I use the Seafoam Bob religiously and love it for use in oil for cleaning stuck rings and cleaning buildup around seals and such , as a gas treatment and it is a fantastic intake cleaner and will not harm the 02 , but like in the last post , if you have heavy deposits in the intake it will be made known by larges volumes of smoke , I always use it in the intake until the smoke is gone or very little , this usually takes 2-3 cans to achieve this if not regularly done .
The only reason your 02 would fail due to this would be that the deposits burnt have clogged up the vents on the sensor shroud , never had this happen yet but a cleaning of the shroud with a brass bristle wire brush and then a washing with sensor safe cleaner of the sensor itself within the shroud should correct that

Guy

 

I pulled the computer out of my 94 to check it out, years of plowing snow has left fender rotted away behind tire, has left it with a sizeable gap between inner and outer fender. Do not believe for a second it provides protection from water, a lot of it, from drenching the computer driving in rain/slush/snow etc. Just gonna move it to higher dryer location, likely last year for that truck anyway. Bungee Cord to top of under hood fuse box or similar.

While I had it in my hand I opened it, looked pretty good but yea one questionable cap. Wouldn't say it leaked no not yet but likely not far from it either by looks of things. I found was carbon trace from that caps positive leg leading across the board to the nearest diode leg about 3/8" long, carbon trace was about thin as a hair tad thicker maybe. Thought it was a "hair" unit I brushed finger crossed it it crumbled/disintegrated.

Had no signs of troubles, it run fine and fuel mileage "normal" for it. Thinking the damage I did find was from a little water intrusion. While I did find it was "dry" inside we are just coming out of drought conditions here, had plenty of long hot days to dry out. That and or perhaps my swapping batterys in it while running!

I took it to a local TV repair shop just up the road, he's replacing all three caps for 10 bucks plus price of caps. Figured what ta heck he's got a lot more experience with the board level type of repairs then I do = 10 bucks well spent. Told him order enough to do at least two of em, when hes done with that one I'll bring him the one out of my 95 nip this whole thing in the bud.

 

In my opinion , if it died as a result of that , it was already on its death bed , to date I have never killed a 02 sensor with Seafoam and I use it on everyone's vehicle I touch in one way or another and that is 1000's over the years , I use it in small engines and marine applications as well , I love that stuff

 

See , this si what I was speaking of in my long winded explanation , the cap can be leaking without the puddle or obvious signs , like any oil , it can be leaking in a vapor state when getting hot either as a result of premature rupture and major leakage or as a result of just heat , that is why I posted the specs that showed life at 1000 hrs @ 205*F , anyone can do the math on that and realize its life is very limited if you consider how many times and or situations it would see 200* , not very hard , also considering the fact that there are two separate heat sinks in the box as well , I digress again , back to the carbon trace , if this cap had been leaking electrolytic oil vapor then it would lightly cover the PCB , and again present capacitive type conduction , no different than you would see in a Dist Cap and or tracing on a Coil body , it does not have to be high voltage for this to happen
It happens all the time !
Also like yours , mine was spotless , the plug pins were clean and well lubricated with some type of di-electric lubricant and the inside of the module was spotless as well , I was impressed to say the least , because like you said , there is little protection , the inside on this engine compartment is covered with muddy water , every last inch lol .
Also once you get that capacitive conduction , then over time the trace , then you start getting real time resistive type conduction , that is when the real damage starts to happen depending on what is involved


Guy

 

I'd say that's very good preventative maintenance.

Is it safe to to say that this thread (discussion) swayed you to remove your computer and give it a visual check ??

Good on you !!!!

Bob

 

I will kindly disagree with you. Some GREAT info on O2 sensor theory and operation from Ryan at Oldfuelinjection.com: Fuel Injection Technical Library » Oxygen Sensor (HEGO)

If you have more documentation I would gladly read through it. I am always looking for more info to prove or disprove accepted theories of how things work!

 

I stand sort of corrected , my explanation was lacking , the O2 sensor does work via resistance and can be triggered by temperature regarding the operation depending on the computer control , it does measure the presence of the oxygen by way of bi-metal reaction to the presence of oxygen which changes resistance and then changes voltage supplied back to the module in the form of varying voltage.
This is why I said it was not a switch because it is not off and on per say but rather nothing more than a variable resistor of sorts , it does detect oxygen but does so that it changes resistance according to the oxygen levels and communicates to the module that info by voltage changes as a result of the resistance change in the sensor .

I stand corrected

Guy

 

This may explain a little better what I was trying to explain :

"The sensor does not actually measure oxygen concentration, but rather the difference between the amount of oxygen in the exhaust gas and the amount of oxygen in air. Rich mixture causes an oxygen demand. This demand causes a voltage to build up, due to transportation of oxygen ions through the sensor layer. Lean mixture causes low voltage, since there is an oxygen excess."

