Hoping my fellow forum members could provide some guidance with your experience....

I'm worried I've caused permanent damage to my engine, but am hoping you all will tell me I'm imagining things...

I have a 2001 coupe, 6 speed.

Near an empty tank of fuel, I filled up ~ 1/4 of a tank at a local gas station (not the usual one I go to, which is Sunoco, where I always baby it with 94 octane fuel)...at this place, the highest grade was 91. It's a relatively reputable, big name station in our area.

Headed out on the highway, and within 5 minutes, my check engine light came on. I could also noticeably feel the car seem to stammer occassionally at light throttle. Pulled off the highway, checked the oil, fuel cap, etc, everything was fine, turned engine off and on, and the check engine light was immediately back on.

Travelled to my destination, which was ~ 60 miles away, put in a bottle of fuel injector cleaner and immediately filled up the tank with Ultra 94. 5 minutes later the check engine light went out and car seemed to run significantly better.

My suspicion is that the gas station may have accidentally put regular fuel in their premium tanks (which would be a pretty rare situation I would think) - can't think of any other possibility (I know I put premium in).

Now, when I let the car idle, I hear a light buzzing sound and a light tick from the engine, so I'm worried I've permanently damaged something. Going to take to the dealer today to examine - car is still under extended warranty, but my worry is that if they find out bad fuel was the culprit (as I would suspect the diagnostics may indicate engine knock causing the check engine light to go on), I'm sure any repairs won't be warranty covered - I then have to PROVE to the fuel company their fuel damaged my engine - good luck in getting a claim out of them. Do you think I'm overly paranoid - could travelling on bad gas for ~ 60 miles case permanent damage?

Any guidance would be really appreciated!
Thanks
Jason

 

Shouldn't be a problem. You did what most of us would have done.

 

You may have not fully installed the gas cap sfter the 91 fill.

 

No problem.....91 octane is all we can get here.....never a problem.

 

 

First, you'll want to lookup what codes your car threw. Search this forum for 'dic codes' and you'll find the procedure to make your car display the codes to you. Via your search, you will also find links to the code descriptions.

Your check engine light may have had nothing to do with the gas itself.

For certain conditions, I believe your car must pass the diagnostic test 3 times consecutively before the check engine light will go out - this may be why the light persisted as long as it did.

Look up the codes and you'll have a better idea what went wrong.

It could be the case that something was on it's way out anyway (perhaps an o2 sensor), and the 'bad gas' exasperated the condition.

I wouldn't be concerned that the gas itself did any damage to your engine.

Good luck,
Pete

 

And, if this is the case, the loose gas cap (if loose, that is) could have caused the problem.
Checking codes:

||Turn the key to the ON position, but don't start the engine. Clear any present messages by pressing the RESET button. Hold the OPTIONS button down, and press the FUEL button 4 times. This will get you into the CODES section of the DIC. The computer will automatically display all the codes your car has created. It will cycle through each code every 3 seconds. Any code that ends in H is a history code (something that has occured in the past) but is fine now. Once the computer has finished going through all of it's codes, press RESET to enter Manual Configuration mode. It should start with a module and show "NO CODES" or "# CODES".

To optionally reset the codes once in manual mode, press and hold RESET until it displays "NO CODES". Press OPTIONS to go to the next module. Repeat the steps in this paragraph until you have reset the codes in all the computer modules. NOTE !! Only reset the codes IF you want to - it is NOT necessary to do this.||

Then share the codes with the forum members and they'll be able to give you a better idea. Once you erase the codes, the dealer can't tell what was going on

As for the noises, my guess is they were there already, but you became worried after your experience and then noticed them. Get the codes, let forum members decipher, and then you'll have a good rest tonite

 

WOW! Thanks TopCat (and everyone who replied ) - this is why I love this forum so much - people are so helpful and genuinely interested in helping others - THANK YOU! Will take your advice and retrieve the codes.
Cheers
Jason

 

Woohoo, thanks Topcat - I was able to retrieve the codes using your methodology....

