Parking Heater (Part 1)

Okay, yeah. So I said I was going to be gone for a bit and then the very next week I go and start a marathon posting? WTF?! Well, this project isn't done yet, so some things I mention may get redone later in the series. Let's see...

So, What Am I Doing Now?
Having a heater in your camper while you're camping is nothing new. In fact, having one in your VW microbus is nothing new. For many years, versions of the campers had a gasoline eberspacher heater that drew from the main tank. If maintained well, I've heard these work very nicely. I have a healthy respect / fear of gasoline and gas fires, so I never got one, but have looked at the diesel ones for big rig trucks pretty much since the day I started the TDI conversion. They were running in the $1000US range, which was simply too rich for me. Since then, the design has been reverse-engineered by knock-off companies, and you can get one for around $150US. If that seems too good to be true, I'm sure you're right. I took the limited-money-risk plunge to find out.

Diesel Heater

nicked from eBay

A diesel heater is basically a kerosene heater. Fuel is sourced either from an independent source, or you "T" into your fuel system. That fuel line has it's own little pump that feeds the heater. The heater, in turn, ignites the fuel with a small glow plug, drawing combustion air and pushing exhaust outside of your vehicle. The air it is heating is usually sourced inside the vehicle. The unit is controlled with either a simple knob or an LED panel for a thermostat.

In this case, the combustion air intake and exhaust are 1-inch diameter pipes. The heat comes and goes through a 3-inch diameter pipes. I ordered one off eBay for $140US that looks a lot like the one pictured here.

What's in the Box
It arrived quickly, and it is packaged relatively well. The kit included things like zip-ties and clamps, implying that everything you needed was all in the box. If you were going to use the supplied 10L fuel-tank, maybe everything was there. Sort of. There was fuel tubing, a small fuel filter, the fuel pump, the wiring harness, LED screen, the heat unit itself, of course, a paper-ish tube for the intake (plus a crappy plastic air filter) and a corrugated stainless-steel tube for the exhaust. It even included a small (maybe 3.5 inches by 5 inches by 1 inch thick) rectangular "muffler". I quote it because I could look through it unimpeded. Last, the kit includes a poorly-translated instruction booklet.

What's NOT in the Box
So, what wasn't there? The kit does not include flexible fuel line to connect the various fuel bits together. The fuel tubing is stiff and will not fit around the inlet nor outlet of the fuel pump, for example. A short stretch of rubber/viton fuel line (I had some 4mm VW stuff from one of the fuel line replacements I did) fits around both the fuel tube and the fuel pump and the included fuel line clamps from the kit fit perfectly.

The kit does not include a "T" for you to tie into your existing fuel system though the instructions mention it. I recognize that all fuel systems are different, so any "T" they included could have been wrong. I found one for $7US delivered.

The kit does not include any kind exhaust temperature abatement. This could be hazardous since the heater unit is supposed to be installed inside the vehicle with the combustion air/exhaust venting outside. The exhaust is like your car exhaust in that it's going to get super hot. Wrapping that thing with something fire-safe is very important. I found some for about $17US.

Equipment Considerations
I mentioned the crappy air filter. It is a plastic cylinder that fits on the end of the paper air inlet tube. On one end, there are small holes, like on a salt-shaker. The paper tube fits in the other end. In between, there are long slots cut into the plastic. I couldn't tell if there was a medium inside, but I could look through the little holes and see through to the air-tube inlet. Yeah.. that's garbage, so I bought a washable air filter like this for $8US. We camp in high desert, so dust is something we need to contain. Little no-see-um flies could get through the one they supplied. Easy decision.

I also mentioned the "muffler". We don't camp in the wilderness where the noise of an appliance starting up would escape all notice. We camp in state parks and festival parking lots. We have neighbors. Those neighbors rightfully expect quiet hours to be observed, so if the heater unexpectedly starts up at 4AM, it needs to be virtually silent. That small hollow metal rectangle probably won't cut it. In fact, it might actually act like an amplifier. So, I bought this muffler for $23US designed for a motorbike. I will experiment with the different mufflers and may even experiment with muffler packing to see how quiet I can get the heater, testing with a decibel app on my phone.

