This page is here only to show you what kind of problems I faced with my trigger settings. The problems are solved, but there are there are some useful tips that may be useful for someone on this page. Therefore I leave it up here.

Audi 3,6 V8

Genboard v3.3

Primary trigger VR: 4 pins on the flywheel, 62* BTDC each cylinder

Secondary trigger: Hall

Config and tables in May 2006 (car not working).

Software installed:

Problem history:

February 2006

I have a feeling that the settings are still not quite right for my specs, because the

March 23, 2006

Well, it appears that the settings are not right. After enabling the secondary trigger and switching it to falling edge, we managed to get a spark and a great BANG! out of the exhaust.

But there is something very wrong with the primary trigger settings - when cranking the rpm display panics between 0-5000 rpm. When we changed the "Constant for RPM calc" to 100, it settled down a bit. But it never shows the RPM's properly. I don't know, whether the 3 additional pins are made of some kind of wrong metal or what is the problem. Anyway I think that the fact that the ECU cannot read the RPMs correctly is the basis of all my worries. Could anyone comment on this? Has anyone experienced such an RPM miscalculation?

No RPM miscalculations like this has happened. The initial value of the constant for rpm calc was correct, change it back. There must be some type of false trigg, maybe something like the problem Miska experienced with the TDC ref sensor sensing the teeth of the flywheel as well as the trigger pins. If you have a scope available it would be nice to see how the signal looks. Double check that the right sensor location is used as well! The rpm would read insanely high if the rpm sensor location was used instead of the TDC sensor location. -Jörgen

Is there a configuration guide anywhere for MegaTune? I mean something that would really help to fill the cells of the graphic tables. It is not possible to configure something when you have no idea what you're doing. I'm all out of ideas... It seems to me that the simplest (or the only) way to get the car working is to install a 60-2 missing tooth trigger wheel in the front of the engine. Then I could use Ben Nesbitt's trigger settings...

March 28: As mentioned earlier you are not looking at a problem with the trigger settings. Unfortunately the sensor seem to pick up noise from the starter gear. We have recently seen some cars running Auditrigger that has had problems with that. See: The above is not directly applicable as the Auditrigger configuration has the TDC ref sensor connected to the secondary trigger input. That means that the resistor that should be shorted to decrease the noise acceptance is R181 instead of R182.

This should fix the problem but a scope image is still helpful. -Jörgen

April 11, 2006

Yesterday I tried to get rid of the miscalculation with a new shielded cable, applied different pullups (18k, 22k, 27k,), but the ECU still could not read the rpm correctly (rpm jumped between 0 - 45 000), and flashed a red "TRIGGER ERROR" sign on MegaTune. I tried a different sensor too - the first one quit responding all of a sudden, but that did not help either. So obviously there is something wrong with the pins on the flywheel. So now I do not see any other option than to switch to a 60-2 trigger wheel...

April 12, 2006

Today I acquired a 60-2 trigger wheel which I intend to install on the front crank pulley. Please advise me whether it is necessary to position the 60-2 trigger wheel in a certain manner, eg. missing teeth and VR sensor together at #1 TDC or first tooth (or some other tooth) and VR sensor together at #1 TDC or is this even important?

The trigger problem you have experienced is very strange, it can probably be fixed with some more investigation but I understand that you don't want to pull the engine to see if something is wrong with the triggerpins in the flywheel! With 60-2 you want the first tooth after the two missing teeth to be lined up with the triggerwheel when the engine is around 60 degrees BTDC. It is VERY important that you don't have any runout when installing the triggerwheel as the different amplitude of the signals that result from that cause the noise rejection system on the trigger input to filter out the teeth which give lower amplitude. As you have already had lots of problems I suggest that you post a picture of the 60-2 triggerwheel you aquired. There are many badly designed triggerwheels out there. -Jörgen

April 13, 2006

Here is a picture of the 60-2 wheel I have:


I'm almost afraid to say this, there is only so much a person can take. But the triggerwheel in the picture is very badly designed and is unlikely to work. The missing teeth section has the same depth as the normal teeth, that usually means that you get a very high amplitude signal on the last tooth after the gap. The circuit we use to filter out noise will lock onto this higher signal and will ignore a few teeth, the software in the ECU will identify that it's a trigger error and will stop injecting and stop running the ignition until the trigger is back in sync again. Triggerwheels of this type sometimes work at low rpm but cause problems at high rpm. The cars that use triggerwheels like this has very special filter designs in the ECU that is matched to compensate for the magnetical designs shortcommings. Or as an alternative they have a very simple circuit with no noise rejection. If you look at the triggerwheels in the 034 webshop you'll see examples of well designed wheels. I have asked about well designed wheels available here in Europe but have not recived answer yet.-Jörgen

April 16, 2006

OK, then I'll give this one back and order the wheel from 034's shop. This causes no harm, but a slight time delay and I stopped counting the time months ago.:)

I will pull out the gearbox next week and try to search for the cause why the sensor cannot read the 4 pins - try whether the pins magnetize and whether the sensor is in line and in a proper distance of them. I'll do this before I place the order for a new 60-2 wheel. Maybe I don't need one after all...

April 27, 2006

I pulled out the flywheel yesterday and learned that the pins were too short - they only made it to approximately 1/4 of the VR sensor's width. So that probably explains why the VR sensor could not read the pins. I sent the flywheel to a shop for new longer pins. Let's see what happens. Live and learn...

May 04, 2006

Yesterday I reinstalled the flywheel in its place with longer and thicker pins. The pins reach almost to the other end of the VR sensor now and pass by the sensor at approximately 3/4 mm distance. I installed new shielded cable (a microphone cable actually) and placed a 22k pullup between the VR sensor's + signal wire and the - and shield on the other end. And guess what - NO DIFFERENCE WHATSOEVER! The RPM vary somewhere in the area of 45000 rpm and drop down for a tiny moment in every two rpm when the Cam Sync signal comes.

  • are you sure about 45000 ? Where are you reading 45000 RPM ? LCD ? MegaTune ? Theoretically max 25500 RPM reading is possible so anything higher suspects a MegaTune version mismatch or error-prone serial cable
  • another point of error to configure for "coiltype" trigger but drive with multitooth. The (Man)mcd dump needed so config can be checked (the config.txt above is not enough because it's theoretically possible that config.mtt was made with wrong global.h or not fully uploaded, or sg..)

Today I will have someone to measure the signals of VR and Hall sensors with an oscilloscope and see whether there is some kind of noise which confuses the ECU...

Config seems another good point to check.

Make this on your trigger page (moving anything trigger related from here along with some cleanup):

May 05,2006

I am reading this 45000 rpm from MegaTune. The cable is OK - yesterday we measured the signal and it was very stable and showed a good jump on the screen every time a pin passed the VR sensor. There is a noise in the signal, but that is like 5% of the height of the pin signal.

It would be nice to support 60-2 signal at 45000 RPM (60000000/ 45000 / 60 - 22 usec between pulses, with the multitooth detection code ;-), but I'm afraid the max RPM for a 60-2 wheel in recent firmwares (running on v3.x) is somewhat below 20000 RPM. It's very likely that it's configured for coil-type trigger, not multitooth.

A guy took the ECU to test it a little. When I get it back I'll research the software side...