OX66 questions

[Parker2510_OX66]

These have certainly been asked before, but....

I have an 02 OX66 SX225TXRA and I need to know the following. I have looked thru the shop manual and googled the internet. The shop manual is, well...... It has a lot of good technical information but it does not have everything, and in some cases it could be better.


Is the number one cylinder sniffed by the O2 sensor or is the number one cylinder on the port side of the power head?

Which cylinder is inactive(for lack of better wording) when at idle or under 800 rpms(or there about). I believe this to be cylinder 5 from research but would like to confirm this.


Appreciate the help!

[boscoe99]

The number one cylinder is the top most starboard side cylinder. It is the number one cylinder that is drilled to accommodate the oxygen sensor.

The diagram below depicts which cylinders aren't firing, and when.

[Parker2510_OX66]

Thank you Sir. Most helpful.

[mjm-1957]

Is there anyway to disable this annoying system? I was told the Vmax didnt use CCS, other than installing an ecm from a Vmax is there any other way? Can't understand the reasoning behind disabling two cylinders and creating a shaking engine.Thanks,Mike

[boscoe99]

Yes. Would involve a small bit of engineering and a few parts but it can be done.

[mjm-1957]

Would really appreciate any help in knowing what to do to disable it?Thanks

[scofflaw]

That small bit of engineering ain't gonna happen

[rodbolt17]

buy the VX ECM
but why?
CCS worked and worked very well.
most bass boat motors(VX) do not spend much time idling or *****ing.

[mjm-1957]

Mine is not a bass boat,Grady White SeaFarer and it is used for quite a bit of slow speed operation and *****ing,the engine runs great in every other way but the shaking at slow speeds and idle is really annoying.I have been watching ebay for a used Ecm but they are far and few between. I'm a GM dealer line mechanic and worked for Cadillac for 23 years and we used to disable the 8-6-4's all the time.I just wonder if there was a simple way to trick the Ecm into not going into cylinder disable?I work for a Buick Gmc dealer now and there are ways around the displacement on demand systems currently in use also.(AFM)

[rodbolt17]

instead of jury rigging why not simply fix it??????
I was an auto tech when Cadillac did the 4 6 8 thing.
what a joke.
the concept was good the technology of the day did not support it.
the S and SX 3.1L EFI motors did NOT suffer that issue.
they worked and worked well.
the VX motors typically are not used for *****ing.
the whole concept of CCS was for better extended low speed use.

if you fix it you will find it works.

[Parker2510_OX66]

I just put 150 hours on my SX225 this summer cobia fishing. I typically run around 1200-1500 rpm's while siting for fish. I find no issues with the cylinder on demand or even at idle. My motor typically runs very smooth. My buddy has a SX250 which we ***** for rockfish in the fall months but at idle speeds and even using a happy *****. no issues with his either. If its rough, as you describe, you may want to look into why its rough. Ours typically run like sewing machines. If they aren't then there is an issue some place. I have another friend who has a SX225 who cobia fishes his and has 2700 hours on his. Same thing.


Boscoe, again, thanks for the Diagram and answers. helped me pinpoint my issues.