Locating

refer fridge cabinet. note
false floor in lower left corner

The bus doesn't have a whole lot of extra space, at least not when compared to a full-size RV. I thought about putting the heater on the auxiliary battery tray in the engine compartment. This would expose it to the weather, and force me to put a 3 inch hole somewhere to get the heated air inside. I considered running it into the original stock plumbing but the instructions not-so-clearly say not to do that. So, I looked at locating in the kick-cabinet under the rock-n-roll bed. This had some issues as well. The power was readily available, since the deep cycle battery and fuse panel live there. I could bore holes through the floor for the fuel, combustion air and exhaust, and could source heat-air from right there. The challenge was finding a good location that wouldn't create weird routing for the heated-air hose, nor crazy routing of the exhaust under the bus. And, the whole operation, when combined with the deep-cycle battery, took up a lot of the space in that cabinet. When we camp, that cabinet holds handy things like the hatchet and propane, so I decided to look elsewhere.

Almost 9 years ago, I removed the refrigerator unit out of the cabinet, turning the cabinet into more storage (See from Fridge to Storage). We have used this cabinet to hold our emergency first aid kit, blankets, towels, paper products, etc. It is super useful. It also has a false bottom, from back when the old refer unit used to sit in there. That false-bottom is a little under 3 inches off the cabinet floor, which sits directly on the metal floor of the bus. I decided that I could raise the false floor a couple of inches, and set the heater between the false floor and the genuine floor. This plan would consume maybe 2 vertical inches of currently used space in that cabinet. If I remove the old insulation off the cabinet lid, I'd get some of that space back. One last hurdle: this portion of the floor has a belly pan beneath it. So, any hole I produce will need another hole in the belly pan. Ain't nuttin' easy.

Costs So Far
The running total for this experiment is
$140 - Diesel Heater
    $7 - Fuel Line "T"
  $17 - Exhaust Wrap/Sleeve
    $8 - Washable Air Filter
  $23 - Motorbike Muffler
$195 - Total

As usual, this post has already gotten long and I haven't actually started yet. Thanks for following along, and more next time-

TDI install retrospective: ECU, dashpod and Sensors

Continuing, or should I say completing, the process of back-documenting what I did to put a TDI engine into an old (1972) air-cooled VW bus. Today I cover whatever is left of the install that I didn't already cover. I had intended to focus this post on the ECU, dashpod and sensors, but most of that stuff was covered the last time.

ECU

ECU image nicked from eBay

Like any modern car, the ECU is the brain of the outfit. It's rather small, for what it does, measuring around an inch thick and around 4 x 6 inches rectangular. There are 2 large rectangular plugs that slide and then lock in. One of them is for the harness that goes to the engine. The other does everything else. The engine harness is the more important of the two, but only just barely. I was able to leave that harness almost completely untouched. I just unwound some tape here and there, but otherwise, it routed like the stock TDI implementation. I left the AC compressor plug dangling where the AC compressor would go, but everything else plugs in. Because of the ECU location in the spare tire well, the harness did not need to get extended at all.

The other (non-engine) harness gets interesting. This is where the majority of your sleuthing will take place. Many of the wires go to the fuse box, and many of those fuses are not needed for our implementation. I chose to leave the wires from the ECU to fusebox alone. Instead, I pulled the fuses for the unused circuits and then removed the wire from the other side. This left less of a mess than had I left everything there, but also reduced the risk of removing something I had to put back... Which happened. Other wires go to the dashpod or the relay blocks. I can't really advise much more on this other than to take care as you decide whether a circuit is needed for your implementation or not before you cut it out. Kind of like that "measure twice, cut once" axiom.

Dashpod

TDI Beetle dashpod

I took measurements, and early-on thought about how I could retrofit a TDI dashpod into the bus dashboard. The VW Beetle dashpod is a single mostly-circular (shy of 270* of a 360* circle) face with a thick surround. It could not fit without some modifications to either the dashpod or the bus dashboard or both. I also own a Jetta of the same vintage and took measurements of that dashpod. I probably could have fit that, but then I would have had to re-think a few things, starting with the speed sensor. More importantly, the ECU and TDI fusebox were in the spare tire well 10 feet or more behind the driver seat. In order to get all of the signals to the dashpod, I would need to extend 30+ tiny wires and hope for no signal loss. Instead, I left the wires alone and buried the dashpod in the spare tire well. The engine will not operate without the dashpod wired in, by the way.

