VEMS on 7A flywheel - Scope

[Nuno_Cristiano]

Hi,

I have a next problem. VEMS detect primary trigger in log file but secundary trigger no.

Actually i use camHall invert is OK and i measure with scope JP20 signal directly ( Secundary trigger VR ) and CamHall input in EC36-13.

By datasheet of LM1815 in MODE 5 put at 5V the output is active if measure peak-to-peak more that 200mV. Actually i think my problem in reference pin in 7A flywheel. I have peak-to-peak " only " 200mV.

Anyone confirme if the problem is it?

Many thanks.

[varia]

I didnt scope mine, but when I sent my trigger log to Marc, he was almost crying, it was so weak.
I tried to move the bracket that holds the 2 sensors closer to the pin, nothing.
Car wasnt running, i didnt have welder or lift, so I couldnt weld a bigger pin. And even if i could, there was chance that it wont fix my problem.

So i ended up installing a rear 60-2 crank shaft seal:

[blackS2]

what firmware version?

[quattro-nick]

the timing pin on flywheel is to small,i made mine bigger with metal and there are other threads here on the forum about this problem

[prj]

The pin is not too small.
VEMS trigger pickup is ****. The 20+ year old stock ecu works just fine with this "small" pin.

You can bodge it by welding some material onto the wheel, so the signal amplitude is bigger. The fix would be for VEMS to get proper trigger pickup.

[GazzaG60]

i had an exact replica of the aby unit mounted on the flywheel lightenened and balanced.

works fine.

[Tille]

My VEMS worked fine with original 7A Flywheel and Pin. FW 1.2.31 AudiTrigger DivideByN

[GazzaG60]

it seems hit and miss.

usually best to do some mods to pickup before its rebuilt to be sure.

[Nuno_Cristiano]

Morning,

I measure in prove in scope reference pin was wrong. I measured 200mV p-p but is 2V p-p. My sorry. So the problem is not reference trigger.

My battery was a bit low and i put my stabilizer of tension to 13.5V and after i crank the car start normally. Is battery down of 9.5V VEMS cant´read the trigger that is strange... Increasing tension engine speed is more stronge and engine goes up very nice.

Many thanks to all.

Firware actually is 1.1.80. Any suggest to update?

[GazzaG60]

im looking to do this soon. now mines running again.

1.1.8 should be pretty good id expect. im still on 1.1.23rc. very old. just about readable with vemstune.

I doubt mine would crank at 9.8v let alone start and run well.

[A80Avant]

As above. I had my lywheel welded with a pin similar size to the OEM rs2. Also make sure it's not SS as it won't work.

Sent from my SM-G850F using Tapatalk

[diesel des]

7a flywheel was always a problem in till I machined the back flat like a 3b unit and fitted a larger pin. No problems now.

Sent from my LG-H955 using Tapatalk

[blackS2]

My VEMS worked fine with original 7A Flywheel and Pin. FW 1.2.31 AudiTrigger DivideByN

had trigger issues - tried everything in VEMSTune plus grinding shifting the sensor bracket... + new sensors-- no difference...

after FW 1.2.3x all issues where gone

[GazzaG60]

as des said make the 7a flat. mine was done like this as it also aids mounting the aby timing point.

[kamuto]

I don't know, I'm sometimes making p&p ecus for audis, haven't had any problem like 3 year, totally no problem with stock pickup