The stage is small but the audience is great.

South African T3 / T25 Microbus, post 1991

The Volksiebus is a special version of the South African Microbus. It was introduced in October 1995 and was available with the 5 cylinder Audi 2.3i 90kW (AFU) engine as well as the 1800 Golf engine (which at one stage powered something like eighteen different vehicles available from VWSA at the same time).

2.6i Microbus Vehicle Specifications

http://www.lekkercamper.co.za/travel-article/south-african-vw-t3-big-window-big-personality.html

http://www.partsource.co.za/Specialists/pasMMDetails.php?CODE=64083699

Production Figures

 199419951996199719981999200020012002
VW T3 Microbus & Caravelle 2.5i 1991 - 1995324732       
VW T3 Microbus & Caravelle 2.6i 1994 - 199610254736N/A      
VW T3 Microbus & Caravelle Exclusiv 2.6i 1997 - 2002   N/AN/A734N/AN/AN/A
VW T3 Volksiebus 1.8 1994 - 1999N/A1635N/A2631921316   
VW T3 Volksiebus 2.3i 1995 - 2002 963N/AN/AN/A1316N/AN/AN/A
VW T3 Panel Van 1.8 1995 - 1998 343823012    
http://www.easyinfo.co.za/htm/custom/lsaker/vwcars/bus.htm

This one's a 1996 model (the 2.3 and 2.6 engines were introduced in 1995). We've had it since 2000.

VIN plate AAVZZZ25ZTU001013

Engine Number AFU001109

90kW 2.3i "AFU" engine

AAY - 2.5i - 100kW
ADV - 2.6i - 100kW
AFU - 2.3i - 90kW

http://www.brick-yard.co.uk/forum/power-figures-on-the-za-engines_topic61580.html

2.3 is 122 bhp (90 Kw) & 185Nm 2.5 & 2.6 are the same at 136 bhp (100 Kw) & 200 Nm The 2.6's get max torque at 3000 rpm & the 2.5's are at 3500 rpm.

http://www.syncrosa.co.za/forum/showthread.php?tid=1514, The 2.6 has a stroke of 95.5 and bore of 82.5, which gives 2 553cc. Compression ratio is 10:1.

According to Audizine the 5 cylinder engines weigh about 185 kg.


Gearbox / Transmission

These vehicles were fitted with either a 4-speed or a 5-speed gearbox. The top gear (4th or 5th) ratios are the same (0.85) and the differentials are the same too -- so the five speed box won't make you go any faster. The first gear on the 5 speed box is a bit more powerful, and of course you get more options (I find that 3rd is sometimes too strong up a hill while 4th is not strong enough, with the 4-speed box).


Tyre size and pressure

Tyre pressure plate

Our Kombi came with 185R14C tyres (80 profile) but we're now running 195R14Cs.

Size DiameterCircumferenceRevolutions
185R14C 652 2047489/km
205/65R15648 2035491/km
195R14C 668 2098477/km

Fluid Capacities

Engine4.5 litres 20W50
Fuel tank85 litres
Cooling system17.5 litres, 20% G12 coolant
Gearbox3 litres

The sump plug takes a 14 mm copper washer.

Battery

Standard battery is a 647 but these days they recommend a 651C. More capacity at about the same cost.


From Microbus Wiring 5.pdf Fuse Panel layout from _Microbus Wiring 5.pdf_
Relays

 1 - Main Relay (53)
 2 - Rear Wash / Wipe (not fitted)
 3 - Not used
 4 - X-relief relay* (18)
 5 - Coolant shortage / temperature switch unit (42)
 6 - Hazard light relay (21)

 7 - Radiator fan 1st stage (53)
 8 - Intermittent wash / wipe (19)
     (not fitted - bar between pins 4 and 5)
 9 - Not used
10 - Not used
11 - Single tone horn relay (53)
     (not fitted - bar between pins 2 and 4)
12 - Not used

13 - Thermo-fuse, 20A, central locking (not fitted)
14 - Fuse, 20A, main beam headlights
15 - Fuse, 10A, instrument lights
16 - Fuse, 30A, radiator fan

17 - Fuel pump relay (53)
18 - Main beam headlight (53)
20 - Fuel gauge damper module
* The X-relief relay cuts all non-essential circuits while the engine is cranking.
My fuse panel
(Not all the original fuses, doesn't quite match the paperwork)