FuseBox and Relays

fuse box image nicked from "PopScreen"

As you work your way through the circuits you don't need, eventually you will work your way to the relays. You don't need many of them. Of course, you need the 109 power relay and the glow-plug relay, but as you remove the things you don't need (cooling system pre-warming glow plug circuit, for example), the support stuff falls off along the way. I have both the fusebox and the remaining relays, still in their respective relay holders, living in the spare tire well.

As I mentioned in the secondary electrical post, I will be re-visiting the wiring in the spare tire well as part of my seasonal readiness this Spring. I would like to re-run the wires from the front-to-back using a single cable as well, making the wiring seem more purposeful.

Idiot Lights
I mentioned that the original bus has 2 warning lights (well, 3 if you include the brake warning light). One says your engine is toast and the other says your electrical is fried. Not very useful, but they're better than nothing. The TDI has a few things worth warning you about too. First is a Check Engine Light (CEL), sourced from pin 24, it gets voltage when a code is thrown. Second is the glow-plug light. This will tell you when the engine is ready to start when it's cold. It will also flash at you when certain error conditions occur. This second reason makes the case to have something. Next is the coolant light. This lets you know when you're low on coolant and on the TDI cluster it flashes for some error conditions. Again, good to have. Last of interest are your charging system and oil pressure, just like the old bus had.

If you look back through the blog, you will not find any posts about this. Why? Well.. truth be told, I didn't do any of these. I run the UltraGauge and that alerts me of any code being thrown, so I don't need a CEL independently. I don't run the bus when it is cold, yet, so I don't need a glow plug light yet. When I do, I will tie into the glowplug circuit to light when it is energized. That's a cheap way of getting there. Others have tied into pin 40. For the coolant level warning, I will tie directly into the 2-prong sensor in the coolant bottle. Frankly, I probably should have done that a long time ago. The charging system could be a simple relay that sends a signal when the difference between the battery posts is below 12V. Alternatively, you can create a "real" alternator light by sending switched 12V to one side of a 12V bulb and the other side to the "exciter" terminal on the alternator (labelled D+ or L). The oil pressure is actually complicated because the TDI cluster determines whether the oil pressure is low for the engine speed. If you really want an independent oil pressure message, it might be worth getting an after market gauge. I haven't decided whether I want that or not. I like the simple dash I have now, though the UltraGause does not include oil pressure. So, this is a continuing risk, for now.

I hope these retrospectives were useful. I realize I neglected to re-iterate the deep details that appeared in the original posts. That seemed excessive. Instead, I focused on the big-picture things that worked, expecting interested readers to leverage the search function in the blog or to follow the links when I did it for you.

Prior related posts:
Preparation
Fuel System
Physical Mounting
Vacuum System
Air, Intercooler and Exhaust
Primary Electrical
Cooling
Secondary Electrical

Now that these retrospectives have been completed, I expect my postings to drop off for a while. I have a number of projects all starting up at once, so while I will be generating content, it will be a while before any of them reach a point of post-worthiness, much less align on the weekly cadence I've been on for the last 2 years.

As always, thanks for following along, and I'll get back to posting when there's something complete enough to write about. Peace, Love and Smiles-

TDI install retrospective: Secondary Electrical

Continuing the process of back-documenting what I did to put a TDI engine into an old (1972) air-cooled VW bus. Today I cover what I call the "secondary electrical". This includes everything that isn't responsible for the alternator:battery:starter system. So, this is the radiator fans, the accelerator pedal, the OBD-II plug by the driver seat and any other miscellaneous stuff I can think of.

This is the first post following the announcement of Neil Peart's death, and I can't let it pass without expressing my heart-felt loss. I love Rush and wish Getty and Alex my deepest condolences. With 2112 blasting in my ears, and "with hungry mind and open eyes"... we return to the TDI retrospective.

