jimpennjr

Dealer wants to drop the gas tank on my 09 HHR. It has had a p0172 (running rich) code for the past 2 months. The conclussion they have come to is contaminated gas, water in the gas. My mpg's have dropped, but there is no noticeable drop in the way it runs. No sputtering, stuttering, or stalling. I'm at a loss. They want $570+taxes to drop and drain the tank (which is full). Can water in the gas cause the running rich code without any other symptoms? Will running a tank of E85 clear the water or maybe even a lot of dry gas? I always use the same station and I am baffled on lhow the water got in there in the first place. Last Sunday when I drove to work the CEL actually went off on its own on the way to work, but of course came back on on the way home.
Yes I used the search function with no luck, but if you know anything that might be useful, please reply or message me.
Thanks in advance, Jim (jimpennjr)

db/sb

If there is no change in the way it runs why not add a 'gas drying' additive like Iso-Heet, drive until you need gas again and see if that clears is up.

whopper

What else have you or the dealer done to diagnose the p0172? Did you google the code at all: ie - http://www.obd-codes.com/p0172 .

My bet would be to go down the list from the info in the above link, starting with the MAF sensor inspection/cleaning.

Snoopy

Jim......

I do not know if it can be done with the HHR BUT.....................

I recently saw a chemical test that determines if the gas tank is contaminated with water. It is essentially a "chemical test strip" that is inserted in the gas tank, with a special wand (although I don't see why a sample couldn't be taken from the fuel rail, for example). The strip turns color and is measured against a predetermined scale. A "trifle" is allowable. The rest require certain procedures to repair properly. It was at a Lexus dealer.

If the dealer needs to drop the tank, I would get some type of guarantee for the repair. Exploratory parts replacement is not acceptable....JMO

Lucky

Strange things can happen but I have trouble understanding why water would give a rich code if anything I would think it would set a lean code. I agree with snoopy a fuel sample should be taken and tested before just tearing into the gas tank.

donbrew

Will they GUARANTEE a fix for that price, or is this a fishing expedition? Sounds like they don't know what's what, unless you are leaving a whole lot out.

E85 will exacerbate a water in the fuel problem. That is one of the drawbacks of E85, it is very hydrophyllic (loves water). You should only use E85 if you use a tank full or so a week.

Fuel driers are basically alcohol, but that is only adding a tiny bit of alcohol to a tank of straight gas. The alcohol combines with the water and gets burned in the combustion chamber. E85 is 85% alcohol already, when it sucks up water you get real water in the injectors. E10 is only slightly more than adding a bottle of rubbing alcohol to a tank of "gas". You should not "need" a drying agent in E10.

High School chemistry; Remember pouring 6 ounces of alcohol into a full glass of water without an overflow?

843de

There has to be more to the story, like has the MAF been cleaned and inspected in the two months since the CEL and symptoms cropped up?

I can't buy the bad fuel diagnosis/guess, in two month's time the bad fuel (if any) would be diluted by subsequent fill ups.

And it's not displaying typical "bad fuel" behavior, in the OP's own words..."no sputtering, stuttering, or stalling", all of which you would expect if the injectors were fed a slug of water contaminated gas.

I concur with Don, the dealer is fishing or guessing at their customer's expense. Take it somewhere else at the very least.

jimpennjr

Cleaned MAF when code first appeared. I will clean it again tomorrow. I have a full tank of 87 in it now. Gonna run it dry and try the dry gas. Hopefully that'll do the trick. Keep the ideas coming.

donbrew

Did you clean the MAF with MAF Cleaner, while being vigilant to not touch the wires? And then assuring that it was plugged back in correctly?

Did anybody consider looking at the HO2 sensors and the flex pipe? The flex pipe or some other exhaust leak between the HO2 sensors is more likely to cause p0172.

jimpennjr

Used MAF cleaner. Was careful when cleaning.