Fuel Additives and a check engine light

[INTJ]

You guys ever get a check engine light while using cleaners in your gas? I just put in 6 ozs of Lucas in 30 gallons of fuel and about 1/3 way before empty, my CEL came on. I pulled a P0175 code, Bank 2 oxygen sensor running rich. This is the one before the cat on right side 4.6 Ford Modular engine. I turned the CEL off via a scanner. So far it's staying off. In the meantime I bought another. My dad recently did an STP additive and he got a CEL, and it stayed on, and I turned it off with my scanner, but it popped back on. He ran that tank out and the light wandered on an off on next tank, but it looks like it's off now. Funny thing is we never had this before, but we both have a decade on our vehicles now. Do you think the cleaner is affecting these old sensors directly, or is it cleaning the stuff and is being burned, causing the CEL? Thanks.

 

[91344George]

Possible that the make up of the additives make it a bit more difficult for the ECU mapping to adjust quickly enough to the changes.

 

[Vikas]

If you have been here long enough you would not be using Lucas

 

[HTSS_TR]

The only fuel additives I use are Chevron Techron and Redline SI-1, never have CEL while using it. Why did you use Lucas additive ?

 

[JavierG]

I use Techron or Regane, depending on their sale prices. Both are good.

 

[Chris142]

Six ounces in 30 gallons of gas had nothing to do with a check engine light

 

[RamFan]

I used this in my Mom's Sebring and the CEL light when on a couple miles later, shut off after another 30 or 40 miles. Its the only additive I've ever had that happen with.

 

[INTJ]

Originally Posted By: 91344George

Possible that the make up of the additives make it a bit more difficult for the ECU mapping to adjust quickly enough to the changes.

Yeah, George that's what I was thinking. They are probably getting "lazy" from age. To the questions on why Lucas: Some higher end cleaners are abrasive/aggressive on top end and they recommend the use sparingly... something published by them. The Lucas seemed mild and I tried a bottle, but it's unknown whether it worked. I Sea Foamed it once with the goose necked straw in throttle body, and this decarbonized those heads; you could see it blast out the exhaust on hard throttle. Auto Zone counter people try to upsell Lucas on checkout, and claim better gas milage with it, but I didn't see it.

 

[Durango]

Originally Posted By: INTJ

You guys ever get a check engine light while using cleaners in your gas? I just put in 6 ozs of Lucas in 30 gallons of fuel and about 1/3 way before empty, my CEL came on. I pulled a P0175 code, Bank 2 oxygen sensor running rich. This is the one before the cat on right side 4.6 Ford Modular engine. I turned the CEL off via a scanner. So far it's staying off. In the meantime I bought another. My dad recently did an STP additive and he got a CEL, and it stayed on, and I turned it off with my scanner, but it popped back on. He ran that tank out and the light wandered on an off on next tank, but it looks like it's off now. Funny thing is we never had this before, but we both have a decade on our vehicles now. Do you think the cleaner is affecting these old sensors directly, or is it cleaning the stuff and is being burned, causing the CEL? Thanks.

INTJ, I never tried Lucas products so I can't say. The only additives I use is Chevron Techron or Gumout "Regain" and never had my CEL light come on. Durango

 

[surfstar]

Originally Posted By: Vikas

If you have been here long enough you would not be using Lucas

There's nothing wrong with Lucas UCL. Overpriced unless you get the quart or gallon size, though.

 

[Vikas]

In general, many of the CEL start coming on randomly before becoming more persistent. It is true with O2,Cat converter, Evap, EGR. They will come and go but eventually they start coming back all the time. If you have a good scanner, you can look at the Mode 6 test (and have manufacturer's decoding ring) and locate the borderline results. This does not work every time but sometimes you can pinpoint a soon to be failing component. It is possible that fuel additive usage and CEL coming on was just a coincidence. When it comes to good fuel additives, Lucas is not in running. You have lot better choices with Techron, Regane, Redline. 3M etc. - Vikas

 

[ahoier]