Random Cables
Beyond the core primary cables, there are a few thicker wires that need to be run between the relay bank and the battery-top fuses. For these, I found wire of the same thickness, and ran them through the hole in the spare tire well, along the top of the rear engine hatch to the battery-top fuse box. This pathway became fairly well used for sending wiring from the computer to the sensors and senders around the engine. To enable that, I expanded the hole from a tiny drip opening to a 1 inch by 2 inch rectangle.

Cooling Fans Circuit

old NB pedal on left, brake switch on right

I had originally tried to re-use the TDI-stock thick relay and control module to control the radiator fans. That was a mess, and didn't work, so I ripped it all out. Instead, I used one of the small battery-top fused circuits for a power source and a switch on the dash to trigger the fans. The switch went into a hole in the metal dashboard that had not been exposed through the vinyl cover, right next to the ashtray. It receives power from an always-on source so I can cool the radiator even when the engine is off. It triggers a standard relay mounted next to the radiator on the passenger side. When triggered, the 12V from the battery-top fused circuit sends 12V to the radiator fans and the little fan on the inter-cooler. This is a simple circuit, but I have found that long bumpy road trips cause the clips to slowly shake off the relay. So, I may need to put a dab of threadlock on there to stop that.

Accelerator Pedal

new pedal

I originally used the accelerator pedal from the NewBeetle (NB). This was a one-year-only part, so when it eventually failed I had to either pay a few hundred dollars for a replacement or swap it out for the more common pedal. The challenge with the more common pedal was that the rheostat was integrated into the pedal body, so I couldn't hide it like I had hidden the NB pedal. The NB pedal had been stowed inside the belly pan, and allowed me to continue to use the original bus pedal. The integrated housing style pedal meant that the entire pedal would be changed, and it would need a support. I still don't like the final look, but it places the pedal in the right spot for my foot, and it drives correctly. The wiring was fairly easy. There are 6 wires attached to a flat pigtail. I extended the wires and ran the 6-wire bundle under the bus from front-to-back, arriving in the spare tire well, and wired into the computer where the pedal originally wired in. I believe I used wires that were just a bit too thin, because I get sporadic limp-mode issues from lack of signal from the accelerator pedal. See Pedal on the Right for details on the install.

Brake Pedal
NOT USED. If you intend to use cruise control, the computer needs to know when the brake pedal has been depressed. I thought about tying into the brake warning system or putting the sensor on the master cylinder. Ultimately, I made a little bracket on the arm of the brake pedal and the switch triggers when I step on the brake. I don't use cruise control, so I've kind of forgotten about this pedal. 10 years later, this may not work at all, so be advised, this may not be a viable solution. You can see a picture of my switch above. No, it isn't pretty, but at the time it was functional.

Fuel Level
NOT DONE. The range of allowed values for the fuel level gauge in the bus is quite different from the range for the TDI. If you want to swap out the original sender, I found one that would work at Summit Racing. I had thought about building a circuit which would translate the reading on the stock sender into the range accepted by the TDI computer, but I shifted onto other things. My thought was that the original gauge could still work, or I could reference what the computer thinks. I may still do this, or just buy something that does it, like the SN34 from Classic Instruments. For now, I am using the stock level sender and gauge; the computer has no idea how much fuel we have. Most of the time, I don't either.

Speed Sensor
NOT DONE. There are a few ways to go after this. I started down a few paths and decided that I didn't need for the computer to know how fast I was going, so I stopped working on it. My first stop was to try to adapt the vehicle speed sensor (VSS) from the TDI. I couldn't figure that out. So, then I looked into getting something that fit between the dash and the speedometer cable. This looks especially promising as there is a company in Britain (RJ Engineered Solutions, VSS link here) that makes a thread-in plug that fits into the back of the speedometer that the cable threads into. It produces a square wave the computer can understand. While writing this post, I ordered one so I could complete the experiment later. I'll post about my findings once I have some. Since I first investigated this, there are more plug-in options (like Dakota Digital), so you may find something that better suits your project than the RJES solution. The last option is to build your own Hall Effect (or other) sensor. Whichever way you go, Dakota Digital also offers a small magic box (SGI-5E Universal Signal Interface Unit) that can adjust the signal from the sensor to the ECU so you can account for a signal mismatch or simply because you got bigger tires... like I did.

