No start after getting gas

[piley]

I need some help here - 99 Alero 3.4l V6.
The car starts fine and runs fine - except after I get gas. Every time I fill up, I cannot start the car. It starts then stalls right away - it won't idle. If I keep my foot on the gas to keep the revs up it's fine. I even have to keep my foot on the gas (and brake) to shift into drive to be able to leave the gas station. After a minute or so it will work normally. If I stop and shut the car off again it will start right up and idle normally. I only experience this after filling up at the gas station.
Any thoughts? It's driving me crazy.

Paul.

[JTrujillo86]

Wild guess -

My friend has a Cavalier which was doing the same type of thing. It was caused by bad injectors that were leaking into the cylinders, flooding the engine. His did it all the time though.

Try this: When you start your vehicle the next after you get gas, push the accelerator pedal all the way down. That's what the manual says to do if the engine is flooded. If this solves your problem, then I would definately say you have some bad injectors on your hands. Let us know what happens.

Jeremy

[DamienZ28]

Wow nows theres a mystery! It could be bad injectors for sure they also just might be clogged. Do you ever use fuel injector clearner? a bad spray pettern will cause problems like that also if they are dirty. Also if they are dirty they be just dripping excess fuel in the chambers causing a flood problem. You didnt mention how many miles you have on the car but im guessing 50,000 or more and that youll go to any gas station to get gas as long as its cheapest. The cheapest things to try first is use some injector cleaner test your fuel pressure and change the fuel filter. If none of that helps you can get your injectors flowed er cleaned and the spray pattern tested. Or you can replace them all with new ones but if there aftermarkets on the cheaper side then id have them tested before even installing them. Mabey some of that will help!

Good Luck!

If you do get it fixed will you post the answer here? THanks...

[piley]

DamienZ28 - thanks for the info.
The car has 60K miles on it and I haven't tried fuel injector cleaner. I did hook up a fuel pressure gage and the pressure is good (approx. 41 psi key on, engine off) and the pressure holds steady after the key is turned off so I don't think the injectors are leaking.
The funny thing is I can't figure out why this only happens after filling up at the gas station. It's the only time the car stalls like this.

When I figure it out I will post the solution.

[JustDrivingAround]

Sounds familiar!! Just took my 99 Alero in 2 weeks ago for the same reason...always after gas fill up the exact same thing happened to my car. They said that my computer needed updating in my car and it wasn't allowing enough gas to get through...service invoice says "reprogram pcm". That's all they accounted for it after doing a full diagnostic. Good luck!

[piley]

JustDrivingAround,

thanks for the info. Before I take the car in for this "magic" reprogramming - did it actually fix the problem?

Paul.

[JustDrivingAround]

Yes piley, since then the car runs smooth and all gas fill ups since have gone off without a glitch! (2 wks and counting) A good while after this started happening to me...my engine indicator light also went on, so I reported that at the same time too. All they did for that was replace the fuel cap due to the gasket not fitting tightly enough on the old one and did the computer updating and ta-da!

[piley]

Thanks JustDrivingAround.
My engine light also came on and I changed the gas cap (figured that was the problem) but never cleared the codes. I'll bring it in to the dealer for the reprogramming.

Thanks again,
Paul.

[JustDrivingAround]

Very welcome piley. Let me know how that works out for you.

[ugsrich]

Interesting problem you have. I suspect that it has something to do with the level of gasoline in the tank and possibly into the fill-pipe. The recirculation of the gasoline from the tank to the fuel rail and back is a continuous process fed by the the fuel pump which is submerged inside the fuel tank. If you are filling (and maybe even topping off) the tank there may be insufficient air in the tank to accommodate the pressure difference being created by the fuel pump. As you drive you may jostle the fuel enough to allow all the air trapped in the tank to move up the fill pipe and provide sufficient means for the pressure to equalize and allow for proper fuel system pressures to be created and maintained.

It sounds as if you always "fill" the car. So I presume that if you add only a couple gallons (no "fill") this would not occur(?). I too "fill" all my vehicles. Perhaps the gasoline nozzle shut-off is not triggered soon enough when you fill your Alero, or perhaps like me, you squeeze in a little more after the nozzle shuts off. In any event, I would do a little more experimentation before taking it in. See if you can identify a the fuel level at which this occurs. Or, if you fill it the same way as always, try shaking the vehicle from side-to-side to move any trapped air up into the fill-pipe. (pick a sturdy place on the body to push so you don't dent the quarter panel by pushing on it).

I’d like to know how this works out. Let us know if you do any additional experiments.

’95 Aurora, ’97 Regal, ’01 Alero V6 3.4

[piley]

Hi ugsrich,
That's a very interesting way to look at the problem. I haven't brought the car in yet so maybe I'll try this first. I always "fill" the car and top it off a bit after the nozzle shuts off.

I'm going to try a few other experiments as well and I will post the results. From what I gather there is a check valve in the fuel filler tube to keep the tank pressurized (part of the EVAP system). The only way to depressurize the tank is to remove the vacuum lines from the canister purge solenoid. What I am thinking is when I fill the tank, the check valve opens up and the tank depressurizes. When I start the car it stalls because there is no pressure in the tank - maybe this causes problems with the fuel pump.
If I keep the revs up the car will run and maybe the continuous fuel flow repressurizes the tank and the car runs normal. It has me baffled.

I had DTC P01441 show up and I replaced the gas cap and checked the vacuum lines. The code hasn't reappeared and I don't have the equipment required to do the EVAP testing for this trouble code.

Stay tuned............

[piley]

Quick update.
Turns out it was my fault!
When I changed the intake gaskets I must have reversed the vacuum lines at the canister purge solenoid - even though I checked them about 10 times<g>.
I couldn't find the problem and brought it to my dealer. It didn't take them long to point out my stupid mistake. Oh well, the car runs great now. Next time I'll be sure to label each line before I remove it!

[DamienZ28]

Well thats a bummer! Atleast everyone gave some good information! Never thought about it being a vacuum line.. Of course ive burned a hole in some pistons from that before on accident heh... Glad to see your car is better!