I know the O2 sensor measures how much unburned oxygen is left in the exhaust. It also tells the computer when to lean or richen the fuel mixture.

You are right about it Seafoam being combustable butthe product will not burn completely. I bet it burnwill completely with an engine compression higher than what is in our 4.3's. Compression higher that 8:1.

Someone should tap a sensor with an O scope and take down the values. Then pour in Seafoam in the TB and see what becomes of the values.

I read that a properly functioning O2 sensor will exibit a fluctuating voltage signal atlernating btweeen .2 and .8 volts. (when in a closed loop.)

This is the extent of my knowledge of thisdiscussion some I am now going to shut the .... up.

I got an oil change to do and have to empty the oil catch can.

 

True, that is the function of an O2 sensor. So while you are pouring the seafoam into the intake, this should cause a rich signal from the O2 sensors, which would intern prompt the PCM to decrease the IPW (injector pulse width), leaning out the gasoline mixture. There is no doubt in my mind that the trace from the O2 sensors will be different when you are actively pouring in the seafoam. I didn't look at the sensor values with my scan tool while pouring the seafoam in, but I have scans from before and after the seafoam and they are no differences as far as O2 sensor activity and range.

O2 sensors under normal operation are oscillating between ~200 and ~800 mV. This oscillation is happening quite fast. Typically, as the O2 sensors age, their activity (the frequency of oscillation) decreases. This is what causes poor fuel mileage because the PCM isn't receiving the information from the O2 sensors fast enough to make the required corrections. As such, it is constantly over correcting.

 

i have 209k on my engine. should i run it thru mine? will it help or mess it up?

 

I would suggest it, but its really up to you. Also from what you said kyle, changing the o2 sensor wouldnt be a bad thing to do if you are looking for better MPG?

 

yea i noticed my engine was runnin like **** today..could this be a cause from the seafoam?? cause it felt like i had no power what so ever and it jus sounded funny...

 

Have you done the upper intake cleaning? Have you changed the oil yet in the engine since you put the seafoam in?

 

ya know i found that when u start cleaning and changing things, no matter what u use, that new sounds, feelings, and problems arise. for so many years a truck will run with sludge and deposits that even though they are wearing down an engine, they probably also keep things from having too much play, or having too much lash. for instance lets say a valve guide has enough depositsyet still allow for a smooth operation. now u take all those deposits out and it could now be a loose or leaky valve. or all the sludge and oil deposits in ur pan could even possibly come loose. and we know what that can do!
my point is that sometimes an additive or engine flush/cleaner may not be the answer to ones problems. that we should take care of the deeper issues and use the additives as a supplemental benefit to any repairs or upgrades we may do. then sticking to the proper oil change schedule and occasionally doing a complete tune up should be enough to keep ur truck running smooth.
one last note. when u use any crankcase engine flush, u risk the chance of loosening pan sludge. so my advice would be to drop the pan before theflushas well. clean it very well and reinstall with a new gasket. then flush or seafoam the crankcase.
just my humble opinions........

 

i didnt do a upper intake cleanin yet..i am going to do that before i change the oil in a bout 2 days also..Do you think the seafoam could cause the CAT to go bad cause all the symptoms that are happenin to my truck is a sign of a bad CAT ( IE..Not that much power, Fuel MPG is bad, and also the other day i noticed the CAT was way hotter than the piping or muffler)....so could it also be the CAT??

 

If its only been in the oil, then it has nothing to do with the rest of the system.

 

i see that its an 87 and if u dont know if u have ever had a new cat installed, then i would go and change it anyway. the things will deteriate and clog themselves up, plus when u do do the upper intake cleaning then ur cat might just even get worse from all the carbon passing by or at least trying too.