Page for the 135-tooth, 3-signal trigger system found on many 5cyl audi engines
The GenBoard/VerThree trigger hardware supports the Audi 3 input signal system since v3.3:
- VR 135 crankteeth (EC36/27 or motronic pin)
- VR crankhome 1 tooth (EC18/12 or motronic pin)
- crankhome sensor wires need to be reversed
- and cam-HALL (1 per every cam rotation). (EC36/13 or motronic pin). See cam-hall inverter.
The first successful install with this trigger-setup was done by Miska Peippo in Finland in 2005, see MembersPage/MiskaPeippo/AudiSSix.
Cam-HALL inverter
Cam-HALL signal is used to mask one of the 2 crankhome pulses.
- cam-HALL inverter is standard since 2008-06. The inverter results in small "listening window" around the 62 BTDC-cyl1 crankhome pulse. This eliminated cranking and/or 7000-9000 RPM falsetrig/triggercut experienced with some flywheel/trigger input bias combination.
- original was without cam-HALL inverter, that meant huge listening window around 134 BTDC cyl5 pulse. It was prone to noise with some installs (depending on flywheel and trigger input bias) during cranking and/or high RPM (around 7000-9000 RPM)
For [Audi 7A flywheel] that has strange notches that disturb the crankhome-VR signal, an inverter is needed to neglect the big window around 134deg BTDC cyl5 (and keep the small window around 62 BTDC cyl1).
![[Audi 7A flywheel]](http://www.theswansonfamily.us/modules/gallery2/v/marc/work_0/efiexpress/vems/crank_triggers/5cyl_flywheels/IMG_1167.JPG.html){kind=link}
- Nothing strange with theese notches. 7A flywheel is a most massive flywheel in 5cyl engine range. It has more dimension to the front. Notches allow unmount oil pan without unmount flywheel itself. Simple reason!
- What relates to Hall signal inverting - from my point of view it is step back. Audi 5cyl triggering system itself is very unreliable. Every week in our Latvian Audi forum someone stays with no spark on 10VT, 20VT or 20V engines. Normally without inverting VEMS have advantage to add some extra reliability to this unsuccessful system: it still working with dead Hall sensor. Now it is not!
- So please, developers, find a better way to get LM1815 camsync signal clean. I believe it is possible. MembersPage/GintsK
The inverter can be an NPN transistor such as TIP31
- emitter (gnd) connected to ground (EC36pin26)
- collector (output) connected to ECU cam-HALL input (EC36pin13)
- 2k7 .. max 10k pullup resistor between +5V (EC36pin28 or pin29) and NPN base
- HALL sensor output connected to NPN base.
If you have an Audi 7A flywheel, be sure to mention it to your dealer when ordering. Cam-HALL inverter is essential for 7A flywheel, and recommended for all installs.
Internal trigger hardware setup
See InputTrigger/AudiTrigger/OldHardware for older information.
v3.x since 2008-07
- the 135-tooth cranksignal is not sensitive. 18k pullup to +5V works well (primtrig LM1815 pin5 left open).
- Alternatively 2k pulldown to GND (or 1k power resistor: 1..2Watt), with primarytrigger LM1815 pin5=solderjumpered to +5V
- crankhome-VR signal processing can be configured in a few different ways. Simplest is 1k pulldown to GND and sectrig LM1815 pin5 = +5V (solder the small onboard solderblob for this)
- cam-HALL inverter is also standard now
Overview: multitooth Audi crankwheels
The old Five cylinder engines with electronically controlled ignition have 2 VR sensors and a HALL sender.
- One VR sensors sense the starter gear (135teeth for 5cyl)
- another VR sensor sense ONE pin in the flywheel located at 62deg before #1 TDC
- with 12453 firing order,this is the same as 134 BTDC cyl5
- The HALL sender is in the distributor, and the HALL trigger wheel has ONE slot acting as CAM reference. CAM ref and the Crank pin must overlap each other for the engine to start in the stock application.
These engines use a homebrew ignition module with a visible TO-3 transistor in the ignition coil console. (at least the ones I have seen) Igniton computer is made by Hitachi (MAC-xx).
The small spacing between the teeth (together with cambelt sloppyness) makes it impossible (at least without very advanced, long-term filtering) to sync the engine without the pin in the flywheel.
