Trigger setup for Audi S4, 5cyl Direct Fire engine

Audi 2,2T AAN engine

Now running with original (135-tooth + crankhome-VR + cam-HALL) trigger system

ECM: 3.3 #332

Modified to accept auditrigger

Scope messurements are done at ~200rpm

also try to take a log with distributor unplugged, you should see 0x0A for each secondary trigger

Systematic secondary trigger debug.

The LM1815 has been removed twice from this board (likely unnecessarily). I suggest not to solder back the LM1815 (or remove it if it's there or remove anything else) until the actions are planned in wiki (preferrably ask on irc to get them reviewed by someone).

Hide the solderer, or at max unsolder SJ7 if the LM1815 is on at the moment.

Visual review

I cannot spot anything suspicious:


The pad (that goes to 2nd LM1815pin3 through the rc filter) might be shorted to GND with some blob (hard to tell visually). You had the crankhome VR soldered there.

RC filter that goes to LM1815pin3

We must examine (measure DC voltage with DVM, from GND and from 5V as base) the

With the chip removed, or SJ7 unsoldered, IC3 must be pulled up to appr 4V (min 3V). This is done by 2 pullup resistors.

If IC3 voltage is less than 3V (not pulled up sufficiently),

The LM1815pin14 pulse you talked about (on irc: note that it's easy to misunderstand there) indicates that the LM1815pin3 pulse is sufficient (goes below 0V) to trigger the chip.

I find it likely that the HALL pulls the IC3 down, and therefore even when LM1815 releases pin12 output as it should, there is not voltage rise to 3V or above (to trigger the AVR input). Note that the LM1815 does not emit a positive output on pin12, just releases it (open-drain), therefore relies on external pullup. If something (like HALL input, or a solder bubble) "disables" our pullup, we cannot blame the LM1815 chip.

All sensors original except for map/iat: Bosch 0 281 002 437

Firmware 1.0.29 00:21

It turned out that the 135 tooth noise to the crankhome is inserted outside the ECM (with connector removed, it was still there), in the cable or ground.

Even if it might idle after some hacks, finally the noise from crank-VR must be eliminated, hints on InputTrigger/AudiTrigger/TestLM

It's unacceptable to use

with this setup

There is a problem under investigation: the LM1815pin3 is clamped at 0V (not at -0.3V) for some reason. Take pics, measure voltages on LM1815 pins. (supply too).

MembersPage/EmilMalmsten/AudiS/OldPage with 60-2 + camsync. Had runout and very little space to fix triggerwheel

See also