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Some advice requested before I give in to my inner urge

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sd80mac7204

sd80mac7204

Jedi Warrior
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...and set this car on fire.
pontiacsecondhome.jpg

My "new" car is a 2006 Pontiac G6. The engine light was on when I got it and a quick code check indicated a "major evap leak". I replaced the broken fuel cap and reset the code. As time went on the car would enter into a non-start condition if I stopped somewhere for a few minutes and tried to leave again (ie:getting gas) and on occasion would stall at stop signs but it did not trigger the engine light. A week after I replaced the fuel cap, the light came back on. Codes said "major evap leak", "lean bank one", and "lean bank two".
As I don't have the equipment to test evap leaks in depth, I took the car to the local Chevy dealer of whom I'm pretty good family friends with the owners. Evap leak was traced to the purge solenoid on the back of the engine, easy fix. When they reset the codes, the lean codes didn't come back.
I ran the car 2 days and the stalling and non-start came back as well as the engine light....."lean bank one""lean bank two"... ugh... Back to the shop. They cleaned the throttle body and reflashed the computer. The next day... non-start and engine light again.
This time it was determined that the fuel pump was getting weak and wasn't keeping up with engine demand when under acceleration. So the car went in for surgery again on Thursday night and was ready for pick up last night. I paid for the car then took off for home, followed by my ride to the shop. 2 miles later... SURGE...hiccup... Engine light!...stall...
Once I got the car started again, I turned it back around and returned it to the shop and launched the keys through the mail slot.
When I paid the bill, the shop owner said that if the pump didn't fix the problem "the next repair will be on" him. I told him that if I had to bring the car back to him again that a new Impala better be on him.
I'm really frustrated at this point, but at least I still have my Impala to drive. Even though it needs some transmission work and struts and has no heat.
ANY THOUGHTS????
 
Sorry, I stopped at engine light was on when I got it. Too far away to diagnose and helped. Could be a filter or vacuum line pinched along frame to tank. Not a consistent problem, I would leave at shop and have them drive it home until light stays out and problems are gone.
 
ummm... is there ~possibly~ an in-tank "lift pump" in that thing BEFORE the main fuel pump? My mind went straight to that after the description of the second stalling instance.

Not familiar with any of the GM fuel systems, so beat me up if the main pump is one and the same. :smirk:

Larry is right, though. The service manager or one of the techs should drive it until they get to the bottom of the issue.
 
Fix the heater in the Impala.
 
There may be a hose that goes from the charcoal canister up to the intake. If that has a leak, it might cause the codes and problems you're having.
 
I wonder if the evap vent solenoid is stuck shut (Different from the purge solenoid), or the vent tube is blocked. Then what is happening is that the tank goes into a vacuum because it cannot draw in fresh air. eventually the fuel pump cannot over come that, and the engine stalls.
How is it to fill the tank with fuel? Does the pump kick off a lot? that could be another symptom.
The problem didn't show up with the bad fuel cap because the air was leaking past it. now that you have a good cap its a problem. I'd try leaving the cap loose and see if it runs ok. It will give you the gross leak code, but the other problems should go away.
Something as simple as a spider web, or a mud wasp nest in the vent tube off the charcoal canister can cause things like that.
 
Mud wasps. I could write an essay.
 
Has any known service been done? If over 60,000 miles, O2 sensors can throw an EVAP code. Been there. Not easy to separate if using a low cost reader.
 
Only thing I could offer is, only buy trucks older than 93 and cars older than 73! Easy to fix, parts can be had at Pep Boys, etc and best of all you can work on them with normal hand tools and $25,000.00 diagnostic machines are not needed! :devilgrin:PJ
 
Problem seems to have been solved. Picked it back up this morning and drove it gently with no problems. After 20 miles of gentle, I switched over to a far more aggressive driving style. Engine ran smooth, I had lots of power, and the fuel mileage went up( it would fluctuate between 35 and 23 mpg with no real rhyme or reason.). Called the shop to ask what the did to it.....> Mass airflow sensor.... Didn't throw a code but it seems to have been the culprit.

Thanks guys!
 
Glad you're good again! Lots of sensors cover the evap and really sometimes has to be investigated thoroughly.
 
sd80mac7204 said:
Problem seems to have been solved. Picked it back up this morning and drove it gently with no problems. After 20 miles of gentle, I switched over to a far more aggressive driving style. Engine ran smooth, I had lots of power, and the fuel mileage went up( it would fluctuate between 35 and 23 mpg with no real rhyme or reason.). Called the shop to ask what the did to it.....> Mass airflow sensor.... Didn't throw a code but it seems to have been the culprit.

Thanks guys!
Click to expand...

Our 2005 Jeep doesn't one of those, does it?
 
If it is fuel injected, yes!
 
Dealership was a little frustrated with me. I left my Impala sit right in front of their showroom when I picked up the G6. When they called to ask why it was there I told them it was there so I had a ride home when the Pontiac quit again. That poor Impala is getting a lot of miles for being "retired". Loaned it out to a friend this morning whose Explorer did the usual Explorer thing and became an Exploder. Haven't decided if I'm going to mount the winter tires on that car or not this year.
 
PAUL161 said:
Our 2005 Jeep doesn't one of those, does it?
Click to expand...
A fuel injected engine needs to meter the incoming air to know how to adjust the fuel trim. The two most common sensors used for this are the Mass Air Flow (or MAF) sensor or the Manifold Absolute Pressure (or MAP) sensor. You can have either, or sometimes both of these. Without knowing exactly what 2005 jeep, with witch engine you have, a quick check on a parts store website showed Jeeps commonly using MAP sensors.
A MAF sensor sticks into the hose between the air cleaner and the throttle body and calculates the air charge amount by how much electrical current it takes to maintain a certain temperature on the sensor bulb as the air blows past it and cools it off. If a fault occurs, or enough dirt accumulates on the bulb, it can insulate the sensor and it begins to give false , low, readings. The computer sees less air coming into the engine and dials back how much fuel to add to the mix. Of course in reality there is more air in the mix, and the Oxygen sensors read this as a lean condition, and bingo! Check engine light!
A MAP sensor reads the amount of vacuum in the intake manifold and can use that reading along with the Throttle Position Sensor, and the RPM of the engine from the Crank Position Sensor to calculate the amount of air charge entering the cylinders.
With either of these setups any vacuum leak will alter the reading of the sensor and cause a lean condition due to what is called "un-metered air".
 
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