10-PCM P0101H
B0-RFA-U1000H
B0-RFA-U1064H

If anyone would be kind enough to help me decipher what these mean I would really appreciate your help!
Thank you all again!
Cheers
Jason

 

10-PCM P0101H = Mass Air Flow (MAF) Sensor Performance

B0-RFA-U1000H = Class 2 Communication Malfunction
B0-RFA-U1064H = Lost Communication with XXX

The second two can happen for any number of reasons, such as a weak battery or poor ground. I wouldn't worry about these unless they return (you can tell they are not current codes by the presence of the H and no C).

The first one should be self explanatory, and I suppose could be caused by the gas if it was suspect. If the code doesn't return and the car performs normally, it's probably not cause for concern.

Here's the link to the code descriptions:

DIC Codes for 2001 C5

-Pete

 

I wouldn't sweat it. These cars can take 87 octane. That's what knock sensors are for! I just wouldn't make a habit of it.

Dope

 

Sounds to me, you got a load of "watered down" gasoline. Before you get too deep into trouble shooting, hit the car with a couple of bottles of "dry gas". Odds are, that will fix the problem.

I've had this happen a couple of times over the years...Annoying as hell, but certainly not fatal to the car.

 

P0101 sets when the airflow difference between what the MAF sensor measures and what the PCM calculates it should see is more than 50%.

I don't believe the quality or octane of the fuel has any effect on this as it is a measure of airflow before the fuel is introduced and the fact that this occured after the suspect fuel was added is just a coincidence.

Any vacuum leaks including a dip stick that is not fully seated can introduce un metered air causing the code to set. Poor connections, worn or broken wires will also set the code. It could also be that the MAF is going bad or in rare instances, the PCM itself could be faulty

 

I got water in my gas on two separate occasions from two separate fuel stations. One time it was so bad my car would not run until I siphoned all the gas out and replaced with fresh fuel and dry gas. Both times it was from a Sunoco station. I wrote Sunoco a nasty note with my gas card cut in half asking them to pay for repairs. No response, go figure. This was years ago probaly 17-18. Anyway, my belief is that the fuel delivery was made prior to me buying fuel and it stirred up the water and or sediment in the tank and got pumped into my car. For that reason, if I see a truck making a delivery I will go somewhere else for gas.Maybe I'm wrong but it's cheap insurance. I also run a can of dry gas thru all my cars every few months now regardless.

 

Been there, too. No problem. You know where not to stop.

All the best.

 

DRY gas is just rubbing alcohol?

 

Thanks again for your help everyone - I've taken the car in to the dealer to assess what could be making the sounds, but I feel a lot more confident that it's not engine damage from the fuel.
Cross my fingers what they'll find today.

 

You're correct. Gas suppliers (Marathon Oil, Plantation, etc.) tell store owners they should wait 8 hrs after a delivery to sell the gas. Guess what?!?! they sell it anyway (of course), as the truck is offloading even .

The condensation situation occurs in the underground storage tanks at service stations and really accumulates. Some stations are good about pumping it out, but most aren't. Stations that use methanol don't worry about it because the alcohol absorbs the water and pumps it right into the customer's tank. Wo unto the unsuspecting motorist that pulls into a cheap station that's gotten a "bargain" on some fuel that has methanol in there as octane booster.....if the station doesn't regularly use alcohol, guess what? All the water that's collected in the tank gets mixed in with that one 'special' load. Woohoo, I save $0.50 on a tankful of cheap gas!!!!!!!!

Also, check out www.toptiergas.com for some informational reading.

 

Hey man, good luck. Let us know what they tell you, especially before dropping a mess of coin, unless you really, really, really trust your stealership, uh, I meant dealership

 

All very good advice folks, thank you! Just to wrap up, took the car to the dealer and they couldn't find anything wrong. They acknowledged that the fuel pump was indeed making a bit of a buzzing sound, but that 'no repair is necessary at this time'. Translation - let's wait 6 more months till my warranty runs out and it actually dies, THEN we'll do a repair. Oh well, I guess I can see their point, given it still functions. Strange though, because I thought the fuel pumps were in the gas tanks - is there a secondary fuel pump under the hood?
Cheers
Jason