Two unrelated questions

[mystery3]

First question: I'm currently overhauling the glowplug system on my 81 caddy and cleaning up some wiring and am wondering what the part name and or number is for the little box attached to the firewall wired between the gp's and the relay. It's black roughly 3"x3" has a spade connector on either side. I've searched a ton of diagrams on vagcat and can't find it.

Secondly, would it be ill-advised to run a little stale mix gas through my truck? I have about 2-3L in an old gas can, it's plastic so I'm not worried about rust or any particulate matter. It's a 50:1 mix but too old to run in any of my 2-stroke equipment and I don't want to make a trip out to household hazardous waste drop just for this.

[ORCoaster]

Black box on firewall?  The fuse box?  The one with the strip of tin in it? 

I wouldn't see any real damage being done to the fuel system running 3 L of gas in a full or near full tank of diesel.  At one time that was recommended when diesel was the old style diesel not the ULSD we have now. 

[8v-of-fury]

I have run stale gas before. If its got a 50:1 mix its even better.

As long as you got more then half tank it shouldn't harm anything.

[mystery3]

Black box on firewall?  The fuse box?  The one with the strip of tin in it? 

I didn't get a chance to pop the hood on the truck today but why would the gp circuit have it's own oxed fuse on the firewall? Can I delete it? Would I then run the risk of frying my gp relay/controller?

 I will pull it of tomorrow for further investigation..

[ORCoaster]

Most early VW's had that external fuse after the one in the interior of the car.  Maybe it was a second thought by the engineers.  Maybe it was a second engineer that said "Hey, we have a lot of amps running through the interior of the car through that GP relay, shouldn't we fuse that?"  So they did, after the relay under the dash.  

Now you can modify this whole setup, and I heartily endorse it.  See the sticky links or search for Glow Plug mods.  I ran my big draw from the GP's to a Ford relay and then to a fuse distribution box on the firewall.  I have individual 10 amp fuses for each plug.  Really heats em up in a hurry.  
I used 10 (edit after double check) gauge wire to feed the plugs and most of the original wire to feed the distribution block.

[Toby]

It should be noted that crappy parts store wire with poorly crimped connections, like the ones shown, is not an improvement over the stock copper buss bar. It should also be noted that if you actually monitor the glow plug draw at initial heating the draw will likely be more like 30 amps per GP. After the inrush current diminishes each GP will draw 9+ amps, so a 10 amp fuse will blow spontaniously every once in a while. 15 amp is a better choice for the "Pimp ur Glowplugs" sillyness. Taking the load off of your GP relay is a good idea. A Ford solenoid id ideal for this. All the rest is going backward. I almost always find bad GPs in cars with a push button almost never in a car with the stock timer intact. They do tend to develop a higher resistance over time, which is why the Ford solenoid id a good idea.

The easiest way to check your GPs is to monitor GP current and divide by 9.

[theman53]

Black box on firewall?  The fuse box?  The one with the strip of tin in it?

I didn't get a chance to pop the hood on the truck today but why would the gp circuit have it's own oxed fuse on the firewall? Can I delete it? Would I then run the risk of frying my gp relay/controller?

 I will pull it of tomorrow for further investigation..

I used 8gauge wire and solidered the connections. It is overkill as Vince Waldon said 12ga will carry it and 10ga is more than enough, but 8 did me just fine. Solider and shrink tube did the job as well. I don't use the push button I used the factory relay. I have had nothing but success as the glowplugs lasted longer than the precup in the head = approx. 40.000 miles and I still have good glow plugs.
Main thing is I wouldn't remove a fuse ever. I usually add them especially for big draw direct from the battery. I had a fire in an old Bronco when I hooked up a tach temporary. I only used the vehicle once in a while and mice chewed up the temp hookup inbetween months of not using it. I fired it up and then it fired up. Luckily it was only thin wire to feed the tach power and nothing was hurt. Fuses are now my friend and I use them even to hook up temporary things.

[ORCoaster]

Toby thanks for your biased opinion, you are 100% wrong:

It should be noted that crappy parts store wire with poorly crimped connections, like the ones shown, is not an improvement over the stock copper buss bar.

I am running 10 gauge wire here, not crappy autoparts stuff either.  Purchased it from an electric supply store and it's oil resistant.  Also you can't see the solder joints either. 

Thanks for you super expertise though.  I sure some will think it is helpful.  I don't.

Can you tell me the difference in amp draw between the slow glow and the fast glow type plugs. Initial versus once they heat up.   

I have an amp gauge in the car but I am not going to tell you how much the draw is at initial cycle or how it changes over time.  Mine may be different than the book and I am hoping you can tell me what it should be not what it is.  If I blow a fuse I just reach into the glovebox and get another.  So far have not had to.

