CEL after fuel treatment

[Junkyard_Mad-Scientist]

about 8-10 months ago I replaced all 6 injectors, per recommendations from here I added a fuel treatment into my maintenance regiment. every oil change I run a bottle of Royal Purple Fuel Treatment through the tank, for the duration of this treated tank I drive the car HARD, it almost immediately shows signs of improvement with throttle response and it seems to eliminate light idle and top end fluttering. its made me a believer so I am on my 4th treatment but I have noticed that all but one time after about half the tank has been used I get o2 sensor codes. It would stand to reason that the "gunk" is burning off and messing with the sensor similar to a seafoam treatment, but with how consistent it is I was wondering if anyone else has this happen to them after fuel treatment?

I used to get CEL after hard accelerations frequently when I bought the car, then I did the injectors and it seemed to go away unless the fuel treatment was in the tank. As I said before I drive the car harder than usual while the treatment is in the veins and around half a tank If I go WOT itll pop the o2 Sensors (both banks, sensor 1). anyone else or am I special? am I hurting the sensors or worse the cats?

 

[Joshw0000]

What mods do you have? Is it tuned? It seems like the treatment would essentially create a higher octane fuel and if you're tuned for a certain octane, your car probably isn't optimizing the fuel.

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[Junkyard_Mad-Scientist]

bone stock, spent my tuner money on injectors and tires. I do run 93 so maybe if its acting as an octane booster its going above what it wants to see?

 

[Joshw0000]

That's just my speculation and I'm sure someone has more educated information. I've never run a fuel treatment in mine but from all the claims that RP makes about that treatment, it makes sense to me that it's acting as an octane booster with cleaning properties. I can't imagine that it's boosting the octane level by much (probably 94 at best). And I don't see any disadvantages online from using higher octane fuel. My guess is that your 02 sensors are used to certain readings. With the slightly higher octane / detergents and harsher driving they're seeing less emissions than normal, which is why the CEL goes off after the tank.

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[Junkyard_Mad-Scientist]

That's just my speculation and I'm sure someone has more educated information. I've never run a fuel treatment in mine but from all the claims that RP makes about that treatment, it makes sense to me that it's acting as an octane booster with cleaning properties. I can't imagine that it's boosting the octane level by much (probably 94 at best). And I don't see any disadvantages online from using higher octane fuel. My guess is that your 02 sensors are used to certain readings. With the slightly higher octane / detergents and harsher driving they're seeing less emissions than normal, which is why the CEL goes off after the tank.

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I clear the code usually, I think this time I'll leave it and see what happens.

 

[kryptto]

so I have heard that the additive for some of these treatments can cause cat fouling. glad i don't have mine. I have tested 93 with an additive, when sending logs to brad he "saw" the additive in the logs by the timing adjustments, however I would ask if this is O2 related? MMT I believe is the additive. I would personally use non MMT for just cleaning and keeping carbon buildup. Seafoam, Techron additives, those that clean and help with carbon buildup is my suggestion.

https://www.sae.org/publications/technical-papers/content/770655/

 

[Junkyard_Mad-Scientist]

I used to be a strong advocate for seafoam but I heard using it on a regular basis will cause cat fouling so I only use it sparingly and mainly on my "off road" vehicles like my registered and insured F150. unfortunately I still have my cats on the taurus and with Floridas spike in home insurance I wont be swinging any catless downpipes any time soon. I grabbed the RP for 2 reasons, heard lucas fuel additive horror stories (ironic, I still use the oil additives), and it had "essential for GDI engines" on the bottle specifically claiming the breaking down of carbon deposits associated with our fuel injection. I figured maybe it cleans differently in a way that wont foul the cats so I went for it but the consistent CEL warranted a post. I can dump a can of seafoam in the tank next time if you believe it will be more effective and/ or less harmful. I trust your research

 

[kryptto]

I used to be a strong advocate for seafoam but I heard using it on a regular basis will cause cat fouling so I only use it sparingly and mainly on my "off road" vehicles like my registered and insured F150. unfortunately I still have my cats on the taurus and with Floridas spike in home insurance I wont be swinging any catless downpipes any time soon. I grabbed the RP for 2 reasons, heard lucas fuel additive horror stories (ironic, I still use the oil additives), and it had "essential for GDI engines" on the bottle specifically claiming the breaking down of carbon deposits associated with our fuel injection. I figured maybe it cleans differently in a way that wont foul the cats so I went for it but the consistent CEL warranted a post. I can dump a can of seafoam in the tank next time if you believe it will be more effective and/ or less harmful. I trust your research

See if I go to RP site - they do not list the additives. My suggestion read the label and look for MMT, avoid it except if you are trying to troubleshoot poor octane gas issues. Just my 2 cents.

 

[Tbird6]

I try to run additives with a high PEA content such as Techron once in a while. If interested there is a lot on PEA over at bob is the oil guy forum.

Does it help? I don't know and can't say I have noticed anything either.

Why were the injectors replaced?
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.
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[Junkyard_Mad-Scientist]

I try to run additives with a high PEA content such as Techron once in a while. If interested there is a lot on PEA over at bob is the oil guy forum.

Does it help? I don't know and can't say I have noticed anything either.

Why were the injectors replaced?
.
.
.

I had a misfire on one cylinder consistently and after ruling everything else out I replaced the injector, a month later 2 more started so I replaced the other 5. Haven't had a misfire since and from my diagnosis a couple of the injectors had been replaced at one time, non matching set.

