Hapy Heat Repeat (Part 1)

Ask anyone who has owned or simply driven an old air-cooled Volkswagen in not-Summer and 9 times out of 10 they will regale you with tales of being cold. These awesome vehicles were designed to have heat, its just that they were also designed to be owner-maintained, and maintaining the cabin climate control is not easy. With aftermarket replacements of J-tubes for heater boxes, cardboard pieces eventually failing over time and long channels under the car (where road salt, etc gets in), it's no wonder heat doesn't make it. Anyway, today's post documents another attempt to get some warmth into Hapy, specifically onto my feet and maybe even onto the windscreen.

Why the Obsession

By now, you must wonder why am I so focused on getting heat into the bus. And I get it. Put on a coat or something, right? Besides, it's not like we really get snow in the Northwestern Willamette Valley. This is all true. For folks who own these cars and busses in genuine snow country, I suspect either they are summer-only vehicles or you are far more brave than I, driving in moon boots or something. Around here, we really only have about 10 weeks of warm-to-hot weather out of the 52 in a year. For the rest of the year it is either cold or cold and raining. Driving around in the cold is not as fun when you're bundled up (ski-gear head to toe) and still cold. Regardless, the temperature is hovering around the dew point during those 42 weeks, and overnight for most of the 10 weeks of warm-to-hot season. In the mountains, it approaches the dew point earlier in the evening and remains later into the morning. So, having a means of getting the fog off the windscreen, and not adding to it, is super important.

The Plan

so it begins

Last November, I posted an update (see: Hapy Update) where I replaced Hapy's crappy glow plugs with a new set. I did not circle-back on that since, but he has started without a hitch all winter. Those plugs are fantastic. The real test will be how well they behave next winter. Anyway, in that post, I mentioned that I had acquired a Maradyne Fans heater unit and shut off the Vanagon rear-seat-heat unit because I believed it had started leaking again. We had a "break" in the weather (almost 10*C / 50*F and only occasional rain), so I took the unit out to Hapy. The think was to remove the old, and swap in the new. Ain't nuttin ever that easy, but it's in now.

Old Heat Exit

The Vanagon rear-seat-heat was suspended from beneath the belly of the bus just forward off the radiator. I had fab'd a custom plenum from the heater unit into the original 3" diameter air channel, run coolant lines along the driver side to feed it and run electrical from the dash to control the fan. I hadn't tried to control the valve, choosing to leave it on or off by setting the valve before a drive instead. I unplugged the electrical first, then the flashing/plenum that routed the air into the 3" channel. Then I set to removing the heater from the underside of the bus. Both of the nuts at the bottom of the threaded bolt supporting the unit had rusted so I had to encourage them with a hammer.

Last, the coolant lines needed to be removed. I held the lines closed with vice grips so I did not lose a bunch of coolant and then set a dishpan underneath so I didn't spread coolant all over the ground when I disconnected things. The lines removed easily enough and a small amount of coolant dribbled into the pan. From this I concluded that the unit had been the source of the leak in the cooling system or there would have been more than the few ounces that appeared. I set the unit aside and shifted to the new heater.

New Heater Hung

mounting angle

For installing the new unit, I started with placement thinks. I wanted it in essentially the same place, running air into the same 3" diameter hole. The force and size of this new unit dwarfs the Vanagon rear-seat-heat unit, however. The Vanagon unit is 6" tall and about 9" wide. The Maradyne unit is also 6" tall, but it is almost 18" wide. The Maradyne unit arrived with a cover that had 3 3" vent protrusions. The outer edges of those protrusions are 13" apart, so I decided I would retain the cover and enclose the vent protrusions inside my new plenum. I was unable to reuse any of the old piece.

