Good Morning, Readers! [Ok, this didn't post until exactly 12:00 ET...]
I worked until closing time at my store last night, which gave me a great idea for today's blog post. I had a gentleman call during the last business hour, wanting a quote on an "air-filter-oxygen-sensor" for his F150. I pulled up our catalog system and plugged in his truck's information, then verified what part I heard him request. The problem, dear Readers, was that the part name he mentioned didn't make sense. I asked him if he had needed *two* parts - an air filter AND an oxygen sensor - or just one. He told me 'one'.
I brainstormed for a moment, then noticed he had someone in the background telling him what to say. It sounded like that person was trying to read something that was jotted down for them, but perhaps in a short-hand way. A-ha! I knew that some oxygen sensors were listed as "A/F (Oxygen) Sensors", for a technical reason that is not always explained well to the public. So, I suspected that the "A/F" was misinterpreted as 'air filter' - which is a common old-school abbreviation that even I still use - when really it was just an oxygen sensor. I asked the gentleman if the part was written down as "A/F", and he confirmed. Whew!
At that point, I went ahead and looked up the oxygen sensor, but also asked if he was basing this repair on a code. He said yes, that his truck was giving him a code of "P0171". I went to my reference website, where I saw this code was "System Too Lean (Bank 1)". Hmm. That said nothing about the Oxygen Sensor, just that the Bank 1 (#1 cylinder side) of his engine was not getting enough fuel. I asked him if he had noticed any performance issues with his truck. At first he said no, but then he qualified it with, "well, sometimes... when I'm on the interstate... but it doesn't last very long." While I was at it, I asked him if there were any other codes, and he said one other came up, "P0174". By the way, that code is "System Too Lean (Bank 2)". (Bank 2 = the non-#1 cylinder side of the engine.) Double-hmm.
I went ahead and quoted him an upstream oxygen sensor anyway - just in case - but I explained to him a few of things:
1. A/F oxygen sensor = special type of oxygen sensor. It measures the amount of oxygen in the exhaust.
2. All vehicles have an 'ideal ratio (mix)' of air to fuel. Think of the 'mixed drink' scotch-and-soda.
3. "System Too Lean" = light on the fuel/heavy on the air. Think of scotch-and-soda, light on scotch/heavy on soda.
NOTE: "System Too Rich" = heavy on fuel/light on air. Think of 'scotch-and-soda, easy on the soda'. I hear the drink is good - I'm sure it has a good burn - but the fuel/air mix version means you're burning excess fuel!
The blessing of computers ('brain boxes') in vehicles, is that they are great message-takers and give you those messages in the form of codes. The curse is, you have to know not only what those codes represent, but also what they truly mean. Ok, I heard that collective, "Huh?!" Read on; you will see what I mean.
Let's review...
My client called in for pricing on an oxygen sensor, based (partially!) on a code somebody, somewhere had retrieved from his F150 for him. But the code he gave me was for a 'lean' system condition on one side of his engine. After further discussion, another code mentioned the other side of his engine was running 'lean' as well. What are the chances of him needing two oxygen sensors at the same time, with codes that don't mention them being bad?
Most vehicles driving around these days have either three or four oxygen sensors. The F150 in this scenario had an engine with eight cylinders, shaped in a "V" with four cylinders on each side. Hence, the term "V8" applies. In the V-shaped engines, each half of the V has its own exhaust manifold, which remain separate until they merge in the exhaust pipe system. Each exhaust manifold (the 'banks' referenced above) has an oxygen sensor, who's job is to report on the oxygen levels (or air/fuel mixture) in that specific side of the engine. Since these sensors are always before the catalytic converter(s), they are labeled 'upstream'. Sensors appearing *after* the converter(s) are labeled 'downstream'. [If you consider comparing the flow of exhaust gas to the flow of liquid water is odd, you aren't alone!]
Now, the gentleman's truck was giving codes about 'lean' burning conditions. Based on what information? Well, that would be the measurements provided by his two 'upstream' oxygen sensors. They weren't faulty; they both detected a decreased fuel presence in the exhaust mixture, and reported that situation accurately. His engine was being starved (to a degree) of fuel!
After further discussion, the gentleman revealed that he hadn't changed his fuel filter in about three years. I advised him to start with a fresh filter - and to replace it every 12- 24 months, depending on driving mileage/conditions. He also admitted that he hadn't ran a fuel treatment in almost as long, so I recommended he run *one* through at the same time. With all of the build up of contaminants in his filter alone, there may also be build up in the rest of the fuel delivery system. But, using fuel cleaners too often - or too high a concentration, or even worse, both - can wreak havoc on your fuel pump. So, I cautioned him to use only one treatment and then assessing the progress from that point. I even offered to clear those codes off for him when the repair was done, so he could have a 'fresh start' to his computer's message system.
The gentleman expressed gratitude for my thoroughness in solving his true problem, and asked what the store hours and my hours were. It sounds like I have a loyal customer waiting to see me tomorrow morning. Hmm, I wonder if he read any of my earlier blog posts...
Drive aware, Readers!
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