I ended up clearing the code since it wouldn't go away on its own, hasn't come back yet so I'm certain it's the additive, I'll definitely look into the chemical make up of these for the next treatment. I can say that I do notice a difference when it's been a while between treatments, the idle alone is smoother.

 

[kryptto]

difference when it's been a while between treatments, the idle alone is smoother.

my biggest issue running tuned. If the gas is a bit off or since not everyone loads up on 93 at the station, add in it can start getting stale in my tank from sitting, rough idle can happen to me for sure. I noticed the more tuned my car is the less acceptable the lesser than optimal standards cause the car to react adversely.

Can this be true for a non tuned car, I am sure, I never recall my car EVER having anything but a fluctuating idle.

 

[Junkyard_Mad-Scientist]

my biggest issue running tuned. If the gas is a bit off or since not everyone loads up on 93 at the station, add in it can start getting stale in my tank from sitting, rough idle can happen to me for sure. I noticed the more tuned my car is the less acceptable the lesser than optimal standards cause the car to react adversely.

Can this be true for a non tuned car, I am sure, I never recall my car EVER having anything but a fluctuating idle.

I often wonder what's an acceptable amount of flutter. I'm a stickler for smooth operation (unless it's a good cam lope from a v8) I have to remind myself of a few truths. 1) the car is not new, it will have its quirks. 2) new parts are often less than perfect 3) gas is probably a factor. And 4) the radio works great. I burn a tank of 93 every week just commuting, I've had bad batches but with how quickly a situation with these cars can turn ugly I get nervous when things are less than perfect. It it another injector, another coil pack, is water going in the cylinder, etc.

 

[rickoshay]

I used to be a strong advocate for seafoam but I heard using it on a regular basis will cause cat fouling so I only use it sparingly and mainly on my "off road" vehicles like my registered and insured F150. unfortunately I still have my cats on the taurus and with Floridas spike in home insurance I wont be swinging any catless downpipes any time soon. I grabbed the RP for 2 reasons, heard lucas fuel additive horror stories (ironic, I still use the oil additives), and it had "essential for GDI engines" on the bottle specifically claiming the breaking down of carbon deposits associated with our fuel injection. I figured maybe it cleans differently in a way that wont foul the cats so I went for it but the consistent CEL warranted a post. I can dump a can of seafoam in the tank next time if you believe it will be more effective and/ or less harmful. I trust your research

I've been using the Lucas fuel additive in my 2011 (non PP) and haven't seen any ill effects so far. I bought the car in March '24 and started using the Lucas soon after. I'm retired so I don't drive much, probably have put 1000 miles or so on it. Now I'm wondering about the 'horror stories' that i haven't seen yet. I also run the Lucas in my old 1992 F350 and it seems to make it run much better, smoother idle, easier starting, etc.

 

[kryptto]

I've been using the Lucas fuel additive in my 2011 (non PP) and haven't seen any ill effects so far. I bought the car in March '24 and started using the Lucas soon after. I'm retired so I don't drive much, probably have put 1000 miles or so on it. Now I'm wondering about the 'horror stories' that i haven't seen yet. I also run the Lucas in my old 1992 F350 and it seems to make it run much better, smoother idle, easier starting, etc.

techron additive, or as @Tbird6 said - PEA, too often these modern cars are about managing carbon buildup, not so much older FI and carb system issues.

 

[kryptto]

Yes, Techron is a PEA-based fuel additive. It is a product of Chevron and is widely recognized for its effectiveness in cleaning fuel systems and removing carbon deposits.

Techron's active ingredient is polyether amine (PEA), which is a powerful detergent that can break down and remove carbon deposits from various parts of the engine, including intake valves, fuel injectors, and combustion chambers.

Using Techron can help improve engine performance, fuel economy, and reduce emissions by keeping the engine clean and free of deposits.

 

[rickoshay]

techron additive, or as @Tbird6 said - PEA, too often these modern cars are about managing carbon buildup, not so much older FI and carb system issues.

Thanks for the info, I did read somewhere about carbon deposits being an issue. I realize that every car & situation is different, but how often should the techron be added generally?

 

[kryptto]

Thanks for the info, I did read somewhere about carbon deposits being an issue. I realize that every car & situation is different, but how often should the techron be added generally?

as the Chevron site states - you can buy their gas and get a much more diluted concentration of PEA - or follow the bottle for amounts to add. Ours is 19 Gallons

 

[luigisho]

I had a fuel sending unit in my '14 f150 that stopped reading fuel level at the gauge. 1-2 tank treatments of techron and that thing worked again. This was 2+ years ago. Must have dissolved what was built up in there. This is full immersion though. I still use that tank treatment a few times a year. Make sure the ratio to gallons of fuel in the car is correct.

 

[rickoshay]

I had a fuel sending unit in my '14 f150 that stopped reading fuel level at the gauge. 1-2 tank treatments of techron and that thing worked again. This was 2+ years ago. Must have dissolved what was built up in there. This is full immersion though. I still use that tank treatment a few times a year. Make sure the ratio to gallons of fuel in the car is correct.

If I'm not mistaken I think the ratio is 1 oz/gallon. My F350 is OK but I think I'll try a 20 oz bottle in the sho, which is a 19 gallon tank.

 

[rickoshay]

as the Chevron site states - you can buy their gas and get a much more diluted concentration of PEA - or follow the bottle for amounts to add. Ours is 19 Gallons

No Chevron stations around me that are close or convenient but since the car sits a lot I have been using non-eth fuel probably 75-85% of the time along with the Lucas treatment. I'm going to try a 20 oz bottle once I run the fuel that's in it through.