OBD-II

UltraGauge

Since I decided against retrofitting the Beetle dash-pod into the dash of the bus, I still needed some engine monitoring. The old bus had 2 lights for monitoring: one to tell you you're out of oil so your engine is toasted and the other to tell you your electrical is shot. Ultimately, your warning system is your ears. Good thing the radio is so lousy, or not there, so you can hear the clamor from the engine bay. That model doesn't work for the TDI: you can't hear a coolant leak or overheating, and by the time you hear the result of the failure, it's too late. So, I extended the signal wire from the OBD-II plug from the rear of the bus to the front by the gearshift. I got a generic OBD-II plug off eBay (it's new, I just avoid Azn) that only had 3 wires: 12V power, ground and signal. The first 2 were easy, wired the 12V to a switched circuit (15) and grounded against the dash. For the signal, I traced the signal wire on the generic and determined which wire from the stock plug matched it. I know that sounds improbable, but it totally worked. Back then, there weren't the BlueTooth OBD-II readers around today. I got a wired one (UltraGauge) for around $80US that's about 1.5 inches tall and maybe 2.5 inches wide that I have jammed into the corner where the dash meets the driver-side A-pillar. I set the screen to show me engine temp and RPM's so I can watch the 2 things I care most about. I love/hate that thing. The longer I go without a coolant temperature issue, the more I realize just how much that $80 gadget saved my engine.

Along the way, I got a ScanTool OBDLink LX thinking I would integrate a more sophisticated graphical dashboard. It is pretty clever, and with a small tablet, a fuller engine monitoring capability is there for the taking. For me, it doesn't make sense until I have the fuel level and speed getting sent to the computer, so the tablet dash will wait.

Heater Fan
I had heat, but when I had my ignition fire, I removed the electrical parts to reduce the load on the circuits up front. If you intend to wire fans for heat, I suggest you find a strong source of 12V power and use an isolated circuit for it. I would just check the power draw for your fans and plan accordingly. You don't want to blow an important fuse because you kicked the fans onto high. I know I will be doing something to restore a defroster at least. I will probably source power from the battery-top fuses rather than the original bus fuse box and then use a new switch rather than the original Vanagon rear-seat heater switch. Because I already have it in-hand, I will probably re-use the Vanagon rear-seat heater unit, though. I'll just need to figure out where to locate it closer to the front of the bus without appearing in the passenger compartment.

Un-Rat-Nest Wiring
I have done this a few times and still need to do more. Unlike all of the other things on this project, this one is most like cleaning your shop or going to the dentist: you never feel like it, but you're so grateful you did afterwards. The original harnesses are not length-appropriate for this application. Along the way, we extended the ones we needed to extend. This step is about shortening all the others so you don't have a big old rat's nest of wire. I have sourced a relay block to re-route all of the relays, and I will be mounting the TDI fusebox as well as tidying up the wiring so it looks like it was all done on purpose. As of now, however, I have only removed the extra wires that were not needed.

There are quite a few wires running from the engine or computer to the front of the bus, but they can be isolated into clumps based on purpose. Accelerator pedal (6), brake pedal (2), ignition (2), OBD-II (1) and the fan switch (1)... so 12 wires. All of them are relatively thin, like 18ga or smaller, because they just send signals, and don't push power. Arguably, all of them could run through one cable of multi-colored wires (like this). If I were to start from scratch, that's probably how I would do it. In fact, I may re-do it anyway and eliminate the occasional signal loss from the accelerator pedal to ECU. If you include the speed sensor and fuel level sender, you will need more than 12 wires, so maybe something like this instead.

Prior related posts:
Preparation
Fuel System
Physical Mounting
Vacuum System
Air, Inter-cooler and Exhaust
Primary Electrical
Cooling

Next related posts:
ECU, dashpod and Sensors