Guy

 

Still not right. It physically generates a voltage, it's a fuel cell. There is no resistance changing going on in regards to actual A/F measurement. The computer does not send a voltage to the sensor and measure the return voltage - like most other sensors.

The +12v you see the sensor getting is purely for the heater, nothing else.

"The zirconium dioxide, or zirconia, lambda sensor is based on a solid-state electrochemical fuel cell called the Nernst cell. Its two electrodes provide an output voltage corresponding to the quantity of oxygen in the exhaust relative to that in the atmosphere."

You could take an O2 sensor, remove it from the car, put a torch on it and measure a voltage between ground and signal.

 

I believe they actually do both regarding application , one that generates Voltage like you said and I was wrong about the bi-metal reference and then one that actually changes according to the oxygen present but is resistive , one would supply voltage while the other will be in series and according to the resistive changes from the sensor would change supplied voltage , I will try and find the documentation on it to show you , may take a while , I got 40 irons in the fire right now

Guy

 

I have a similar problem with my 91 F350 and have been following this thread. Did you get the caps in? BTW, stoichiometry is the correct term for the O2 sensor.

 

I am sorry so long , it is a sad story :
I found the caps on the Radio Shack Online Store , ordered them , was supposed to get them this past Monday .
Monday Morning I get up all excited , already had my soldering iron , rosin core lead free solder , electronic surgery tools lol , and all fired up.
Only to find that they lost the package in or at the Haggerstown MD Distribution Center .
So I called FedEx , and they are like really ? , Let em check , Oh we are sorry .
And it gets even better , they will do nothing about it except track it for 10 days and then let me know if they find it , and I am supposed to call shipper and fix the problem even though they lost my items .
So I call Radio Shack and ask that they re-ship , they tell me "Oh we are sorry , we do not re-ship items , if the item is lost , you have to wait 14 days , and then if it is still lost , we will refund the order and then you can re-order ( and wait another 5-7 days )" .
So I told them I wanted a refund and they could file a claim with fedex , and if they did find it , just ship it back to them , they said " Oh we are sorry , but we cannot process your refund until 14 days , and you would have to file a ticket with us and then we will refund your purchase within 7-10 days later .
So I was a bit miffed at this point and said ok , if they find it I will just refuse it and when you get it back you can file a claim with FedEx and then at your Leisure refund my money back to the Credit Account Purchased with , they said , No Sir , we can not do that , if you refuse it we will only refund the amount for the Caps , you will not get the shipping fee refunded , now I am getting rather aggravated ( almost $10 Shipping for $1.80 worth of parts , three very tiny caps ).
So I told them I will refuse the shipment if they find it , and either way , they can keep the money and I will never do business with them or their stores ever again , this may seem rash but both Radio Shack and fedex have pitiful customer support .
So now I have waited over a week to find out I have to wait another week before they will consider re-shipping and then wait another 5-7 days for the parts , Blood was boiling by this time .
So I abandoned all that , and will refuse package if it gets here , and will never do business with radio shack ever again at this point and considering black listing fedex as well though this is the first time they have ever lost something , the customer support was pitiful , I told them all the info each time I called and each time they told me it was my fault they could not do anything because I had given them no info , and each time I did speak with a person I told them what the order was , the quantity , even the blasted values , voltage and size dimensions , this is none the less unacceptable and I may never use fedex again as well .

The good news is this , after all this mess , I found a company that has even better quality caps ( I got the Panasonic) , they stock more than several diff manufacturers of electrolytic caps , I will share the link here :
Electronic Parts, Components and Suppliers | DigiKey

This is DigiKey Electronics Distributor , they deliver same day , same high temp caps , and all 3 caps of better quality cost less than a dollar from these guys !
They buy in quantity so cheaper and they do not drop ship .
All that said I should have the caps on Monday or Tuesday , when the tracking updates tomorrow or Monday , I will know better , it went USPS this time Priority Mail , so seeing I ordered on Friday , I may receive Monday as postal mail does travel on Sat as opposed to ups and fedex which do not .
I still have all my tools here waiting for them to come in , I do not get mail until 5ish , but I will post here as soon as I get them , in that case I will replace and hopefully have enough light left to install and test
Sorry , I should have posted a update but have not been happy about all this , sad sad customer support makes me very very aggravated .
Positive side is this DigiKey Company is fantastic !

Guy

 

Guy: I'm sure you have heard of these folks... Mouser Electronics - Electronic Components Distributor

They have always been top notch for me....

A man can never have too many sources!!!!!

You had better update your arrival dte to Tuesday,, Monday is Labor Day.....

 

Mouser, Digikey, all good outfits. Can't get much better then Panasonic capacitors.

 

Criminey sakes, I knew something was awry when the days passed and we hadn't heard from you.

Hope you get to end this saga soon and enjoy your truck.

Still standing by,

Bob