I started having problems with my '99 Cirrus last month, it would randomly stall while driving or while in idle. With no check engine light or any other tell tale signs of a problem. I’m not entirely knowledgable about how the entirety of the car’s systems function, though I new I should check my fuel system. I wasn’t getting any fuel to the engine whatsoever, so I replaced the fuel filter because when I got it off and looked at it it was clear it was bad. Then I put it all back together to try and run it and it continued to stall. Thinking it must be the fuel pump at this point I dropped the fuel tank and replaced it. It ran for about 35 miles before the same problem started happening again. So I checked all the fuses, and relays and just to be safe replaced all the relays related to the fuel pump, and fuel system and i even replaced the auto shutdown relay. The car continued to have the same problem, so I did some research and found out it could be a dirty throttle body so I cleaned it even though it wasn’t that dirty, and checked my air filter for how clean it was and it was clean. The car still continues to stall in idle and while driving. I’m out of ideas for what could possibly be wrong, any help would be much appreciated.
Take off the gas cap and drive around. Tell us if the stalling problem goes away. Also, which engine does your car have?
It has the 2.5 L V-6 engine.
I took the gas cap off and drove around, it got rid of the rough idle and was idling a lot more smoothly, and it didn’t stutter or anything while driving. Though I thought driving without the gas cap on resulted in a check engine light and mine never came on.
Do you by any chance “top off” the tank after the pump clicks off at the gas station? If so, you’ve soaked your evap charcoal canister and the tank can’t vent properly as a result. Don’t top off - the first click means it’s full.
What’s happening is that as fuel leaves the tank a vacuum is created. Air needs to be able to get into the tank in order to mitigate that vacuum, otherwise the fuel pump is trying to pump fuel while the vacuum is trying to suck it back into the tank. Eventually, you get to the point where the vacuum is sucking harder than the pump, and that’s when your engine starts to sputter.
If you don’t top the tank off then it’s probably more likely to be the evap canister purge valve. When it doesn’t function properly, the same problem can happen - the tank doesn’t vent and the pump gets overpowered by the vacuum.
But shouldn’t that still come up with a computer code? I hooked it up to my computer reader and it had zero codes come up.
Not necessarily. The relevant code would be P1486, “evap leak monitor pinched hose” which can be thrown by a blocked canister. Depending on how the system is set up, it might not trip before you noticed problems. It’s also possible that the sensor which should be tripping the code is malfunctioning.
At any rate, taking off the gas cap cured the symptoms, which tells us that introducing a vent to the fuel tank fixes the problem, which tells us that the vent system isn’t doing its job.
Good call @shadowfax, it looks like you got it on the first try! That wouldn’t have been my first guess.
For the OP, here’s a link which explains how the Chrysler evap system works.