GM 4.2 liter V-6 Deactivation

[jwa4871]

Sounds easy, but I'll bet it's not.

I'll see what my mechanic will charge.

Thanks

[Jay2TheRescue]

Originally Posted by jwa4871

Sounds easy, but I'll bet it's not.

I'll see what my mechanic will charge.

Thanks

You would have to do the mod yourself. This would be an unapproved emissions related modification, and the shop doing the mod can be fined heavily. I would imagine most shops would not touch it.

-Jay

[jwa4871]

Oh Boy ! That leaves me with trying the 4 cyl alternative.

I note that the O2 sensor is a three wire setup, which I think means it is heated. Does that mean it is heated sufficiently to send the right signal to the computer?

[theholycow]

If there's no combustion on that side, the O2 sensor isn't going to have good data for the computer anyway. The only way to avoid open loop is to mount another sensor in the running side and switch to it when running deactivated.

[jwa4871]

At this point I'm pretty much decided on going with 4 cylinders, three on one bank, and one on the other bank. The cylinder on the other bank will be the one that will get the most heat to the O2 sensor.

I can't do the fancy work, and I don't want to get my mechanic in trouble. Have an appointment to do this Thursday morning. Stay tuned.

[GasSavers_RoadWarrior]

Well you could get your mechanic to install an additional O2 sensor hole, say it's for mixture monitoring, install an extra O2 sensor, then pull the plug off the dead bank and plug it into that one yourself.

[Jay2TheRescue]

Originally Posted by jwa4871

At this point I'm pretty much decided on going with 4 cylinders, three on one bank, and one on the other bank. The cylinder on the other bank will be the one that will get the most heat to the O2 sensor.

I can't do the fancy work, and I don't want to get my mechanic in trouble. Have an appointment to do this Thursday morning. Stay tuned.

My guess is that your crank will be under an unbalanced load if you only disable 2 cylinders. This will not be good in the long run. Disabling 3 will maintain an even load on the crank. If your crank is under an unbalanced load you will wear out your bearings and then not be able to hold adequate oil pressure anymore.

[ihatemybike]

I hope you're doing this on a cheap/spare vehicle. The GM 4.3L engine is a true runner, that lasts forever when you take care of them. Is your mileage really that bad running all cylinders?

[jwa4871]

No, I'm not doing this on a cheap/spare vehicle. It has only 44,500 miles on it, getting lifetime 17.3 mpg, and is in excellent shape. I'm doing this to provide an example of what can be done to conserve fuel. If it proves unsatisfactory, everything I am doing is reversible.

[jwa4871]

I should have mentioned, I'm heeding the advice of Jay2the rescue, am going with three cylinders in Stage One. Will check the mileage and acceleration to 60 mph. I expect because one O2 sensor will be cold, the computer will call for an enriched fuel mixture, bad for mileage.

Stage Two will have a muffler shop drill, tap, and plug a hole for a future O2 sensor somewhere ahead of the Cat. I will then personally swap the plug and the O2 sensor in the unused bank, as recommended by Road Warrior and Jay. If anyone thinks I would still be in trouble with the government, please so advise.