Signal timing graph from 5-cylinder MC-engine:
The same type of triggersystem is used on many older Audis, even the Audi V8 had it until it was replaced with the A8. The engines with an even number of cylinders has an 136teeth flywheel to make everything add up.
Solution:
The cam-HALL pulse (0 volt) masks out the 62deg BTDC cyl1 crankhome pulse, but (high level, usually 3.3 .. +5V) leaves the 134deg BTDC cyl5 pulse reach the processor. (just the other way around with the cam-HALL inverter)
This way the processed "cramhome" signal is timed from crank, but only 1 pulse for each cam-rotation''' (suitable for 5cyl ign). Effectively a 'cam ref signal' with no slop at all.
135 interrupts per crank-rotation still needed, but the interrupt code is shorter than for 60-2 wheels, allowing 9000+ RPM.
Above 9000 RPM most users apply 10+1 InputTrigger/MultiToothNoneMissing (5 evenly positioned crankpulse and 1 campulse). 15-1 style missing tooth crankwheel was also successfully used, but 5 evenly positioned crankpulse is simpler. The only disadvantage of 5*72 degree crankwheel is that camHALL chosen edge must clear the crankpulse even with the worst case of cambelt sloppiness (ideally midway between the neighbor crankpulses, 36 degrees from each). With 15-1 wheel just make sure campulse stays away from the tooth after the missing cranktooth.
How to connect the 3 trigger signals
- EC36pin27 - Primary trigger 135 cranktooth VR. Usually no problem
- EC36pin13 Sec.trig cam-HALL 1 window camtooth. Best to verify with scope or soundcard (or at least visually) that the cranhome-VR is around the middle of the cam-HALL window. Essential to verify after adjusting the cam-window
- don't forget to apply supply voltage for your HALL sensor
- EC18pin12 - crankhome VR (1 tooth per crank)
- originally 10..12k pullup to 5V on crankhome VR signal recommendation was changed to "1k pulldown to GND", see above
- C40=1uF populated since ages (don't worry about it)
- Important It is necessary to reverse crankhome polarity at the crankhome connection on the firewall (engine bay side), using 3 pieces of wire, 3pin JPT Male and Female connector is needed to make this properly. A good signal looks like [this] at EC18 Pin 12
![[this]](http://linkopingsmotorsport.se/1029/g4_pin1.gif){kind=link}
Don't forget to use shielded cables, separate for all 3 signals. The shield only connected at the ECM end. "return" is to GND (sensor ground), not GND5. See MembersPage/PhatBob/UserGuide.
See InputTrigger/AudiTrigger/TestLM to see how the first installs got sorted out. Old method, likely will not work with 1.1.x, should not be needed anyway:
- Note the Manmdd0c TerminalProgram command. After this command:
- capture output (start log; crank for 5 seconds, but don't cut ECM supply as you'll have to issue Manmdd0c again)
- Upload the mdd0c_trigger.log file (see file-aree on DocsPage bottom)
- and publish the link on your MembersPage, so it can be analized (looking for trigger malfunction) if
Signal Sloppyness - info for advanced users. Safe to skip
The sloppiness seems small, see [image1] and [image2]. Our implementation accepts if the "cramhome" (== crank-cam hybrid) pulse comes normally, or one tooth too early (which should be rare, but possible if the VR sensor is not aligned properly).
![[image2]](http://www.sjmautotechnik.com/trouble_shooting/wave/RPMTDCId.jpg){kind=link}
If the crank-home is sloppy, not always between 2 given crankteeth, the code will finally sync as if the crank-home always came after the tooth coming later.
Example
Here we name 3 given teeth A,B,C. If crankhome is seen
- always after B: this is the normal setup, this should theoretically be the only possibility if the VR sensor mechanical install is fine. trigger_tooth=00 means timing from B.
- mostly after B, but sometimes after A: this (though it should be unlikely) is tolerated, timing from B
- mostly after A, but sometimes after B: timing from B, but initially (while crankhome is coming after A) timing from A might happen !!
