I decided to use Sea Foam to clean my 2000 DX's fuel injectors a couple days ago. I followed everyone's directions on here by putting it in a cup and feeding it through the vac line that connects to the little brass hub thing by the fuel rail. The only abnormal thing was that when I finally plunged the line into the last bit of Sea Foam to stall the engine...it sucked it all up, instead. So I tried again with a few ounces, and it chugged down all the Seafoam liquid again. At this point I decided that I would just cut the ignition and go on as planned. I waited 5 minutes and the car started up perfectly, with a bunch of white smoke as expected. I waited about 15 minutes until the white smoke was mostly gone, then shut her down for the night. The next morning she started up fine, but I got a CEL. I took it to Autozone, got it scanned, and the guy told me that there was a voltage problem with the o2 sensors, and that there was a voltage discrepancy. Thing is: I just replaced both of my o2 sensors with new SNGs 2 weeks ago, which had been working fine until the Seafoam cleaning! (I changed them as part of a tune-up, and because they were probably the originals, I had never gotten a CEL before) Is it likely that the ECL was only caused by a momentarychoking of one of the o2 sensors from all the smoke? Or did Seafoam actuallydammage my sensors somehow? I obviously had the CEL code wiped, but I have no idea if my new o2 sensors are working okay now. I'm tempted to pull out the sensors agian and possibly clean them with something? Is this a good idea? Any input would be appreciated. Thanks

 

Yeah, I think the seafoam has temporarily coated your O2 sensors and impeded their function. Driving the car for a while will probably burn off the seafoam residue. I don't think removing and cleaning the sensors would be necessary. Afterwards, clear the CEL code to verify that it doesn't return.

 

u say u had the CEL cleared, has it come back on since then? my guess would be the sensor was covered with residue and could read correctly. o2 sensors are very sensitive, i wouldnt take it out and clean unless its a last resort.

 

How many Ounces of sea-foam did you use you don't use very much through the vacuum line. But yeah it seem your O2 sensor was cover with residue. Maybe it will burn off

 

ya just drive the car a bit and then clear the code... and if it doesnt come back on it was just some gunk that came out of the motor that could have stuck on the sensor... hopefully it will just burn off.... but if the code comes back on again... THEN i would pull the sensor and clean it off.

 

Thanks for the input, guys. I already got the code cleared and it hasn't come back since. So hopefully the residue is already gone and my gas mileage won't suffer. I guess I'll just have to wait until my next fill-up to be able to tell...
Oh yeah, and I didn't use more than half a pint of Seafoam.
I was also hoping that someone could explain how CELs work. If it doesn't return, does that mean that I'm in the clear? If not, will the ECU just disregard the same malfunction because I cleared the code? I also already reset the ECU today (by holding battery cables together) since this all happened. Will that prevent it from ignoring future 02 sensor malfunctioning? And also, is there anything that is sensor safe that would work for cleaning an o2 sensor (in case I start getting crappy mileage)?

 

By using the OBDII scanner at Auto Zone you can delete the code. That scanner also does diagnostic when the Cel is on. Yes if Cel don't return you are fine but if it comes back go do the SCAN to see what code it reads and erase it again.

 

You only let the engine idle for 15 min after dropping in the seafoam? Whoever told you that is WRONG! Use 1/3 can and let engine idle for about 20, then drive it around the block a few times to ensure burn off of all excess cleaner. No wonder you had O2 problems, the sea foam was chokin em up. Do not remove sensors - the problem will go away, if it already hasnt. It all depends on how often you drive your car. All in all, it shouldnt last any longer than a day.

 

WHAT you say put it in and let the motor idle for 15mins..... NO NO NO you turn the motor off and let the stuff soak into the junk to free it up and THEN you start it up and let it run to smoke out..... i let it idle for about afew mins... and then i rev the motor up around 3K for awhile till the smoke starts to die down and then i take it for a drive till it stops smoking completly....
ive done it to several cars/trucks several times.... no problems and no CEL codes...

 

Yeah you gotta rev the **** out of it for a while ot make sure all of the junk is blasted out. i took mine for a 10 min drive with some idling and high speed runs and it was fine after that.