o2 codes

[johnv]

Hi,
A mates VT Commodore has been throwing o2 codes since fitting headers and removing cats(o2 low temp both banks etc).
Can we alter any of the o2 cals to prevent this happening ?

Cheers
John

[GMPX]

John,

VT's were notorious for throwing 'false' O2 codes.
We've not added in the O2 diagnostic parameters, however, If you wish I can send you a tun file that was the 'official' fix from Holden to solve this issue.

Cheers,
Ross

[johnv]

That would be great thanks Ross.
Will I need the commercial version to load this tune ?

[GMPX]

That would be great thanks Ross.
Will I need the commercial version to load this tune ?

Sorry John,

I was confused, the early VT updates were for false knock sensor codes, not O2 codes. I remember this happening to VT's when extractors were fitted, it never happened on my own VT so I never investigated the problem too far.
Maybe a nice kind tuner on the board might give you the solution!!.

Cheers,
Ross

[johnv]

Ross,
yea he was told by dealer that he may need to move the o2s closer to headers.
woundering if I were to upgrade to commersial and load a later model OS weather that might cure it as it doesn't seem to be as much of a problem on the later model Holdens.

[GMPX]

Ross,
yea he was told by dealer that he may need to move the o2s closer to headers.
woundering if I were to upgrade to commersial and load a later model OS weather that might cure it as it doesn't seem to be as much of a problem on the later model Holdens.

That I don't know.

Cheers,
Ross

[jsttry]

Silly question but have you tried replacing the O2's or swapping from a known working car just in case they were damaged during the install of the new headers?

[johnv]

No, but both right and left o2s are throwing the same codes so unlikely they are both caput ! but not impossible !

[Blacky]

Ross,
yea he was told by dealer that he may need to move the o2s closer to headers.
woundering if I were to upgrade to commersial and load a later model OS weather that might cure it as it doesn't seem to be as much of a problem on the later model Holdens.

My VT spent nearly as much time at the dealer as it did at home, while it was under warranty. One thing the dealer told me was that the O2's were directly under the A/C outlet and that the water dripping onto the O2 sensor would cause it to not reach operating temp or damage it.
I have no idea if that is true or not. I presume it can't apply to both O2's since both of them can't be under the A/C drain, but it could explain why the dealer wanted to move the O2's.
Paul

[Steve Bryant]

johnv,

You said that you removed the cats. Did you install your secondary O2 sensors down stream of the primary 02's? If the secondary 02's differ from the primary O2 in activity level, then that tells the PCM that the cats are working. However, if the primary and secondary pretty much match in activity level, I would imagine that the code that would be "thrown" would be cat convert fail. Without the cats, the similarity in voltage outputs (primary and secondary O2) could trip some kind of O2 DTC.

What is the approximate distance from the exhaust ports for cylinders 7 and 8 to the primary O2's in inches or Cm?

All my best,

Steve

[johnv]

Not sure of the distance o2s are from ports, will get my mate to have a measure and compare to mine on a VXII Commodore (also headers and cats removed and no problems)

No secondary o2s on the Holden LS1s :)

Cheers
John

[Blacky]

No secondary o2s on the Holden LS1s :)

Hehe!
The only cats my VT saw were the ones scampering off the road...

Well that is until the dealer made me put them back on before they would perform any warranty repairs. It was the dealer that took the cats of pre-delivery (and charged me $1400 for the "aftermarket" exhaust system) - go figure!!!

Paul