ethanol causing false check engine lights?

[Car Doc]

I'm going to have to ask my former mechanic (the one that sold out) if he can recommend another mechanic. The check engine light started blinking today and the car was shuttering at lower speeds and not wanting to accelerate. So it is parked until I can get this corrected.

That's a misfire if its blinking anyone with any diagnostic skill at all can fix that one and good idea to let it sit until you get an appointment.

The blinking is to warn you so you dont melt the cat with un-burnt fuel that gets expensive.

 

[2manyrocks]

I talked with a friend in the used car business and he recommended a couple of mechanics.

While looking at the car today, I found a disconnected vacuum line and reconnected it. So far, no check engine light, but I'm not driving it far or fast until I'm sure this was the problem.

 

[ModMech]

2003 Mazda protege (81,000 miles) check engine light is on and the code is reading too lean condition. The shop suggested I might have an air leak at the fuel hose or a vacuum leak. I'm not finding one.

The check engine light on my 2004 Mazda pickup (51,000 miles) came on today showing both the check engine light and a light for an open fuel cap. The fuel cap is tight and I can't find any problems in the hose.

I was told that ethanol fuel has a higher oxygen content. Is it likely that this ethanol gas I'm paying $3.70 a gallon for is causing these check engine lights to go on? It would seem more than coincidence that both vehicles are doing this at the same time.

I did read all the posts and see that there was a loose hose. However, the answer to your question is YES!

The ECM looks at oxygen sensors to determine the oxygen content of the exhaust, this is impacted by the ethanol content of the fuel. It is NOT because ethanol "has more oxygen in it" but because you need more ethanol (richer fuel mixture) than with gasoline. Since the ECM has no way to know the ethanol content, injecting the same quantity of "fuel" results in a "lean" mixture on ethanol blends.

As the oxygen (O2) sensors age they do not respond to the changes in the exhaust composition as quickly, the ECM can mis-interpret this "lazy" O2 sensor as a PROBLEM. What kind of problem? Anything from a leak, to a bad O2 sensor to a bad catalytic converter! All because of a little lazyness of the O2 sensor and ethanol in our fuel.

If I park both fuel injected vehicles and go back to my 1992 Mazda with a carb, what is the ethanol going to do to it?

Nothing good! It will run lean and the ethanol can damage some non-metallic carb parts and wash some types of protective coating off metallic parts.

 

[Bedford24]

If your wife drives your vehicle or complains about a Check Engine Light during Cold weather - women are prone to leave cars running when they refuel - tell them to shut the engine off completely - The Computer will read it as an "Evaporative Leak" and cause the Check Engine light to come on - as to the Mazda - they have bad Intake Gaskets - seen hundreds of Fords with the same engine with the same fault codes - Lean in one bank and Evaporative Leak.