Fuel problem. Car stalls, chokes, and dies at startup
Posted June 20, 2007 at 04:35 pm
1. First time a few weeks ago: I went to start my car in the morning. It would crank over and start for a few seconds, and then immediately die. I tried pushing the gas pedal, and it would run for a few seconds, and die. I then starting pumping, starting, and floored the gas pedal almost to the floor. I revved the engine up high and it ran. A huge plume of black soot (carbon?) blew out of the tailpipe onto the street. The black spot is still there. After a few minutes, the car ran normally and I drove off to school. It ran perfectly the next two weeks, with the occasional stumbling at idle on first startup like it was still starving for gas intermittently.
2. Today: Car stalled from fuel issue on both startups today. It was below a quarter tank down to almost empty. This morning, it did the same thing as in the first scenario, but not nearly as bad. It did die when I first tried to start it. I revved the engine high, but not as long or extreme as the first scenario. Little or no black soot came out that I could see. Car ran normally and got me to school. I did not have time to fill it up. When I came out of school to drive to work, I tried to start it. It repeated the same thing again as this morning. I revved it and it stayed running. No black soot that I could see. I listened to the exhaust, and I heard what sounded like a backfire or audible pop like air being compressed and forced out of a tube. I have not heard that before. It sounded like I was forcing air and power out of the exhaust through a blockage. I filled the car with gas and it started normally. I went on my merry way. At least this car is still dependable once you start it.
3. What has been done to the car: EVERYTHING! New fuel pump, new fuel filter, major tune-up. Gets decent but not great gas mileage between 20-24 mpg. IMPORTANT: When my fuel pump failed, I used twice a very powerful German fuel injector and tank cleaner and ran the car three times on 91 Octane due to the advice of someone. I then switched back to 87 Octane. I also use nothing but Chevron now with Techron that is suppossed to be a fuel cleaner. I have ALSO had a bad habit lately of running the car down to 3-4 out 14 gallons left. I accidentally ran it down to 2 gallons once. Could my $450 dollar fuel pump already be having a problem. I hope not! How did you get rid of all that bad carbon that has been in my fuel tank since 1989. Any advice?
Any advice about carbon buildup and what to look for would be greatly appreciated.
Posted June 20, 2007 at 06:56 pm
Posted June 20, 2007 at 07:48 pm
Black soot indicates a rich condition. Check for codes.
Posted June 20, 2007 at 08:18 pm
I'm betting as a first pass, MAP sensor. That's how they act when they fail. It cannot be an O2 sensor on cold start.
Posted June 21, 2007 at 12:43 am
Posted June 21, 2007 at 12:49 am
Posted June 21, 2007 at 07:40 am
Code 31 Bad evaporator purge solenoid circuit or driver.
I have also been ignoring my computer codes 31 and 37 as I am told they are not serious
The evap purge DOES affect your mixture, perhaps not as much as the MAP sensor. But it tries to feed accumulated gasoline vapors from the canister back into the mixture. If it isn't getting those vapors, or if the purge driver is intermittent, the computer might be going crazy trying to compensate by changing the mixture and running it too rich. I'd check the whole evap setup, hoses, canister, electrical plugs. That code is there for a reason.
And no, carbon cannot build up in the gas tank. There is no combustion going on there. When gasoline evaporates, it can leave a gummy film, but that is not strictly carbon. And if the vapor pressure gets too high in the tank, the rollover valve vents it into the vapor canister.
Posted June 21, 2007 at 08:01 am
i would have to say that is low
20-24 mpg might be a little low, but it still falls near the EPA standards for that car. All my EEK's averaged 24-25 mpg in combined driving.
Posted June 21, 2007 at 09:44 am
Posted June 21, 2007 at 07:31 pm
Posted June 22, 2007 at 03:52 am
Posted June 22, 2007 at 08:05 am