After some failed attempts to place the heater straight/level with the ground, I shifted the mounting hardware so the new heater was at approximate 45* angle with the bus, pointing upwards. One would reasonably assume this would cause the unit to hang considerably lower, but because of the placement of the fans, the unit is only about an inch lower. How? Well, in this configuration, the top edge of the heater unit nearly touches the floor of the bus. Neither the Vanagon rear-seat-heat nor this unit could do that in the horizontal position because of all the various pipes running under the floor. In the picture on the right, here, the heater looks much lower than the radiator; that is probably caused by the angle I held the phone. In reality, the radiator is a hair lower. The mounting brackets have 2 holes, designed to be used with the enclosed screws. Yes, that's right, screws, and short ones at that. With this install design weakness in mind, I suspended the heater from a pair of metal tubes under the bus floor with.. wait for it... cable ties. Yeah, that is so RoadKill; I am not a fan of using cable ties this way. Having said that, I have not ever experienced a failure with cable ties, and if my 20-year history with Hapy is any guide I will be up under this bus fairly frequently. So, I will be able to monitor the health of these ties and resolve before any real issue arises.

Plumb It

With the heater relatively stable, I flipped to the driver side of the bus and started working on the coolant lines. As I mentioned in the referenced post from November, I picked up an old-skool control valve. Prior to installing, I noticed that the valve seemed to operate more like a shut-off valve than a gradual taper. When "closed", it was definitely closed, but it remained mostly shut through about half of it's travel, then opened up very quickly through the next 1/4 of it's travel and then that last 1/4 its no more open, in fact it almost seems to close a little bit. So, from closed to open the valve really only had to move a little over 1/4 of it's overall travel. I chose to drill out a little bit of material at the barely open part of the valve so that the first 1/2 of travel now actually opens a little bit near the end of that movement. Overall, I think the open-to-closed is closer to 1/2 the overall travel now.

Once modified, installing the coolant lines part was fairly easy. I cut a short stretch off of the return line, and added that to the return off the heater. To that I attached the valve, minding the indicated direction of coolant flow marked on the side. Last, I connected the supply and return lines and then removed the vice grips. I am not 100% thrilled with the routing of the hoses and will incorporate a 45* angle so they are not forced so route to low. After this picture was taken, I shortened the return line another inch or so to reduce the droop a little bit. I poured a bunch of water into the coolant bottle and called it a day as it was starting to get dark.

Plenum

I returned the following morning to complete the job. In a typical install of one of these Maradyne heaters, either the purchaser connects 3" hoses to the outlets or maybe some directional vents (neither are included). Remaining a-typical, I assembled a 4 sided plenum, like the one before it, held together with the higher-end flashy ducting tape.. The top is a 13" by 5" rectangle with 1" long drop-down sides, with a 45* angled rear tail and an up-turned front (image on the right). The bottom is 13" long by 4" (with 1" drop-sides along the shorter edge) and the plenum sides are right triangles with 4" long sides. Remaining ever cost-conscious, I cut material from the old furnace intake. Recall, it was 15" square, so I cut up one side and got 13" length with 1" for the drop-sides with one cut. I taped on the top and bottom first, then the sides, and closed up all the gaps. I get this is not exactly contours-quality... this is far from that. This is all about getting on the road with whatever heat I can extract from a TDI engine. Besides, the last taped-together plenum lasted a few years and would have continued had I not torn it apart for this install.

Electrical

Before I got started on the electrical, I looked back on the post I wrote about the Vanagon rear-seat-heat fans (See Defrosting - Part 4). I discovered that the fan switch that I bought for that install was the exact same as the one that delivered with the Maradyne fans, just with a different knob. So, while I could run new wires and replace the switch, I didn't need to. So, I didn't. Instead, I cut the 3-wire plug off the fan power wires and the ring terminal, leaving enough material so I could reuse it somewhere later. I added female spade connectors to the four wires. I could easily identify the ground wire and low-fan wire so I connected those and tested the fan. Success! And even on low, this fan is more powerful than the Vanagon rear-seat-heat unit on medium. It probably rivals that unit on high, in terms of airflow, but not fan noise. This is super quiet: no fan noise, only the sounds of the rush of air.

With a multi-meter, I confirmed which of the remaining 2 disconnected wires was the wire for medium. I decided that since I had a strong 12V signal, I would reuse the relays and simply wire up the fan. This was also much easier and it insurers that the wires won't melt when I turn the fan on one of the higher settings. The air flow on the "medium" setting is considerable. Boo and I have noticed that the heat in ToyoTruck is most effective on the not-highest setting, concluding that the air speed is so high on the highest setting, it is unable to pull heat out of the heater core as it passes through. As I wired up the high fan, I considered that we could have a similar issue in Hapy now, and may really only use the lower 2 speeds. Time will tell.

