Do I have a decent trigger?

[lukej]

So today I got some feedback from the VR crank sensor on my Beetle, wired the sensor to pins 1+ 24 with the shielding connected to pin 2 (all soldered)
MS2 V3.0 Extra code 3.2.1

36-1
Tach input set to 'Basic Trigger' although I have tried 'Toothed Wheel' too.

r52 and r56 wound fully anti clockwise
Connected to the laptop it was showing ~18000rpm at idle
Tweaked r56 until defined teeth are shown in tooth log and composite log and I think I cleaned it up with r52. Nice and steady but only showing 460 rpm or so (1/2) what it should be.

I think I've attached a log... first timer

Tooth log.csv

(335.35 KiB) Downloaded 21 times

Does it look like I have a usable trigger at that? any reason why I am seeing 1/2 rpm?

Thanks for your time guys

[grom_e30]

set it to missing tooth wheel if its a 36-1. log looks ok btw

[lukej]

So
Basic Setup > Ignition options > Spark mode (dizzy, EDIS, wheel)?
'Missing Tooth' isn't an option in there...

Thanks for looking at the file

[grom_e30]

spark mode = toothed wheel


trigger wheel arrangement= single wheel missing tooth

trigger wheel teeth=36
missing teeth=1
wheel speed = crank or cam depending on setup

the rest of the settings will depend specifically on your spark hardware eg no of coils spark output used and the tooth #1 angle ect

[lukej]

Ah got ya.
So I set it up as you say... Idle is still 18k rpm or something daft...
Oddly, when I did a little RPM sweep up to maybe 4k and back down at one point it did start reading about what I would have expected... I saw 3xxx rpm flash up which makes me think it's nearly right
I have attached a few more logs, if you could have a quick look that'd be awesome

Composite.csv

(537.79 KiB) Downloaded 20 times

Composite rev sweep.csv

(1016.89 KiB) Downloaded 21 times

Tooth log.csv

(46.57 KiB) Downloaded 21 times

[lukej]

Tooth log rev sweep.csv

(41.1 KiB) Downloaded 19 times

[lukej]

I updated the firmware... Just to rule out anything there... now running 3.4.2 and guess what...
Trigger is working perfect

I only ran it up to 4000 RPM or so as it scares me a bit going higher than that
But looking good... Now onto the next mystery tour.

Thanks again for your input Grom.

[grom_e30]

you appear to be triggering off the wrong edge rising/falling, in the tooth logs you can see this by the long tooth having a longish tooth next to it. switch the edge and it should get rid of the longish bar

[lukej]

Ah ok good spot... It is likely seeing as I did flip that option at least once

Wired the coil in.
Fords edis coil (minus the EDIS)
Left wire to Spark A (IGN which is pin 37)
Middle wire to switched live from the standard coil
Right wire to Spark B (IAC2B which is pin 31)

With the engine running still on the distributor but the new coil wired in I got sparks on all 4 plugs... Ms doing what it should so far. So I slipped the ht leads off the ford coil onto the engine and tried to start it up.
When cranking though I have no tach input. I dropped cranking rpm down to 500rpm (from 650) but still nothing.

I have called it at that, getting dark here and the battery is probably a little tired.

Any ideas why I am missing the trigger when cranking? Is that a matter of fiddling with the trigger/hysteresis pots again?

Cheers.

[grom_e30]

may well be a case of adjusting the pots, usually cranking it is harder to see the vr signal especially at a lower engine speed.

have you got the correct tooth #1 angle set? if this is not correct you will get the spark happening at the wrong time

[lukej]

Well that's something I've just been scratching my head over...
I put a black mark on the pulley around 5 o'clock where the missing tooth is. The Sensor is at 90º 3 o'clock



If the sensor was at tdc the offset would be ~130º. With the sensor being 90º ATDC I think the offset should be 40º

[grom_e30]

if you set the engine at tdc and count the gaps....

http://www.msextra.com/doc/pdf/html/MS2 ... 4-125.html
http://www.msextra.com/doc/pdf/html/MS2 ... 4-126.html

explains it

[lukej]

OK so I have tried 230º and 320º... No joy. It's back fired once or twice...

I think my problem is still trigger offset... With the pulley at TDC it has to rotate 230° before it sees tooth #1
Or 90º as the sensor isn't at TDC
Have I got that wrong?

[grom_e30]

if that pick is with the engine at tdc with clock wise crank rotation and each red line represents a tooth on the trigger wheel sensor is over the 5th tooth so that would make the tooth #1 in the region of 40 or so degrees

[panel]

To me that pic looks like it should be rotated 90° clock wise so as not to confuse anyone......I don't think that's TDC.

In the one pic you said the sensor is at 90º 3 o'clock.......but in the other pic you have it as 12 o'clock.

[lukej]

Don't worry about where the pulley is in relation to that engine block... Its the only head on photo I have...
With the engine and pulley at tdc the sensor is at 3 o'clock

40° OK so I went the wrong way... I'll try it

[lukej]

No joy at 40º...

[grom_e30]

if you can still run the engine with the dizy you could then set the ecu to fixed timing 0btdc and run the engine and use a timing light on the ecu controlled no1 plug lead to check the tooth #1 tdc mark should line up with strobe light if its correct.


is it still having trouble syncing up when cranking??


edit: post a copy of the current tune so we can see what your working with here

[lukej]

It lives

Someone on another forum has the same trigger wheel as me... They have theirs set at 52º, I went out and tried that with no joy... I got the engine running again on the distributor and checked timing against my Ford coil... Found No1, no 2 etc and paired them up

1...4
3...2
plug

And hey presto...

Grom, that bar I was getting before the missing tooth... Turns out I had the sensor wired backwards. I changed rising/falling edge and lost the trigger, changed polarity of the sensor and bingo- cleaner trigger

[grom_e30]

nice one. now it runs you should use the strobe light out and dial in the tooth #1 to make sure the spark timing is correct

changing from rising / falling should have the same effect as switching the sensor wires btw