Author Topic: Serious triggering errors  (Read 23907 times)

Offline sink

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Re: Serious triggering errors
« Reply #15 on: March 21, 2011, 03:05:14 pm »
Would You or someone explain to me the logic behind the first trigger tooth and next trigger tooth.
I have trouble understanding, if TDC after the trigger is 72 degrees, first trigger tooth 8 and next trigger tooth 18 - How does this work?
To me it seems to be 10 degrees between first trigger and next (18-8=10) but the next after that is already 18 degrees and the next after that also 18??? Yes I've gotten very mixed-up :(

Offline mattias

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Re: Serious triggering errors
« Reply #16 on: March 21, 2011, 03:54:00 pm »
Som basics first :
Like I said earlier, every tooth is 8 degrees wide with this trigger type. (360 degrees, 135 teeth on flywheel, divided by 3).
Next trigger tooth is the distance between cylinder events, counted in number of teeth.  In number of degrees it's 720 degrees / 5 cyls =  144, and is easily verified since 18 teeth x 8 degrees = 144 degrees.

With the case of a "simple" trigger like this, the cam sync tells the ECU to reset the trigger tooth counter which syncs up the ECU with the 4-stroke cycle. After cam sync it begins by waiting for the "first trigger tooth" and then uses the reference tooth table to identify each cylinder event.

After seeing the cam sync signal, it will wait "tooth width" degrees x "first trigger tooth", in your case  = 0 since you should be using "first trigger tooth" = 0, not 8x8 = 64 degrees after cam sync signal.
The "TDC after the trigger" tells it exactly how many degrees until each cylinder reaches TDC from it's corresponding reference tooth. It's desireable to keep this number at least 10 degrees above the highest advance your engine will be using to give a margin for calculations, there are even exceptions depending on trigger type.
First trigger tooth is tooth "0" in the reference table, and is the start of the ignition firing order - which doesn't need to begin with cyl 1, the ignition output table can be shifted in order depending on when the signals mechanically must occur.

Depending on the type of primary trigger the cam sync pulse is handled differently, I won't explain the details of all the ways it can work -  all you as the user has to worry about is to strobe cyl 1 and identify where in the ignition order it is located. Especially with modern engines it can really be hard to see this since there are so few markings and if you're far off you can't really tell anything, like with the Audi 5 cyl. Even worse is when the markings are not even at TDC like the Volvo 5 cyls, those marks are only used to align crank and cams when assembling the engine. In such cases the best thing is to make your own TDC markings.

Offline sink

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Re: Serious triggering errors
« Reply #17 on: March 21, 2011, 06:35:51 pm »
Can this be caused by the distributor not beeing in it's correct position - like half a turn?

Offline mattias

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Re: Serious triggering errors
« Reply #18 on: March 21, 2011, 11:45:46 pm »
That would definately be a possibility!
The engine should still run just fine but with different ignition output table and primary trigger settings. Obviously doing it the right way is preferable..

If it is so, then it would mask out the home tooth on the wrong rotation of the crank, causing you to have a very different ignition order since the cam will be half a turn "wrong" when the cam sync pulse occurs. Events happen at 0, 144, 288, 432 and 576 degrees. If you add 360 degrees to that you'll shift events, and they won't have the same offset to the cam sync as the "normal" signal.

« Last Edit: March 21, 2011, 11:49:34 pm by mattias »

Offline sink

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Re: Serious triggering errors
« Reply #19 on: March 22, 2011, 12:53:38 am »

Well now this sounds like my problem. If You checked my config (yes?/no?) then You should see that my ignition and injector outputs also primary trigger settings aren't in that order as people using VEMS on Audis are used to see them. 

Well, well, well... will have a look at that first thing tomorrow :)
« Last Edit: March 22, 2011, 01:09:19 am by mattias »

Offline sink

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Re: Serious triggering errors
« Reply #20 on: March 22, 2011, 02:52:09 pm »
Now this is getting more and more confusing more me :S

First of all I rechecked the engine today, everything - the camshafts, flywheel and distributor were all aligned as they should be. Then I turned the distributor 180 degrees and guess what - no more trigger or secondary trigger errors. But now the distributor isn't alligned with it's markings - well okay, that shouldn't be that important. But as Mattias has mentioned before - if the Hall sensor isn't in place then the engine would work but just with other ignition outputs and trigger settings. But I ONLY rotated my distributor and tried to start the engine and it did fire up - it ran very very rich and also it kinda misfired :S I think there's something wrong with my settings

Also did a short log of the car trying to idle http://uploading.com/files/b5b6aa36/v3.3_n000620-2011.03.22-12.27.48.vemslog/

These are my current primary trigger settings


This is my current ignition outputs table


This is my current injector group table


What should I change, what's wrong?

Or can anybody give me a good base config from where I can start working off, all the right trigger, injector and ignition setting already in place.

Offline mattias

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Re: Serious triggering errors
« Reply #21 on: March 22, 2011, 06:07:51 pm »
Get a strobe light set up on cyl 1 coil,  since you've done this before you probably have already made a temporary adapter between coil and spark plug for the pickup.

Just changing trigger settings like that without using a strobe light first to verify is playing a game of chance.

