Question about shifting ignition order VEMS

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Question about shifting ignition order VEMS

Postby nmerrill » Sat Feb 23, 2019 9:24 pm

Well, now I'm stumped.

5 cylinder, VAG Hall 60-2 trigger, and distributor secondary- all set to factory alignment.
TDC after trigger set to 78, corresponding with Hall at tooth 14 (13 after FTT).

Triggerlog looks clean without errors.

Timing light on #1 plug wire flashes at #4 TDC (with ignition lock on 1Deg)

I shifted the reference tooth table three different times, maintaining the order, but shifting the locations
0, 24, 48, 72, 96
24, 48, 72, 96, 0
96, 0, 24, 48, 72 etc.

The timing light still flashes at #4 TDC - no change. I don't understand this!

Rotating in the ignition visual makes no change either, as it shouldn't, according to the help files.

Shifting FTT moves timing of light flash as expected. This isn't an option for this problem though.

I can't shift the ignition outputs because they are all the same pin = one coil on pin 35.

So, how do I get it to fire on #1 instead of 4?
nmerrill
 
Posts: 64
Joined: Jan 13, 2016

Re: Question about shifting ignition order VEMS

Postby varia » Sat Feb 23, 2019 10:48 pm

here is mine

1vems.jpg
1vems.jpg (313.59 KiB) Viewed 453 times


2vems.jpg
2vems.jpg (201.62 KiB) Viewed 453 times


tomorrow i will have time to explain it.
htwh
¯\_(ツ)_/¯

project 2226
varia
 
Posts: 315
Joined: Mar 18, 2013
Location: Los Angeles

Re: Question about shifting ignition order VEMS

Postby nmerrill » Sun Feb 24, 2019 10:07 am

OK! please do! trying to wrap my brain around what you've done...
nmerrill
 
Posts: 64
Joined: Jan 13, 2016

Re: Question about shifting ignition order VEMS

Postby nmerrill » Sun Feb 24, 2019 11:10 am

Well, experiments this morning had good results...
Shifting FTT is an option for this problem! I was thinking I needed to shift it 24 teeth to get far enough, but that was incorrect.

I shifted FTT to 12 (from 0) and timing light now fires correctly at #1 TDC, and all cylinders.

I think what this does is;
moving FTT to 12 adds 72 deg. of crank rotation, which is the distance beetween #4 TDC, and #1, so the ecu waits 72 degrees (12 teeth) before starting its count, which delays the Ignition trigger to the proper timing.
TDC after the TT still stays at 78 deg.

I don't understand why shifting the reference tooth table does not affect the ignition timing in this case. I clearly don't actually understand the reference tooth table!
nmerrill
 
Posts: 64
Joined: Jan 13, 2016


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