The fuse cover sticker is... not quite right. It doesn't mention the fuses for the fuel injection system.
fusebox sticker
110A (red)Low beam left
210A (red)Low beam right
310A (red)Number plate light
415A (blue)Rear wipe wash
515A (blue)Winscreen wipers and washer
630A (green)Radiator fan and fresh air blower
710A (red)Park lights right
810A (red)Park lights left
920A (yellow)Mirrors and rear window defrost
1015A (blue)Spare
1110A (red)High beam left
1210A (red)High beam right and spot lights
1310A (red)Hooter
1415A (blue)Reverse lights
1510A (red)Spare Circulating pump relay
1615A (blue)Fuel gauge damper, glove box light
1710A (red)Turn signals and warning lights
1820A (yellow)Spare Fuel pump and Motronic unit
1930A (green)Spare Central injector valve, air control valve, motronic unit and fuel pump relay
2010A (red)Interior lights, brake lights
2115A (blue)Radio, clock
2210A (red)Cigarette lighter


Quiescent power drain

I had problems with the battery running flat. Turned out to be the aftermarket radio / PA system my father had installed. But for the record.

Motronic control unit600uA
LCD Clock2.4 mA
Immobiliser4.2mA / ~7mA when LED flashes


Setting the timing

It's best to get all the basics right. Your bus most likely had a Dreaded Previous Owner, which means a lot of things could be different from what one might expect. The timing belt might even be off by a tooth or two, I've been told.

1. Distributor. Trace the #1 plug wire to the distributor cap, it should be towards the back (you're standing at the back. This is a VW. Front is front) of the distributor and slightly down from centre. But remember the DPO, the distributor could be fitted any way around.

2. Timing marks. There's a line on the back of the camshaft pulley that aligns with the top of the block for TDC. Pull the #1 plug, get a sosatie stick or something, and position the piston at the top of its stroke with the rotor pointing roughly at where #1 cylinder is on the distributor cap. You should be able to see the little line on the back of the camshaft pulley (where the back of the pulley is towards the front of the vehicle). If the line's not matching piston #1's TDC, your timing belt might be on wrong.

Now check whether you can see the TDC timing mark on the crankshaft pulley. Look through the hole behind the number plate. You will most likely need to clean things up a bit, use tip-ex or something to highlight the mark. They say that the pulley has a rubber bushing and that the whole thing can slip so that your TDC mark is no longer at TDC, in which case you would need to make your own marks, or fix the pulley.

With a 135mm pulley diameter, six degrees BTDC is 7mm on the circumference, so make a second mark 7mm to the right of TDC. I have one of those timing lights where I can set the advance on the light but I don't trust the damn thing.

To set the timing, you need to bridge pins 2 and 4 on the Diagnostic Plug. Rev to 2000 rpm and set the timing to 6 degrees BTDC. Microbus Timing.pdf, extract from Owner's Manual, http://vwclub.co.za/forum/viewtopic.php?t=46087.

Replacement Distributor

Goldwagen will sell you a brand new distributor. "WAG Original Spare Parts" nogal. Their part number is A4671. Cost R635 in May 2017.

This thing won't work. Can't work, as a matter of fact. Here's why and how to fix it.

This is the original VW distributor (0 237 522 015, 034 905 205h). They were nice and put a mark where cylinder #1 is (this lines up with the distributor cap).

Note the Hall Effect Sensor and the interruptor plate. Note the #1 mark. Note the position of the rotor. The distributor turns clockwise, and as the interruptor plate enters the Hall Effect Sensor the coil fires and HT goes via the center pin on the distributor cap via the rotor to cylinder 1.

All fair and well.

Here's the WAG replacement. They moved the Hall Effect Sensor to the other side, to save some money. It's actually a good idea, the original placement of the Hall Effect Sensor dates from when distributors had a mechanical advance.

Unfortunately they didn't change the position of the slots in the interruptor plate. It's kind of tricky to see on the photograph, but you can check it out on the real thing (because maybe by the time you buy one they've fixed it). You need to mark cylinder #1 yourself, fit the cap and trace a line down from the tower, mark the body with a koki, turn the rotor and look at the interruptor plate. In my photograph you will see that the slot (OK, it would have been better if I'd put the rotor on, but you can trust me on this) is just starting to point at #1, while the interruptor place is fully inside the Hall Effect Sensor.

I thought maybe their Hall Effect Sensor inverts the signal, but I checked, it doesn't.

It is possible to drive out the pin at the bottom, remove the distributor shaft, use a hydraulic press to press the interruptor plate off the shaft, turn the plate 36 degrees or so (mark 1 eyeball required) and put the whole thing back together again. And it works.


Coolant System

Annotated cooland system diagram

Coolant flow when the thermostat is open. With the thermostat closed there will still be circulation through the heater core and oil cooler but not through the radiator.

The picture below is from https://www.vwclub.co.za/forum/viewtopic.php?t=71913. Note that the flow direction is in fact the opposite from that shown here.

See also https://volkswagen.7zap.com/en/za/transporter/tr/1999-230/1/121-121060/.

Temperature Gauge and Low Coolant Warning

My temperature gauge red LED wasn't working. While fixing it I took some notes.