Offline Erikk

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Re: Serious triggering errors
« Reply #22 on: March 22, 2011, 06:26:59 pm »
But I ONLY rotated my distributor and tried to start the engine and it did fire up - it ran very very rich and also it kinda misfired :S I think there's something wrong with my settings

Also did a short log of the car trying to idle http://uploading.com/files/b5b6aa36/v3.3_n000620-2011.03.22-12.27.48.vemslog/

Or can anybody give me a good base config from where I can start working off, all the right trigger, injector and ignition setting already in place.

Are you sure you are running very rich? You are only using 1,0 - 1,2ms Pulsewidth in the datalog.
Not even the sloppy 1680cc´s uses that low PW at ~1800rpm.


Heres an 3b Audi I did last year: http://www.vems.hu/files/ErikEnglund/Configs/v3.3_n002155-2010.09.29-20.39.54.zip
« Last Edit: March 22, 2011, 06:33:20 pm by Erikk »
Sweden - erik.englund@gmail.com

Offline sink

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Re: Serious triggering errors
« Reply #23 on: March 22, 2011, 06:36:50 pm »


Well lambda was fluctuateing between 0.7....0.8 It should be seen in the log. (Also I could feel it in my eyes that it was rich - they started to water after running the car for about a minute.)

I'll get the srobe light back and will start thinking hard near the car  :)
« Last Edit: March 23, 2011, 01:44:33 am by mattias »

Offline Erikk

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Re: Serious triggering errors
« Reply #24 on: March 22, 2011, 10:29:47 pm »


Did you upload the correct logfile ? It seems to me like the engine barely has any fuel at all.
« Last Edit: March 23, 2011, 01:44:46 am by mattias »
Sweden - erik.englund@gmail.com

Offline sink

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Re: Serious triggering errors
« Reply #25 on: March 23, 2011, 12:12:26 am »
What the "F" IT is lean ??? When I was in the garage a friend poked around in my Vemstune and when I got back behind the computer every gauge on the display was missing besides the sec trigger one :D So I only glimpsed on the lcd display, seems that I made it up in my mind  :-\

And because I was at work from then til now I didn't have the chance to look it over again myself, my apologies :(

Erikk the config that You shared - is it from an original 3B - meaning the ignition is still divided by the distributor? At least it seemed so to me.

And I'll stay quiet for a few days now til I get things more sorted out.

But still a very big "thank you" to you all for helping so far :)

Offline Erikk

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Re: Serious triggering errors
« Reply #26 on: March 23, 2011, 11:34:41 am »
Erikk the config that You shared - is it from an original 3B - meaning the ignition is still divided by the distributor? At least it seemed so to me.

Yes, that config is for distributor-ignition, so dont use it straight out of the box.
Sweden - erik.englund@gmail.com

Offline sink

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Re: Serious triggering errors
« Reply #27 on: March 23, 2011, 01:52:22 pm »
I actually asked for another config to see how other cars have set up their trigger setting and ignition outputs  :)

So I had a go in the garage again today, seems that I might "get there" :D Just have to get a working strobe light for next time and set up the fireing order how the mechanics want it - like Mattias told me to do.

Am I right by saying that the fireing order on 3B, 7A and AAN engines is 1-2-4-5-3?

Offline sink

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Re: Serious triggering errors
« Reply #28 on: March 27, 2011, 12:49:32 pm »
So I got the car running finally without any errors :-) Also I now know why the log showed that the car was running lean but why I thought it was running rich. This was because the IAC was stuck in it's fully opened position. I disconnected the IAC valve and the car started to run normal :-)

The thing to my triggering error lied in the distributor, seems that now it is in it's working position. Also then I had to rearrange the ignition outputs because the fireing order then didn't line up with the engine's working order. As this engines fireing order is 1-2-4-5-3 I had to arrange the ignition outputs in byone step 2-4-5-3-1
Now the engine works nicely  ;)

But NOW I can't get the injectors sorted out because I haven't got a clue how VEMS manages them. If the car is idelling then I can set the injectors however I want them and the car works the same >:(
But the injector HAS TO inject into the cylinder in its intake stroke.

As I've seen other configs then there the injector outputs are set diagonally in the table
As in I've set them like this

This is just an exaple - in this version the injection order should be 3-1-2-4-5

So why do all others set them diagonally because then the order seems to be 5-4-3-2-1 :-\

To my understanging if the fireing order of the engine is 1-2-4-5-3 then the right injection order should be 4-5-3-1-2 That when cyl 1 is fireing then cyl 4 should be in it's intake stroke WHEN the injector should fire. Do I atleast have the basic understanding right? :D

So would someone PLEASE explain to me why everyone manages there injector outputs diagonally in the table?
« Last Edit: March 27, 2011, 10:09:43 pm by sink »

Offline mattias

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Re: Serious triggering errors
« Reply #29 on: March 27, 2011, 10:35:01 pm »
When you don't have a firmware with injector angle curve, you'll always be "wrong" so having a "diagonal" in the output table or not doesn't matter much (it does, but not in the good way).

The idea is to have the cyl 1 injector and ignition coil in the same position (row), the angle curve then delays the injection end angle according to the curve. Press F1 to see good defaults. The angle is referenced to each cylinders TDC on it's power stroke.