock relay would be a more appropriate mod to add to the list (in conjunction with the HD mod). Perhaps a plug-n-play unit that fits directly into the stock relay spot, and has a certain length of wire coming out of it to mount a remote on-off or toggle switch. I know not everyone is interested in manually controlling such a function, but this would give you the chance to revert to the timed relay, if desired, without molesting the stock harness. Fully reversible (minus whatever hole you would drill to mount the switch).

If there is worry of burning up the glowplugs from overvoltage, this would seem appropriate.

The timed application...car starts...glow plugs still glowing...hotter and hotter and hotter (even though the car has already started and their purpose is fulfilled) *CLACK* timer shuts off after x-amount of unnecessary seconds.

or

Flip switch...car starts...flip switch...no exceeded wear and tear.

 I feel increase voltage to the plugs getting them hotter faster is an upgrade...yet I can agree with the statement that overvoltage for a prolonged period of time is, comparatively, unnecessary wear and tear.

I really like this discussion though! I am highly interested in seeing the layout of a stock van glow setup as well! I have never seen a diesel van in the flesh

[Gizmoman]

I believe in the stock 82 vanagon there is a temp sensor (water or oil) connected to the GP circuit. If the sensor is "open" (hot), the GP's don't come on. This is probably true for all diesels unless someone has messed with it

[flowmastergfunk]

Ahhhh yes. So true. Look at me....trying to sound smart before coffee hahaha. I put on a pretty good front, if you ask me 

[TylerDurden]

One point, is that you COULD still use the stock single fuse on the firewall, and just have a little octopus harness branching off into 4 different wires, 1 per plug. You could use an ampmeter to check current and see which, if any glowplugs were dead.... However, 4 times the wire, 4 times the resistance, 4 times the strain on the stock setup.

Last time I checked, four wires in parallel had 1/4 the resistance of a single wire.

Coffee good... 

[flowmastergfunk]

HAHAHA this is true...but I think I was still accurate on that part...

Even with a single wire/ribbon, the stock setup is still in parallel. With individual wires, you are multiplying the resistance of wire. 2 feet of 8 gauge wire has less resistance than 8 feet of 10 gauge wire Not to mention whatever kind of resistance would form at the connection of 4 pieces of wire twisted into one lol.

Thank you for keeping me in check though! I am no engineer, I just play one on the interwebs.

[flowmastergfunk]

*drumroll* Coffee, don't let me down on this one! I am caffeinated as all hell right now, so I would have no excuses other than miseducation and flawed thought process!

[mtrans]

IN my Fiat GP start ~ 12 A,then go down to 8-9 A.

[Toby]

You guys have WAY too much time on your hands. The GPs are not going to fail early because they get a full 12v. Your car is not going to burn up because of bad GP wiring unless you have LOTS of other problems. Thees cars start just fine down to 0*F, if you have a good motor with a good battery and starter. Kid F$#king the GP circuit is not going to make it start better. GP life with the stock system has never been a problem. It does appear that GP life IS a problem with manual systems. Checking/changing GPs on an IDI VW has never been a big deal unless, of course, you don't have the skills and/or tools to do the work. There is a message there......

That being said, taking the load off the stock wiring with a Ford starter solenoid is simple, clean, and easy. On an AAZ for instance you can get one to bolt to the water outlet by just elongating one hole. You don't even have to cut one wire to do it.

[TylerDurden]

2 feet of 8 gauge wire has less resistance than 8 feet of 10 gauge wire ...

If the eight feet of AWG10 are 4 pieces, at 2' in parallel.  It's less than half of the resistance of the AWG8.

(The stock system is not parallel, it is one line with a 40A load.)


So which would anyone prefer...

One piece of AWG8 carrying 40A?  ---- or ----  Four pieces of AWG10, each carrying 10A?


(I'll take the four @ AWG10. )


GPs never all die at once, individual lines let you easily determine which one is bad.

Compared to individual lines, the stock buss-bar is a PITA to isolate the bad GP from the good, or to replace any GP except #4.

[8v-of-fury]

I once had a manual system fail on me, where the starter solenoid I had used failed in the "glow" position. Leaving my glow plugs on for my 35 minute drive, and subsequent 20+ minutes afterwords that it took to drain my battery completely flat.

This was 3 years ago, and those glow-plugs are still in a daily driven diesel to this date.. They would have at the time been getting 14v for 35 minutes and then the full battery voltage after I shut it off. Roughly an hour of straight glowing.

Duraterm FTMFW.

[flowmastergfunk]

Yes, Toby. I, for one, certainly have too much time on my hands...but that is neither here nor there I suppose it is better spent on the forum than the slums and brothels of the internet!

I can't argue for a single second that the stock system is a bad design. Form follows function, and the engineers did a damn fine job. Cannibalizing the stock glow plug system will not help a car with a weak battery, low compression, and a weak starter/voltage drop to the starter. It would hardly constitute as a bandaid! It is more of a placebo when it comes to someone having sub-par standings with the aforementioned starting criteria

I have a freshly rebuilt engine, a new starter, a new battery, I live in a tropical @$$ corner of the world...doing the glow setup that I did is certainly like shooting blow-flies with a 12 gauge. I just wanted to After seeing the "pimp your glowplug" article years ago, I felt like I came up with a cleaner and sturdier alternative. Even though...it doesn't look any cleaner than the stock setup! There is even more visible crap in the engine bay, extra parts and ultimately, more chance for failure.

Tyler, although the buss-bar works...I am with you all the way. I have the skills/tools to repair or diagnose it either way, I am just sticking with individual wires for personal preference.

However, the stock system IS in parallel, just an optical illusion. They all share the same positive, they all share the same ground. They LOOK like they are in series because they are all in a row, but remember, series would be wired from positive to negative. Here is a picture example with speakers...

Layout wise, looks pretty similar to our stock glowplug setup, huh?
I can assure you, these speakers are wired in parallel

It's funny, this thread seems strangely similar to a K&N discussion haha. Jeremy! What is your stance on glowplugs! lol

Like I said, I did this just to have fun and make it my own. This didn't earn me an honorary seat as a chief VW engineer, for making "improvements" to the previous design haha.

Just like running a K&N, it is a matter of preference and I think these little cars, if maintained, will keep on puttin either way!

Cheers guys