The first function of the blinky light is to draw your attention to a pegged needle. The gauge contains a bi-metal strip with a resistive element coiled around it, as it heats up the bi-metal strip bends and the needle moves. The one side of the heating element goes to the regulated 10V, the other side to the temperature sender unit which is just a variable resistance -- 100 ohm for cold to normal, 33 ohms for kind of hot (approximately).

schematic of blinky light

R2 and R3 are 2% precision resistors, I'm not sure I read their values right -- I think 10 720 and 11 520 ohm for 4.8V? Anyhow, they form a resistive divider which puts a reference voltage on the opamp negative input. The positive input goes to the gauge input via the diode, and then there's also the RC circuit to consider.

On startup, the capacitor is discharged so the positive input is at 0, which is lower than the negative input, so the opamp output will be low, turning the LED on (it's a self-blinking LED, there's a little blinker IC inside the LED package). The capacitor now charges up to half of the supply voltage (because of the two 750k resistors) and that's higher than the reference voltage, turning the LED off. With the LED off (and in isolation, i.e. nothing connected to the G terminal) the voltage on the capacitor will now rise to the supply voltage, but of course because of the temperature sender, in practice this will be whatever the gauge / sender combination is doing plus 0.6V for the diode drop.

If the coolant gets hot, the diode will pull the positive input down and the LED will start flashing.

I don't think D2 is really needed. Unlike a relay, the LED won't have an inductive kick. Maybe the idea is to discharge C1 through R4 when the ignition is turned off, but this would still happen through R1 so that doesn't seem likely. Maybe it just seemed like a good idea at the time.

Then comes the more clever bit. Assuming that this gauge is already fitted to your line of vehicles. And let's say you also want the LED to blink when the coolant runs low.

The first solution was for the low coolant sensor to just pull the gauge line low. This pegs the temperature meter and blinks the LED. But it also scares people into thinking their engine overheated when it didn't. So the engineers got clever with the Coolant Level Warning Lamp Control Module. When it senses that the coolant is low, it puts a short pulse (5ms three times a second, give or take) on the analogue gauge line. This is too short to affect the heating of the bi-metallic strip by much, so the needle stays pretty much in the same place. But it's enough to discharge C1 via D3 and... blinky light.

Sensor check

Turn on the ignition. The red LED on the temperature gauge should blink about a dozen times, then turn off. If it doesn't blink, it's broken, fix it.

Now, unplug the water level sender on top of the expansion tank on the right-hand side of the engine bay. Around twenty seconds later, the LED on the temperature gauge should start blinking again. If it doesn't, your #42 Coolant Level Warning Lamp Control Module is broken. The 42 is a latching system, so after plugging the sender back in you will need to turn the ignition off and then on again to stop the LED blinking.

Auxiliary Water Pump

I believe that the engineers over at VW had a reason for everything they bolted to the engine. It cost them money, which could have been profit had that part not been essential. Only hacks remove parts and call ita feature. Of course, our kombi had had a hack-mechanic in its past, who removed not only the pump but also the relay that drives it.

When the engine is hot and you turn it off, the water in the head can start boiling because of the latent heat in the engine, This is not good for the system as a whole, and apparently caused head failures before they added this pump, which circulates water for a while after you shut the engine off.

I bought a new pump and installed it. I also reverse engineered the relay that drives it (J151, controlled by temperature switch F95).

As far as I know the correct part number for this pump is 034 965 561C. It's similar to 251 965 561B (Bosch Auxiliary Water Pump for Volkswagen VR6 Motors found in the Volkswagen Corrado, Passat, Jetta, Golf / GTI, and Eurovan) and 078 965 561 (Golf IV 1.8T and Audi 2.7T). 1K0 965 561J (Auxiliary Water Pump for Tiguan Passat Jetta Golf CC GIt Audi A3 TT Q3) might also work. After all, it's only a pump.

I then found more signs of a hack-mechanic. On the cylinder head water flange there are two temperature sensors. The top one is 357 919 501A, 4 pin, yellow, dual temperature gauge sender, G27 on the wiring diagram. The one side goes to the ECU and the other side to the temperature gauge on the dashboard. The bottom one (F95) in my case was 357 919 501 -- the exact same thing. This is not right. It should be a combined temperature gauge sender (which is not connected to anything) and thermal switch (which comes on at 105 degrees C and is connected to the relay J151).

Some searching (Hella Technical Information) lead me to suspect that the part number for the thermal switch might be 701 919 369B or C. Goldwagen's system crosses this to 357 919 501 i.e. the top sensor, and that's obviously not right. The internet crosses it to a bunch of stuff which I ran past the staff at Goldwagen, finding the Topran 104 109 755 (which is sort of the correct thing but with the wrong pinout -- the thermistor is connected where the switch should be and vice versa) and the Meyle 100 800 9058 (their part number A5366) which has the correct pinout but switches in at 95C instead of 105C. This means the Auxiliary Water Pump will run more often, and I'm cool with that.


