Rocket Dawg

2011 2.2 engine. Just filled up with E-85 which took over 12 minutes, gas pump was slow as molasses In January, The next day it started and shook like a misfire which cleared up within seconds, ( 2 to 3 seconds) Plus there was a slight smell of gas inside the car. It's cold out ( 20 degrees ) . Car runs good , no codes, Cant wait to burn this garbage fuel out of the car and go back to regular gas. I cant explain the smell of gas inside the car. Maybe the slow fill up caused the evap cannister to take on gas? The stumble at start up is cold engine only., warm engine its fine. Still have 1/2 a tank to get rid of. I've used E85 a few times. Its difficult to find around my place.. Never had any issues with it. Any suggestions? thanks

Oldblue

I’ve never run ethanol in my HHR’s , I’m sure someone will chime in soon. I think PulpFiction might have the cure for you.

Rocket Dawg

Spoke with my mechanic and he said to try a purge valve solenoid. About $32 and easy to get at. It's on the top side of the motor. He believes its running rich at start up , hence the stumbling at start up and the smell of gas. If he's right, I'm gonna send him some chocolate chip cookies and a $50 bill. If he's wrong he gets the car to fix it. He suggested to get that E-85 out of the car and never use it again, it causes more trouble than its worth unless you use it all the time which I cant because it isn't readily available in our area.. I'll keep ya posted.

PulpFriction

Before you start scattershooting parts, read this. Sorry, long, I know, but try to get through it.

There is nothing wrong with E85 fuel. It’s really good stuff that burns cooler and cleaner. And your car is actually rated at a high HP with E85. The problem is that it’s difficult for the car to figure out what ethanol % is in the tank.

First thing to know is that E85 isn’t 85% ethanol. It’s anywhere from 51-84%. And in cold seasons they’re supposed to sell a blend at the lower end of the range because a high % can in very cold weather cause hard starting and problems getting adequate cabin heat. Retailers are even advised when cold weather arrives to “blend down” their left-over “summer” blend by mixing it with regular. Yeah. That’ll happen.

Did you turn off the motor when you fueled it? You’re supposed to do that anyway, but apparently the car needs to be turned off at fueling to realize that the ethanol content may have changed. (Credit for this explanation goes to Donbrew) There is no ethanol sensor, per se. The computer notes an increase in the tank (triggered by an increase of about 3 gallons) and checks the a/f via the O2 sensor and calculates the ethanol %. Ethanol needs a very different a/f ration so if it gets it wrong you have trouble at startup because O2 sensors are useless cold and can’t help the computer correct the a/f. As soon as the car begins to warm up the situation should improve as the car corrects. (Look up “open loop” and “close loop” in the context of ECM’s.) When the computer sees that the necessary correction is excessive it will set a code.

If everything is working correctly, refueling with at least 3 gallons (engine warm and off) should trigger the car to adjust a/f at startup for the new ethanol %, and you should be able mix and match and switch between regular and E85 willy nilly.

BUT it doesn’t always work. Ask me how I know. I think possible contributors to computer confusion about ethanol % are fuel/vent system leaks, iffy O2 sensor, frequent very short trips that don’t warm the engine up, and a programming bug. Your problem with slow fuel uptake could mean trouble with the vent system, so a purge valve or vent valve isn’t totally senseless but I wouldn’t rush to it. Would double check for fuel and vent system leaks first, and sample the fuel in the tank and test it for ethanol %, and scan the car and see what the computer thinks it has, and go from there.

Any codes at all, even if no CEL, even pending, even seemingly unrelated?

I had a P0172, probably the opposite problem from yours. My car, also 2011 2.2L, never got E85 but thought it had over 50% ethanol in the tank. Somewhat different situation, but it led to a bit of research on this.

Oldblue

Thanks for the explanation, but I have a question, if the fuel read after adding more then 3 gallons to the tank is incorrect, setting a code in your case P0172. As you stated there’s no sensor in the tank testing the alcohol level, the O2 sensors read exhaust levels after warm up. Then how come a battery lobotomy doesn’t reset the ECM back to factory settings, the alcohol readings remain. As you indicate there could be a problem with the vent or purge valve, or leaks in the fuel or vapour lines. But still a lobotomy a full 30 to 45 minutes lobotomy doesn’t reset the readings to factory?
I’ve seen where members have changed both O2 sensors, both vent and purge valves, cleaned injectors, throttle body and still the incorrect readings, the computer has to be reset with a scan tool. Hmmm, perplexing isn’t it.
seems a waste of perfectly good parts . Even to run out the fuel and refill the tank , engine turned off and all.
Perhaps I’m not getting something, that this phenomenon just is stubborn, and our dealership folks are to far out of the loop to reset the % , they don’t even know about it in most reports.
I called my GM guru, she’s very very educated in all things Scan II , in her 15 years of experience with GM computer diagnosis and repairs, she has never seen this problem. Could it be due to very little E85 availability?
Some have reported, they have never put a drop of it in their HHR fuel tanks .
This is the confusing part. Something must set off the 1st O2 sensor or both. I would think that should set a P0420 catalytic converter code.
Interesting read, thank you, hopefully the BlackSwan won’t suffer this problem. But I know now where to look if it does.