Go ahead and continue to use the buss bar it is fine for the life of the car.  I just wanted to pull mine so I could source out bad glow plugs faster than having to get in there with an 8 mm wrench all the time.  But do get the big draw off to a Ford relay like we do.  DAS

[8v-of-fury]

15 amp is a better choice for the "Pimp ur Glowplugs" sillyness.

What sillyness do you speak of? How is supplying the gp's with the 12v they're intended for silly? Personally I use 20amp fuses, and a starter relay capable of 60a continuous.

I almost always find bad GPs in cars with a push button almost never in a car with the stock timer intact.

Must be a coincidence.. please, explain to me why they would go bad in a car with a push button over the stock system? Maybe it was someone using old style plugs and holding them on for far too long.. I doubt it was the relay and actual 12v being at fault. I have personally had my manual relay fail and leave my plugs on for WELL OVER A HALF AN HOUR whilst driving.. they still to this day work in the motor they were in.. This was over a year ago, and probably another couple thousand heat cycles.

The easiest way to check your GPs is to monitor GP current and divide by 9.

10a per, 40 total.. divided by 9.. 4.44a for all four plugs on? I don't know about that..

[mystery3]

I'm currently running 10 gauge oil/fuel resistant wire to the original connection (the cable attached to the bus bar) for the time being and am planning on cleaning up the rest of the system which is why I asked about the fuse box. I think I'll move the little fuse box to the interior side of the firewall above the big fuse box. I'm also planning on running a some larger wire and further cleaning up the engine bay side of the gp wiring.

I can't stand the bus bar. I really wanted to run new/individual wires just to get rid of it.

I'll look into getting a ford relay and wiring that up in the future. It might take me a while to find a ford diesel truck in the junkyard, should I be looking into particular years?

[Toby]

[/i]
I am running 10 gauge wire here, not crappy autoparts stuff either.  Purchased it from an electric supply store and it's oil resistant.  Also you can't see the solder joints either. 

What I can see is that the wire, no matter where you bought it, has thick strands. You can see them wrapped around the terminal on the top left connection. If they are soldered, you should redo them. Thick strands of wire mean less copper than in a fine stranded wire. Take a look at the wire VW uses to supply the GPs.

Go ahead and continue to use the buss bar it is fine for the life of the car.  I just wanted to pull mine so I could source out bad glow plugs faster than having to get in there with an 8 mm wrench all the time.  But do get the big draw off to a Ford relay like we do.  DAS

You guys seem to vastly more trouble with glow plugs than I do. I hardly EVER have to replace one. I have 6 running diesels sitting in my yard right now. Volvo 245 diesel, an Audi 5000 TD, an '86 F350 TD, and 3 Ranger TDs with a GTD project waiting for space to get it inside to do the motor swap. I drive all of these vehicles, except the Volvo regularly. In the past year I have had to replaced no glow plugs.... except in the Volvo. It has a push button and a Ford starter solenoid. It had 4 bad glow plugs when I got it about six months ago. The 5 Grand has lost one I fear, but they are several years old. They all start fine and all have stock controllers.

[rs899]

I'll look into getting a ford relay and wiring that up in the future. It might take me a while to find a ford diesel truck in the junkyard, should I be looking into particular years?

The "Ford relay" they are talking about is the common gasser starter relay, found in every Ford pickup in the 60s , 70s and 80s, and probably all their cars , as well.  My '67 F-100 has one- just go to your local FLAPS and get one for peanuts.

[R.O.R-2.0]

I'll look into getting a ford relay and wiring that up in the future. It might take me a while to find a ford diesel truck in the junkyard, should I be looking into particular years?

The "Ford relay" they are talking about is the common gasser starter relay, found in every Ford pickup in the 60s , 70s and 80s, and probably all their cars , as well.  My '67 F-100 has one- just go to your local FLAPS and get one for peanuts.

mine came from a 90s Aerostar van.. there on the drivers side, up front, easy to get at to pull them 

[8v-of-fury]

A universal lawn tractor starter relay works as well, might be able to get that cheaper at a TSC if you have one close.

[ORCoaster]

Toby,  I have to appologize for the out of focus picture, you get that in low light situations, but the wire is actually fine wire as you say.  The pic is out of focus so it does look wider than it really is.  i used the wire VW supplied to the bus bar and it is on the bottom of the fuse block. 

I think the GP problem we all face is that most of us are dealing with them for the first time in our lives.  That is why we are here on this forum looking for information. 

Combine that with the fact that most previous owners may not have used them correctly or maintained them either.  So when we get the car and it won't start we have to figure out why.  When mine did that I noted that the bus bar joins them all up and determining indidvidual performance was a pain in the but.  Knowning that this may be an issue in the future, I own an 81 MK1, I liked the idea of splitting them off to a better individual circuit.  Hence Vinces pimping sticky.