Radiator Fan

The radiator fan (V7) can run at one of three speeds. Four, if you count "off".

([383] is power when the air conditioner is on. [389] is power when the aircon gas is hot)

In the wiring diagram you will also find two resistors marked N81. These control the speed of the air circulation fans. They have three sections of 0.4 ohm, 0.85 ohm and 2 ohm respectively, while N39 has two sections of 0.09 ohm and 0.28 ohm. They might look somewhat similar but they are not interchangeable.


Throttle Valve Potentiometer 044 907 385A (G69)

This is a Golf part that's also used in a number of other models, Audi, Seat, etc.

(pics from http://forum.club8090.co.uk/viewtopic.php?f=12&t=83127)

Masterparts equivalent Meat & Doria 83086


Nothing from here on down is gospel. I'm also not too sure of anything above...
ETKA Engine, Electrical.
G16 Ignition module 0 261 230 008 (VW 237 906 311 1 ?) (3A0 906 051)
Courtesy switch http://www.t4srus.co.uk/vw-t4-courtesy-light-door-contact-switch-years-90---03-7d0947563a-2316-p.asp door switch two pole 113 947 561H http://www.alanhschofield.com/ourparts/prod_3804580-Interior-Light-Switch-6879-113947561H.html

ECU

From http://www.brick-yard.co.uk/forum/wiring-diagrams-or-manuals_topic66993.html

[...]there was an ecu change mid-1997 and again from 1998 onwards, but maybe only remapped for unleaded fuel, judging by the ETKA comments.

For 2.6: 
early version 22S 906 022,  
10/95 to 12/97 22S 907 404 B, 
1/98 onwards 22S 907 404 D

For 2.3: 
22S 907 404 (Volksie only), later suffix A or C, same dates for changeover.

Also, https://volkswagen.7zap.com/en/za/typ+2/t2/2003-275/9/906-906010/

22S 906 022  2.6  to 09/95
22S 907 404B 2.6  10/95 - 12/97
22S 907 404D 2.6  01/98 -

22S 907 404  2.3  Volksiebus 10/95 - 12/97
22S 907 404A 2.3  ?
22S 907 404C 2.3  01/98 -
As I understand it, in 1998 they changed the system to use MPI (individually driven injectors) and this is the "Metal Rail" fuel rail and the -C and -D suffix ECUs. 22S 906 022 and 22S 907 404, -A and -B would be single injector drive "plastic rail" (there are still five injectors). Here's a picture of a late-model engine bay with MPI.

22S 907 404A 2.322S 907 404B 2.6
The EPROM is a 27512-equivalent 64k x 8 device.
2227355853
0261204028
This EPROM contains the following identifying strings:
0261204028
26ZA0002
22S907404A
0261204027
MAY 1995
0261204028
2227355853
M15 004
166   355 914
26ZA03   BF8B
This EPROM contains the following identifying strings:
0261204166
26ZA0003
22S907404B
0261204165
SEP 1995
0261204166
2537355914
M15 004

From http://vwclub.co.za/forum/viewtopic.php?t=46087

It is a bosch motronic unit. 
It has a singel feul rail that will pulse all at once per fire point [5 cyl] 
as per panic.It has a idel steppe motor 1xt.b sensor ,water temp , air temp and manifold sensor. 

How to adjust system. 
1x adapter cable from vag plug to the 5pin plug in the picture as seen. 
To get into the ecu the ign must be switched on 
Enter ecu [01] then go adaption [10] enter channel 01 
Start bus [make sure battery stong or it will kick you out] 
Adjust the value in channel 01 up or doun [up richer lower leaner] 

Apparently these ECUs use the KW1281 protocol.


Cambelt http://www.brick-yard.co.uk/forum/cambelt-tensioner_topic70736.html I used this - http://www.audiworld.com/tech/eng102.shtml for reference when I fitted new belt,idler,waterpump and crank/cam seals, note - the crank holding tool 2084 is essential - I had one made
The clutch parts are specific to the South African T3s, an Audi 240mm clutch with 24 splines will fit eg LUK 624083900 (Audi 200 2.1) but on the original clutch friction plate the centre boss is offset towards the gearbox - this means that the LUK kit (or other off the shelf clutches) will not fully engage on the input shaft splines. I think many people use the Audi clutch kit with no problems, I had my original clutch refurbished but don't know if that route is open to you. http://www.brick-yard.co.uk/forum/overhaul-parts-needed_topic92302_page2.html

[Image] Hit Count hits since 2017-05-04.

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