Any time the coolant system is open, there are a series of engine runs or test drives followed by adding water and coolant until it levels off. Since I did not need to drive Hapy during the week following this work, I didn't run the engine. Instead, I prepared for "part 2".

The inlets for the fans are drawing outside air and the control valve is still managed by rolling under the bus. I'll get to the valve eventually, but I don't want to wait too long. The drawing outside air, however, needs to be considered right away. As it is, a drive through one of our seemingly ever-present puddles and I've got warm fog blowing up on the windscreen. At least until I route the fan inlets to the bus interior. Since wet season will persist for another few months, I got after changing the air source shortly after I completed this post. I added the image on the right here to illustrate the first problem I encountered: the return coolant line runs straight through where an air inlet would go. Of course, the support bracket isn't helping either.

Thanks, as always, for following along-

Nemo Re-Assembled

I think this will be a quick post. In my last, rather lengthy, post about Nemo, I described the effort to get him running again. Today, I cover the electrical mop-up and the other little bits to get Nemo ready for regular use... by someone. While this is barely post-worthy, the wiring fix did take me a few hours, so in a way this is just documenting how I spent a Saturday. Besides, the weather has turned too cold to spray primer or paint, so Zed sits waiting.

Car-Toys Vent

I will start with a predictable slam on the hacks at Car Toys. Recall that when they replaced Nemo's stereo, they were directly asked/told not to cut up the wiring, rather to use a pigtail. With a generic response of along the lines of "we'll do it right" wink/finger-point, they did exactly what no one wants a radio installer to do: cut wires off of a harness plug and then direct-wire a new stereo into those bare wires. So, I give them a "that's not right" glower/different-finger-gesture. All-told, they cut the 8 speaker wires, switched and steady power, ground, power antennae and illumination. The part I don't understand is why they do not have a cache of pigtails for common cars. All VW's and Audi's from, like, the mid-80's thru modern cars use the same 2 8-pin female plugs... one 8-pin plug for the speakers and one 8-pin plug for the power, illumination, etc. The corresponding male pigtails run for, like $10US on eBay, and since they plug right in, the install is faster, while also cleaner: at a workbench, the custom pigtail for the new stereo can be wired into the Audi/VW standard male pigtails. Then, you take the stereo head-unit and the cable to the car, plug in each end and you're done. Cleaner, easier, faster. Instead, Car Toys does it lazier, longer, stupider and uglier... and much harder to undo.

Stereo Wiring Un-Hack

With the center console fully opened up, I had great access to the great wire hack. I started with the speaker wires, mostly because bits of the CarToys wire-extensions (1 each purple, grey and green) were still attached to a few wires post-theft, so I could tell what they used to be used for. Once those 8 wires were sorted, the remaining wires were much easier to isolate. The only difficult pair were the switched and steady power sources, because both were plain red wires. A simple voltage test (one had 12V and one didn't while at rest) resolved that. Yes, there was a hot wire bouncing around back there. Once the pigtails were wired up, I zip tied the wires into a cable on either side of the wire butt-joints so any gentle pulling would not cause a wire joint to separate.

Climate Control and Console Re-Assembly

With the loose wires sorted, the center console already looked 100% better. I continued the re-assembly by plugging in the climate control unit. While this has 4 plugs, they are each slightly different sizes so they can only go in one way. Once plugged in, I slid the unit into place and threaded in the Torx bolts to hold it in. Then, the console cover can snap into place. 2 8mm Allen head screws later, the center console is together again. I take satisfaction in seeing the stereo plug through the hole where a stereo should be. I may pick up a cheapy clearance stereo from Crutchfield to completely close the loop... and that hole.

Kick Panel and Re-Lo

All that remained was putting the lower dash panel back on. This panel is held in place by 3 screws: one at the bottom of the fuse box frame and 2 in front of each of the driver's knees. The fuse box frame screw is easy to get to and easy to manage. The 2 in front of the driver's knees, however, require some gravity-defying. I do not know what kind of fastener was originally used; Nemo has slotted bolts. These bolts need to be balanced on the end of the driver and then tilted over about 30* to find the hole in the panel, and then the matching hole in the dash. While this is not hard, it can be frustrating. Once bolted tight, the holes are covered with small plastic bits that snap into place.