Had it happen once with my 08 Optima Added a bottle of Chevron Techron concentrate to the tank, drove around a good week or so.....If I recall, it was about 1/2 way through the tank, the CEL "tripped"....on my way home one night....all the parts stores were closed. Forgot all about the CEL the next day, and drove the car to work the next day, on the way to work, on the "acceleration lane" on the highway, I put pedal to the metal and the light blinked a couple times, and then it went off :P Asked my mechanic about it, and he said most likely the Techron (PEA based....) flaked off some loose carbon, that hit the o2 sensor, and triggered the light.....well, when I went full throttle on the highway, it burned it up

 

[INTJ]

Originally Posted By: Vikas

In general, many of the CEL start coming on randomly before becoming more persistent. It is true with O2,Cat converter, Evap, EGR. They will come and go but eventually they start coming back all the time. If you have a good scanner, you can look at the Mode 6 test (and have manufacturer's decoding ring) and locate the borderline results. This does not work every time but sometimes you can pinpoint a soon to be failing component. It is possible that fuel additive usage and CEL coming on was just a coincidence. When it comes to good fuel additives, Lucas is not in running. You have lot better choices with Techron, Regane, Redline. 3M etc. - Vikas

Thanks for those. The scanner I have is dated, and I'm 8 years behind on an update. (They want 50 for the USB cable.) So far with the stock software, "mode 6" is above and beyond it. I'm familiar with the concept of the ECM hunting for stoichiometric center at 14.7, indicated by .5 volts on the sensors, and I see two of them ranging in a sweep; the other two are sluggish/ very slow. I'd guess the "slow" group are behind the cats? And these monitor the cats in-and-of-themselves as to whether they are operational/or functional? Bottom line, in closed loop I'm aware of a frozen or sluggish voltage sweep on pre cat O2 sensors, is showing them to be malfunctioning. I've used Lucas before without the CEL popping up and it could coincidental with light, or maybe it's marginalizing an already weak O2 sensor. Interesting stuff, and I'd like to find some good information on these more technical points to brush up more on this subject.

 

[Clevy]

Originally Posted By: Vikas

If you have been here long enough you would not be using Lucas

Yup. You coated the o2 sensors with that junk. It actually helps carb'ed engines get minutely better fuel efficiency however anything with an o2 sensor will experience negative effects sooner or later. Might as well use 2 stroke oil. Cheaper and achieves the same result.

 

[Vikas]

You want the post cat sensors to be very sluggish. Your scanner most likely does not have thar mode

 

[91344George]

Originally Posted By: Vikas

You want the post cat sensors to be very sluggish. Your scanner most likely does not have thar mode

This. On many vehicles the POST cat O2 sensor doesn't do any active work instead it monitors the efficiency and mixture coming from the cat that is a result of the upstream O2 sensor. Usually the monitoring O2 is programmed to be a bit delayed in its response to trouble for an occasional variation, like if you use a gas additive or the like.

 

[INTJ]

Originally Posted By: 91344George

Originally Posted By: Vikas

You want the post cat sensors to be very sluggish. Your scanner most likely does not have thar mode

This. On many vehicles the POST cat O2 sensor doesn't do any active work instead it monitors the efficiency and mixture coming from the cat that is a result of the upstream O2 sensor. Usually the monitoring O2 is programmed to be a bit delayed in its response to trouble for an occasional variation, like if you use a gas additive or the like.

Yeah, that's what I thought. I live in an area where all motor vehicles have to get an emissions test every 2 years. Odd number makes go every odd year and so on. I'm '02 and am due in an even year and in April I go to get plugged in there at the ODII port. If the cat failed the CEL is triggerd via the catback sensor. No need for a sniff/emissions test via exhaust gas.... all self contained in ODII. And thanks Durango and all for the input on fuel cleaner brands.

 

[CharBaby]

Almost every time I put in a FSC in my wifes '01 Lexus RX-300, we get a CEL/VSC light on the dash. Has always been this way. The code# always come up with one of the A/F ratio sensors(Bank 1 Sensor 1 or Bank 2 sensor 1). The next fill up of gas and the CEL goes away.