- sometimes A, sometimes B, sometimes C: forget it. In fact this (>2.67 degrees sloppyness and unfortunate position) should really never happen (unless you hold the VR sensor in your hand while running the engine ;-) : remember that crankhome is timed from crank
- no more possibilities
HISTORICAL configuration for 1.0.x (for 1.1.23+ is the official branch for auditrigger now, this is obsolete)
- the 5cyl InputTrigger/AudiTrigger engine will need 1.0.29 +firmware (see GenBoard/UnderDevelopment/FirmwareChanges)
- MegaTune r027 or later will be needed (r028 should work too)
We must start from a coiltype + camsync setup (maybe like MembersPage/MichaelRichards/Projects/NicksGTX or [Fero]
- secondary_trigger=1D is standard (rising edge, camsync with filtering) Michael Richards and Fero use this
- secondary_trigger=19 (rising edge, camsync without filtering) could work too (or even better ?). But secondary_trigger=09 cannot work.
- don't forget the reset_engphase_after and tooth_twidth.. variables!)
- primary_trigger=FB # rising edge, coiltype (yes!), trigger filter disabled (bit2=0)
- very important, that coiltype chosen, and primary trigger filter MUST be disabled
- tooth_wheel=87 # decimal 135
- recommended trigger_tooth=1B is actually appr. 27.8 toothtimes after secondary trigger (assuming first crankpulse comes 0.8 toothtime after "cramhome") pulse
- ignchmax=04 # 5 cyl
- alternate=14 # or 04 if no simultaneous injection is needed at startup
- ign_tdcdelay=78 # = decimal 120 = 60 degrees
- together with our trigger_tooth setting, cramhome is assumed to be 60 + 27.8 * 360/135 = 134 crandegree before cyl5 TDC (standard setup)
- h[0]=08 02 01 04 10 00 00 00
- assuming 53124 fire order,
- and direct mapping injchannels A,B,C,D,E (hexadecimal 01,02,04,08,10)
- remember that hexadecimal 10 (last active element) == decimal 16 (if using MegaTune)
- another_trigger_tooth=36 # decimal 54
- trigger_tooth=1B # tooth "27". For auditrigger in 1.0.x, tooth_cnt counts from (another_trigger_tooth-1) down to 0. So beware that lower trigger_tooth value uses a later tooth as the "trigger tooth"
- h[2]=40 10 00 20 60 00 00 00
- assuming 53124 fire order.
- Remember to change h[2] if you use a different output mapping for ignition channels (like the not standard 00..04 mapped to cyl 1..5)
Auditrigger 135 tooth config for 1.1.22+ :
http://vems.hu/download/v3/firmware/v3_firmware_1.1.22.zip\nÿ1ÿ
- Reftooth array (decimal 0, 18, 36, 54, 72 but traversed backwards). You can rotate reftooth array, if you rotate h[2] ign-out sequence, the only effect is initial syncup freq. Starting with 00 gives the fastest startup.
- h[1]=00 48 36 24 12 00 00 00
- for cyl order 5,3,1,2,4 (ignchannels 4,2,0,1,3 in Miska's wiring, this is NOT the recommended way)
- h[2]=40 30 10 00 20 00 00 00
- with the recommended wiring, outputs are fired in sequence (either up or down: this looks good on LEDs and more importantly damn easy to verify the order correctness in MegaTune without thinking, after, say a rotation attempt), in this case ignch6, ignch2, ignch1, igch0, ignch7 (and coils are wired appropriately to cyl1,2,4,5,3)
- h[2]=60 70 00 10 20 30 40 50
Find full config and trigger-extract at:
http://vems.hu/files/MembersPage/MarcellGal/Audi/etc/
Only get information for starting, tune your engine
Other Audi triggers:
There is also an other audi trigger arrangement on the older audis that don't have a knock sensing ignition. They only have a 5 slot trigger wheel in the distributor and no crank trigger and a hall sender controlling a auto dwell ignition module. If a few degrees of ignition inaccuracy is acceptable one of these distributors can replace the entire ignition system on the computer controlled cars.
The later models have a standard Motronic triggerwheel and a CAM sync sensor.
See also:
- VemsAudiAan - the trigger related config is easier from VemsTune
- InputTrigger/AudiTrigger/OtherToothWheel - less common 130, 136, 132 ... tooth crankwheels in other engines
- InputTrigger
- http://www.lanzo.se/auto/audi.html an interesting story about mechanical issues
- MembersPage/KristsMezgals
- InputTrigger/AudiTrigger/OldCircuit the old circuit that was eliminated by firmware code
- InputTrigger/AudiTrigger/TestLM1815 - some guys got problems with VR input for secondary, here is instructions how to test it and write report