Just like that, an interior that looked like it was at a junk yard is re-assembled and looking sharp again. I juggled cars at this point, moving Nemo into a more remote spot, out from under the carport. As before, he started right up like he hadn't been un-start-able for weeks. The juggle created the space needed to get Oliver out for some Summer driving. I did discover, however, that Nemo's front passenger window I replaced also had the front window tracking mechanism damaged when the window was smashed in. So, the window does not go up and down anymore. I will need to hit the junk yard again, to source a replacement window track thing. Neat. I do like going to the junk yard, though, so maybe I'll find some other stuff we need while I'm there. In the meantime, Nemo's air conditioning blows nice and cold, so a stuck window doesn't mean discomfort.

That's it for today. Thanks, as always, for following along-

Oh, Nemo

Today's post covers my challenges with Nemo's electrical and computer system simply trying to get him to start, or maybe a signal on the OBD-2 port. The car-work hours that I did not want to spend sanding on Zed, I spent doing this... until this took over. Yeah, I know. I could use another hobby.

No Start

Like so many issues with these old cars, our challenges with Nemo started with him not starting. His battery had been sitting on a trickle charger all winter, but I had left his hood cracked to make room for the alligator clips, so this ultimately was self-inflicted. Love those. But, the path we took to get there was interesting. Nemo is sitting under the fabric carport blocking a garage door. Behind that garage door sits Oliver, the 1978 MGB convertible, that I would very much like to be road testing and otherwise driving around. So, enter my motivation for moving Nemo. Insert key, turn ignition to "RUN". I see some familiar idiot lights, including the battery, oil and check-engine. Turn to "START" and he rev'd but would not start. I went around to the tailpipe and could not smell gas, so I start with the assumption that it is fuel delivery.

Before I did anything else, I considered what I experienced when I turned the key to "RUN". I did not hear the fuel pump cycle. I did not hear the radiator fans kick on. So, something is not getting the "RUN" signal. So, I pull out the UltraGauge and plug it into the OBD-2 port. I get a never-ending "scanning..." message. Well, that's not good. I double-checked the UltraGauge in Hapy, and the computer linked within a few seconds. Okay, we have trouble with Nemo's diagnostic system which could prevent a start or we have multiple things going on. With this car, the latter is probably true. First, I tried to isolate the OBD-2 issue, and kill many many hours doing so.

OBD-2 Issue Diagnosis: General

The early B5 versions of the A4 had some interesting 1 or 2 year only issues. One of the oddities around 1997, when Nemo was sold, was the engineers choice to integrate the stock stereo with the "K-line": the signal processing wiring between the computer, many components and the OBD-2 plug. In these late 90's cars, it is the K-line you are subscribing to, not the more modern "CAN BUS". Okay, cool. There are many modules plugged into the K-line, but they are all in parallel. the diagnosis theory goes that when you get no signal on the K-line it is because one of the modules is faulting out, grounding the K-line. Once you can identify and remove the faulty module, you will get a signal on the K-line. You will probably get a failure code for that module, but you will at least get a signal. So, away we go, trying to figure out what modules are even on the K-line, and then isolating them.

OBD-2 Issue Diagnosis: Radio

The stock radio wiring was unceremoniously cut to pieces by the idiots at Car Toys when they installed an aftermarket stereo. Based on the wiring diagrams I have found and the commentary on the interwebs, I am not sure this car actually had that K-line-in-the-stereo thing. I did check the wires for the right color combinations, and for wires that were the correct colors for the K-line. I was unable to find them. There are, however, many wires sticking out of the hole where the radio used to be... before it was ripped off in Eugene. I intend to re-integrate an original plug before I put all this back together, but that's another day. I moved on to the next possible culprit: the climate control system.

OBD-2 Issue Diagnosis: Climate Control

found in climate
computer

The climate control system in these cars is another little computer. In some models, it is held in place with a couple brass clips. In Nemo, I had to remove the center console cover plate / face and found 2 Phillips screws holding it in. Once threaded out, the unit removes through the front. I unplugged the unit and checked the OBD-2 for a signal. Nope. I did, however, find a soda/beer can pull tab inside it (picture on the right, here, laying on the carpet after I removed it from inside the climate control computer thing). So, that was interesting. Next.

