The Project Pad

So, since I updated FW, my WBO2 has not been heating. I am using the settings recommended here but the O2 "works" once it is heated by the exhaust. I just got a new sensor and still cannot get it to cal/heat.

Is it ok to test the heater circuit without attaching the resisters as described here?

Ed, what ended up being the problem here? I have the same issue

TBD, I haven't really done anything on the Coupé since I bought the 90.
I need to sort this out along with some other niggles, the WBO2 wiring is all new (vems harness) so unlikely it is the problem.

I'll let you know if/when I figure mine out. Where did you put the VEMS box? I haven't figured out where mine is going to live. I had it right above the pedal cluster for all testing and have it disconnects right now while I reinstall the interior. If the harness were about 6" longer I would put it in the cubby right there but it likely won't make it the way it is now.

For what it's worth, I was able to test my o2 sensor harness and VEMS using the above link with some radio shack resistors. Had to put some in series to get the right resistance.

Mine tests out correctly at the end of the harness so I have some other problem. I think I have something wired wrong. Will be pulling my harness apart to test some things this weekend

I may roll back to the old FW version just to see what's up.

Mine ended up being fixed by changing the source of 12v. Was using the 87a pin on the underside of the fuse box (switched from fpr).

Changed the source to the ignition switch 15 pin and heated right up!

Sweet. That should help a lot, lol

Have since changed to pin 86S from the Ignition switch - on pin 15 some voltage was leaking through to the door chime.

now works like a charm.

I was working on a new & relocated IAT sensor so I decided I'd test this, I have a short somewhere which is feeding the WB02 +12v ALL THE TIME! I guess I'll add reevaluate battery relocation/+12v feeds to the VEMS harness to the list I replaced the battery that came with the car about 6mos after going VEMS and figured it was simply old (it was fairly old); hopefully the new battery is not dead (I've been jumping it, figured it was simply low from sitting forever, cranking to troubleshoot, and not running long).

Don't use switched 12V for heating up the Sensor... the Sensor needs a regulated supply by ECU or it will overheat...

...use another firmware because there are some issues with some 3.6 boards in combination with FW 1.2.30/1.2.32...

black wrote:Don't use switched 12V for heating up the Sensor... the Sensor needs a regulated supply by ECU or it will overheat...

...use another firmware because there are some issues with some 3.6 boards in combination with FW 1.2.30/1.2.32...

I just saw a, your?, post on the VEMS facebook group about version this morning.

WRT switched power...

VEMS gave me this:


I'll likely change it to this (as they since have):

Mcstiff wrote:

black wrote:Don't use switched 12V for heating up the Sensor... the Sensor needs a regulated supply by ECU or it will overheat...

...use another firmware because there are some issues with some 3.6 boards in combination with FW 1.2.30/1.2.32...

I just saw a, your?, post on the VEMS facebook group about version this morning.

WRT switched power...

VEMS gave me this:

No not mine...

maybe my post above could be misunderstood...

12V power is from battery, thats right but ground has to be controlled by ecu. What I would say was, do not power up Sensor Heater permanently via direct voltage and ground by battery....

black wrote:

Mcstiff wrote:

black wrote:Don't use switched 12V for heating up the Sensor... the Sensor needs a regulated supply by ECU or it will overheat...

...use another firmware because there are some issues with some 3.6 boards in combination with FW 1.2.30/1.2.32...

I just saw a, your?, post on the VEMS facebook group about version this morning.

WRT switched power...

VEMS gave me this:

No not mine...

maybe my post above could be misunderstood...

12V power is from battery, thats right but ground has to be controlled by ecu. What I would say was, do not power up Sensor Heater permanently via direct voltage and ground by battery....

Ok, yes, I misunderstood. I believe VEMS is controlling the ground.

black wrote:Don't use switched 12V for heating up the Sensor... the Sensor needs a regulated supply by ECU or it will overheat...

...use another firmware because there are some issues with some 3.6 boards in combination with FW 1.2.30/1.2.32...

Also, I'm on 1.2.1x not sure we can blame fw

Well, it's not the sensor. I guess I need to triple check the harness.

I need to double check but my issues may be rooted in having LSU 4.9 sensors... http://vems.hu/vt/help/v3/v3_wideband_settings.html

Once I work that out, I'll get back to the testing.

Nevermind, I looked at switching but still using the 17014 LSU 4.2 sensor
So far I've measured the following at the sensor end of the harness with the engine running:

Verify Pump: ~4v
Verify Heater: Heater + has 12v

TODO:
Get resistors and figure out this test harness
Test heater -
Measure the voltage between pump(-) and pump(+)
Nernst-DC target

Ok, I'm feeling good that the vems harness is good and things are in the correct place.

Get resistors and figure out this test harness: ?
Done, interestingly the resistors made the WBO2 Cal think the heater worked.

Check that voltage between wbo2_pin1 and wbo2_pin5 reads appr 0.45V (0.44V or 0.46V is just as good). If it's slightly out, you can adjust the value by typing: Manmttg89c85mcs and adjusting the value 85:
I'm seeing the V here bounce around with a peak around .4V but most of the time it is much lower.

Test heater -
Measure the voltage between pump(-) and pump(+):
This is way high at 123mV but I'm not 100% the WB is off. Should be between -4 & +4mV with the WB off.

Nernst - DC target
"nerst to pump" - never gets above about 30mV but should be +450mV

Changed my Ri target from 180 to 165 which was used on an old tune when it was working. Does not seem to have helped.

Ok, this is fairly clear (aside from being written before VEMSTune): http://megasquirtavr.sourceforge.net/ma ... ml#Operate

Do not turn on the WBO2 heater or take these measurements with the engine running (WBO2 heater will turn on when trigger events are occurring) unless told to do so explicitly.

So if this is correct, so long as I do not have the WBO2 calc tool on my measured value between pump + & - is way out of range.