CEL after oil change and gas

[Skye]

Energy in a battery is stored on the negative (-) side; this is where the excess of electrons, the force is.

Energy flows from areas of higher concentrations to lower. In the example of a battery, from (-) to (+).

Given an electrical circuit, electrons will leave the (-) side and make their way back to (+).

The main cable attached to the negative (-) battery terminal should always be removed first.

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[jd_cobra]

Wound up clearing the code and filled the tank up with 93 from another station along with gas treatment.

Cruised around for a few hours and would stop and cycle the car off for 5 minutes at a time every half hour or so and the scanner hasn’t detected the code and is reading all 4 banks again.

Glad I only put 5 gallons in to begin with and hopefully crisis is adverted. If not, I’ll just have to rebuild and do a heads/cams setup. I loathe having to deal with dealer and warranty shit.

 

[Snakebyte]

The negative IS the ground. Always pull the negative first. If you don’t pull the negative and put a wrench on the positive terminal and it touches anything metallic in the engine bay you’ll be pulling pieces of the wrench and/or battery out of your face.

Been there, done that years ago, and learned from my mistake. I had a battery explode in my face, as the the spark at the positive terminal ignited residual hydrogen sulfide gas (generated by lead cell batteries when charging) resulting in battery acid blown in my face. Thankfully I had glasses on, protecting my eyes, and I was able to quickly clean the acid from my face. Scary!

BTW...you'll notice that you don't get the sparks when you take the negative off first.

Once removing the negative cable away, intentionally place it from the battery altogether so you don't inadvertently touch the positive terminal with that cable.

 

[ice445]

Wound up clearing the code and filled the tank up with 93 from another station along with gas treatment.

Cruised around for a few hours and would stop and cycle the car off for 5 minutes at a time every half hour or so and the scanner hasn’t detected the code and is reading all 4 banks again.

Glad I only put 5 gallons in to begin with and hopefully crisis is adverted. If not, I’ll just have to rebuild and do a heads/cams setup. I loathe having to deal with dealer and warranty shit.

Glad you're back to normal. Luckily it was only 5 gallons and not a full fill up.

 

[Skye]

@jd_cobra ,

Glad to read everything worked out, there was no damage and you were able to fix without a trip to the dealer. .

 

[jd_cobra]

Been there, done that years ago, and learned from my mistake. I had a battery explode in my face, as the the spark at the positive terminal ignited residual hydrogen sulfide gas (generated by lead cell batteries when charging) resulting in battery acid blown in my face. Thankfully I had glasses on, protecting my eyes, and I was able to quickly clean the acid from my face. Scary!

BTW...you'll notice that you don't get the sparks when you take the negative off first.

Once removing the negative cable away, intentionally place it from the battery altogether so you don't inadvertently touch the positive terminal with that cable.

I always placed them on a couple of folded microfiber towels so would accidentally touch anything or slide off. Don’t know if that’s safe but at least it won’t touch metal.

Glad you're back to normal. Luckily it was only 5 gallons and not a full fill up.

I think that definitely saved my ass for sure.

 

[jd_cobra]

@jd_cobra ,

Glad to read everything worked out, there was no damage and you were able to fix without a trip to the dealer. .

I’m definitely grateful, lol. I was debating on whether to order a “fuel dump” tune or to fill it up with a additive but I honestly think I got lucky doing it the way I did.
I think the tune route to empty the tank/lines would have been the way to go but I figured I’d be safe since it wasn’t flex fuel and I was switching fuels from 93 to E85 or vice versa.

 

[ZXMustang]

That's an interesting theory you've got there, you're literally the only person I've ever heard that says this. How can you short to ground when the battery negative IS the ground? Power from the battery has no reason to even try to flow with the negative disconnected

Exactly. Point proven. That’s what I’m saying. If you pull the positive and touch it to the body, that will do nothing. If you pull the negative and touch that to the body you are just regrounding the battery and powering the car again. Why chance that? Pull positive and if it touches anything it’s not going to matter?

 

[sk47]

Exactly. Point proven.

Hello; How about this. You keep on detaching and reattaching the pos cable first with the neg staying attached on your own car(s). Please give any bystanders some warning and if we ever meet stay away from my vehicles. You do it your way as it pleases you.
I think you are wrong. Look up the procedure for jumping a car with cables.

 

[Snakebyte]

Hello; How about this. You keep on detaching and reattaching the pos cable first with the neg staying attached on your own car(s). Please give any bystanders some warning and if we ever meet stay away from my vehicles. You do it your way as it pleases you.
I think you are wrong. Look up the procedure for jumping a car with cables.

I realize the battery discussion is off-topic from the OP's original question, but this IS A SAFETY ISSUE needing to be addressed.

Unfortunately Ford no longer gives instructions in the owner's manual on how to connect/disconnect batteries. (At least my 2019 manual avoids the topic.) I'm guessing it is because they fear liability of damage to their computerized systems resulting in a "he said, she said" situation should an owner do an oops.

The principles between charging and jumping are the same, for safety reasons, and for protecting vulnerable electronics in cars.

Anyway, Interstate Batteries has a couple good articles. I even learned something from the first linked article (step 5).
https://www.interstatebatteries.com/blog/official-way-to-jumpstart-a-battery

The second article is well worth reading also.

https://www.interstatebatteries.com/blog/how-to-disconnect-car-battery-terminals-safely

 

[KeyLime]

Exactly. Point proven. That’s what I’m saying. If you pull the positive and touch it to the body, that will do nothing. If you pull the negative and touch that to the body you are just regrounding the battery and powering the car again. Why chance that? Pull positive and if it touches anything it’s not going to matter?

This is so wrong I don’t even know where to begin.

This is a serious safety hazard. Do not mess with the positive terminal while the negative is attached.

 

[melwff]

Exactly. Point proven. That’s what I’m saying. If you pull the positive and touch it to the body, that will do nothing. If you pull the negative and touch that to the body you are just regrounding the battery and powering the car again. Why chance that? Pull positive and if it touches anything it’s not going to matter?

If there is no cable attached to the negative post of the battery how is the detached negative cable going to reconnect to the post by touching it to anything other than the battery? Makes no sense.

 

[Stang 19]

I presumed you checked and re-snug the gas cap? You would be surprised how often a slightly loose gas cap will throw a check engine light because the evaporative emission system is not sealed like it is supposed to be.

 

[jd_cobra]

I presumed you checked and re-snug the gas cap? You would be surprised how often a slightly loose gas cap will throw a check engine light because the evaporative emission system is not sealed like it is supposed to be.

If our cars had caps you’d be correct good sir, lol. You know all of our cars are cap-less right?

 

[melwff]

I presumed you checked and re-snug the gas cap? You would be surprised how often a slightly loose gas cap will throw a check engine light because the evaporative emission system is not sealed like it is supposed to be.

P0171 is not related to evaporative control systems
https://www.obd-codes.com/p0171

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