OBD-2 Issue Diagnosis: ABS (Brakes)

The fine folks on the interwebs have found that the ABS sometimes causes K-Line problems. The way to identify if it is the problem is to disconnect the plug. The ABS unit is on the driver (left) side, next to the washer bottle. You simply pull up on the silver metal tab and the plug lifts out of the socket. I found a piece of electrical tape floating around in there. Another question-mark from the prior owner. Neat. I checked the OBD-2 for a signal. Nope. I shot the socket and the plug with DeOxit and left it disconnected for the rest of my tests. I figured I might as well leave it better than it was (DeOxit, not leaving it unplugged). Next!

OBD-2 Issue Diagnosis: Dash Cluster

Moving on, we consider the dash cluster. The entire thing is held in by 2 Torx-head screws from the front, hidden behind a cover plate just above the steering wheel. Pull the cover plate, remove the screws and it pops right out. I unplugged the various cable plugs and checked the OBD-2 again. Nope. Grr... Next!!

OBD-2 Issue Diagnosis: ECU

example A4 ECU 

It seems like every system on the engine that has more than one wire into it delivers some signal to the computer. So, this seemed like the next logical step. I figured if I could get a signal after unplugging the small plug on the ECU, I would have shown that the issue is in the engine compartment and I could put everything in the cabin back together again. If the issue remains, then it could be the ECU. So, I disconnected the small plug from the ECU and we still didn't have a K-line signal. Grr...

So, I plugged the ECU, ABS and the dash cluster back in, turned the key to RUN and heard the click-snap of some relays firing, but no fuel pump nor fan spin. I could not remember if I heard the relays before, but this changed my thinking. If at least some of the relays are firing, then the ECU is telling them to. If there is a Check Engine Light, then the ECU must be at least partially working. Perhaps the K-line / OBD-2 issue is completely unrelated and this is just a simple fuel supply issue. So.. new plan: get the fuel pump to fire.

Fuel Pump Test

As is so often the case in laboratory settings, the pre-work for the experiment is where all the time is taken. Such is the case here. I started by removing the plate covering the fuel pump. This sits behind the rear seat in the trunk on the passenger (right) side, and is held in place with 3 very short Phillips screws. Once the plate is removed, you can see the top of the fuel pump. There are 2 fuel lines, one supply and one return, and a single electric plug. I found that slightly wiggling the plug allowed it to pull off the pump. YMMV. Once removed, you will see 4 pins. 2 of them are for the fuel level and 2 are for the pump. I started my tests with basic resistance and continuity-to-ground. Things seemed fine, so I shifted focus to test-firing the pump by applying 12V to the pump.

This is where the experiment set up took some time relative to the actual test execution. I ran a pair of wires from near the battery (not hooked up) back to the fuel pump. At the battery, I taped 10A fuse to the "red" wire and alligator-clipped the other side of the blade to the positive battery post. I alligator-clipped the "black" wire to the negative post. Back at the fuel pump, I applied the red and black wires to the fuel pump and it fired right up. I held the wires there a few second to demonstrate that it would not just run for a second and die. So, we have a good pump, but the pump won't fire from a relay signal. So, next we check the voltage from the relay, after we put the experiment wiring away.

Fuel Pump Relay Test

A4 Fuel Pump Relay

Back up front, I took a red wire, stuck it into the voltage-supply pin in the wiring plug at the fuel pump and tossed the other end through the cabin, over the outer edge of the driver seat. My plan was to compare the voltage sent to the pump at the pump. Since the relay only pops for a second when you turn on the ignition, I had to have my test equipment near the ignition key. I stuck my black lead against the metal fuse box mount, held the red lead against the wire I tossed through and turned the ignition to "RUN". I got 5V. I checked other spots around the fuse box and got 13V, so I started thinking that the relay was bad, dropping the voltage from 12/13V to 5V which, of course, is not enough to run the pump. So, I swapped out the relay... and the fuel pump still would not run. Great. I concluded that the 5V I read was actually the base charge for the fuel level sender and not the supply for running the pump. 

