S80 o VR6 turbo

[ibizacupra]

Hiya
I have used DTA since 1997 on 4cyl, but have a vr6 turbo here with S80 supplied..
Wired in and running now, BUT....

I am getting crank sensor signal errors, causing severe misfires once rising to 4krpm... pops and bangs as it looses its synch.

Wiring had reused its oe sensor loom reterminated at old ecu position..
Tried another crank sensor from an aeb 1.8t as plugs were the same. Same issue.
Sensor fitted is from gsf, non genuine as its oe sensor had open coil.
1.8t one was working one out of an a4 I "borrowed" it from today.
Rewired the crank sensor with new supplied screened twisted pair which you get in DTAs pre-pinned wiring kit. Segregated it from anything coil related and routed it to the crank sensor away from anything coil HT... I have had a similar issue on my 1.8t racecar a few years ago where my wiring for crank sensor passed by the coilpack and that upset the ecu. Moved it away and problem free. No so on this one.

kind of running out of ideas now.

any suggestions guys?
thanks

[Roverdose]

not really much use but my v6 has had some random crank sensor issues.

thankfully seem to have disappeared (famous last words), but I had a few issues with it not reading the crank signal at all. changed to another, no joy, changed to a cam sensor that didn't really fit and it started working, just. swapped back to the original crank sensor and its been working fine for a year or so!

odd, and no use. great post

Drew

[stevieturbo]

Can you do a proper scope trace when the problem is occurring ? Not a DTA scope, proper oscilloscope.

[ibizacupra]

Can you do a proper scope trace when the problem is occurring ? Not a DTA scope, proper oscilloscope.

yea, should be possible.

no cam position sensor wired in currently.. running non-sequential so didn't think it was required.

got any settings for VR6 I could look and see for engine config?
thankyou

[stevieturbo]

Although ultimately if you're getting tooth errors and re-syncs, there is a problem.

But a proper scope trace would give a better clue as to what is happening the signal as DTA doesnt give the user any control over trigger voltage levels etc

[ibizacupra]

Uploaded a vid of the scope trace. Will try and link it to here. Voltage peak to peak 40v when revving. Too high? Wave form looked ok to me but crank signal gets lost when you get to 4krpm level

[youtube][/youtube]

[ibizacupra]

[ibizacupra]

video is showing scope with probe on x10, 5v/division as it goes off scale otherwise.. Lots of voltage.

I tried a oe working 1.8t crank sensor and same scenario.

[lumley32]

try swapping the sensor polarity!

[ibizacupra]

try swapping the sensor polarity!

reversed it would not start with next to no signal