Rocket Dawg

It took 15.3 gallons of E85 which is weird because the low fuel warning just came on and it has never taken more than 14 gallons. We are still burning up that tank of gas. I put a purge valve solenoid on 2 days ago. ( $32 and a very easy job, less than 5 minutes) Fired it up and it ran perfectly. But it was inside my heated garage. The next morning it started up and stumbled again ( slightly) and cleared up with very little smell of gas. Almost zero smell. (19 degrees outside) Now i cant figure out if the solenoid helped or the temp difference was the difference. 2 days before hand it started and I saw a fresh gas drip on the driveway ( in the snow) from the front side of the engine, pretty much dead center, about a table spoon worth.( about 11 degrees out) Popped the hood and could not locate the source. The colder it is, the more it does it. If the outside temp is above 27 or so, it will not have any symptoms. I turned off the motor while re-fueling. I'm hoping the E85 is the summer version as the pump was very very slow. Most people would give up and just put the 87 regular in it, so that could be the culprit here. Thanks for the detailed response. I've researched this and no one has come up with a solution. Many others have had a similar issue. Your answer seems to be the best one out there. If others had this problem solved, they never responded back with their findings. Today it will get a fresh tank of regular gas. gonna run the remainder out. The temps are going up for a few days but later this week the bitter cold returns, so I will report back with my findings. One question for ya, would the extra slow filling process cause gas to fill the evap cannister back by the tank? And explain the 15.3 gallons it registered on the pump?

Oldblue

Doubtful, you just burned off more of the fuel load then you thought. At the low fuel notice, I fill up and take on 15.2 to 15.5 gallons. (Equivalent to conversion from litres)

PulpFriction

I don’t think P0172 is telling you the ethanol % is wrong per se, it’s telling you the car is surprised by the large reduction in fuel (“trim”) needed to get an acceptable burn once closed-loop temperature is reached. One explanation would be if the computer thinks there’s 85% ethanol in the tank and it’s really 10%, WAY too much fuel would be fed at startup, and then situation would be undetected as long as is remained in open-loop.

Can confirm the lobotomy did not change the ethanol setting. Kinda makes sense, I suppose. It’s not an error code. What should it reset it to? If the tank is full of 85% ethanol, resetting to zero would be a disaster.

Donbrew explained how the car figures out the ethanol content in one of the P0172 threads.

There have been some common denominators in the cases I ran into (but not all in every case, not even close): Failure to shut off engine at refueling, frequent very short trips, fuel/evap system leaks or malfunctions, onset of cold weather.

Note in this case the trouble the OP had getting the tank to take fuel. I don’t remember exactly what how the problem works but it’s an evap system problem, right?

Something in the back of my mind says there was a TSB in this.

I am allowing for the possibility it’s a programming bug, and it so rarely cause a problem that they either never caught it or decided it wasn’t worth the trouble to address.

PulpFriction

I don’t remember where I read about the cause, and never really understood the exact mechanism for the slow filling problem, but I think it’s an evap system problem. I need to look into it because I have an HHR SS with that problem.

Oldblue

The slow fill of fuel is attributed to the EVAP canister it may have fuel in it or other dirt from over filling the tank , topping off causes this, the EVAP tank may need to be cleaned out or replaced. Something to do with air now allowed to equalize pressure as the fuel fills the tank, causes the gas pump nozzle to shut off.
This is why I never go past that fist click when the nozzle shuts off. Even though my brain says , there’s lotsa room, go ahead , fill it up!

I would think the parameters of the flex fuel system would reset which ever way after a battery lobotomy, but nothing changes in the fuel trim , cold start or hot start. The O2 sensors should see or smell the difference.
Si what if it’s the cold start? Could a corroded original CTS be the culprit, giving false readings ? Hmmmm.


Like this, coolant temperature sensor? Could the black gunk in it insulate or isolate the correct coolant temperature readings? Telling the computers it’s cold! More fuel please!!!