So, I checked the voltage at the supply-side of the relay: 13V. I jumpered across the relay pins, and the pump fired up. So, we're back to the ECU is not sending a signal. Fearing it is the ECU, I went looking for any other reason. I recalled that when Dot (the white 2000 VW Jetta 2.0 which broke the timing belt) failed, one of the theories for not starting was a crank position sensor. The thinking is that if the ECU doesn't know where in the revolution the crank is, it doesn't know when to fire, so it doesn't try. It is not as clear whether a failing crank sensor would prevent the fuel pump relay from getting a signal from the ECU, however. As much as I have tried to avoid it, it felt like I was sliding into just-swap-parts problem solving. At $35US for the least expensive part-to-swap (crank position sensors start closer to $60US), this can get needlessly expensive very quickly.

Crank Position Sensor (CKP)

A4 Crank Position Sensor

I have mentioned before my belief that the Audi engineers are sadists. Only someone who takes pleasure in other's pain could arrange for replacement items to be so hard to get to. Case-in-point: the crank position sensor. The crank runs the length of the block (obviously), so given a blank canvas, an engineer could potentially place a sensor anywhere along that axis. Chosen location? Directly under/behind the oil filter so you either have to remove the oil filter (forcing an oil change, which arguably is due) OR you need to perform contortions to get an Allen-head wrench in there. If you go this route, consider that the further the bolt comes out, the closer you get to the oil filter. At least there is only one fastener. These sensors have a long lead on them that plugs into the engine harness... behind the coolant bottle. In Nemo's case, this plug was fairly easy to get to. There are methods for testing the sensor, of course.

The Audi/VW sensor has 3 wires, from pin 1-3: power | signal | ground where the power and signal connect to the ECU and the ground finds its way to the chassis. To test, 12V and ground need to be supplied to the sensor plug (once disconnected from the harness) and a multimeter checking the signal wire for an AC wave signal while the engine is turning. No signal = bad sensor. Since no local shops had a CKP, I returned to sanding Bondo in Zed while I waited for the part to arrive.

Once I had the part in hand, I checked the resistance between the pins. I got 500ohms +/- between the middle pin and one of the outer pins. Using that as a baseline, I swapped out the CKP and then tested the one I had just removed. Same resistance. So, I concluded there was nothing wrong with the old one and put it in the stash of A4 spare parts (with the fuel pump relay).

ECU Swap

At this point, I had run completely out of ideas fo4r why the ECU was not sending a "go" signal to the fuel pump relay. I hit the local junkyard looking for a just-dropped-off A4 to scavenge the ECU. None of the A4's there had the right ECU, but I did get an ECU box cover: Nemo's had a good-sized hole in it where I thought water might have entered. Without another option, I hit eBarf and found an ECU with the same part number as the one as was currently in Nemo at a salvage yard on the East Coast (with a 30 day return policy!). Hopeful, I swapped out the ECU's which consisted of pulling out the big plugs in the back of the old and plugging them into the new one, since the box was still lid-less. I had some concern that energizing the ECU could fry it if the underlying condition still existed.

Still, I turned the key to "RUN" anyway... and heard the radiator fans and fuel pump cycle for a second before shutting off. This was how things used to work. So, I turned to start and he fired right up. I have concluded that my first guess was the correct one: I had left the hood open a little bit to make room for the alligator clips on the trickle charger, and with the hole in the ECU box lid, water got into the ECU and partly fried it. If I had not had the experience with the chipped ECU for Hapy when the computer semi-worked, I would not have been so quick to accept this. The Check Engine Light lit, so the A4 chat-boards all assume that means the ECU is fine. NOT TRUE. It could be partly damaged, like Nemo's.

The climate control is still in pieces, the lower dash panel is off, and the radio wiring, well, it's the same as it was: a mess. While I can move Nemo out of the way so Oliver can go for a spin, Nemo is not ready for driving around just yet. The re-assembly will wait, and I'll probably post on at least the re-wiring of the stereo plugs that the idiots at CarToys cut apart. I did, however, install the ECU box lid, complete with threading in the screws to hold it tightly shut. No more water getting in there.

Thanks, as always, for following along-