2000 cavalier 2.2 starting issue
 

Hello, so I've been driving a 2000 cavalier for a few months now and it's been a good little car so far but ever since I bought it it's had this issue where the engine starts rough when the engine is warm. Basically when you try to start it it turns over just fine but takes several seconds and often a little bit of pumping the gas to get her to stutter to life and after it running rough for about ten seconds it runs and drives just fine. In the morning when the engine is completely cold it starts up just fine and if you try starting it within say 10 mins of turning it off it will also normally start fine but any longer and it starts rough. I replaced the coolant temperature sensor thinking the engine might be thinking the engine is cold when it's not thus giving it to much fuel but that didn't help. I can definiley smell the fuel pretty strong once it finally starts. So I was wondering if anyone else has experienced this problem and what it could possibly be, any advice would be greatly appreciated.

Any chance you fixed this or found the problem?

I'm having the same issue and hoping anyone with any idea can chime in. Unfortunately these cars are dying and along with it the online help. :(

if you can smell fuel you need to be looking for a leak, the fuel pressure regulator is a common issue to start looking at, also unplug the vacuum like and see if any fuel comes out. If fuel comes out then the regulator is bad

No fuel smell or fuel in the vacuum line. The previous owner replaced the FPR so it is newer. I've checked most of the things I've seen around the forums and no fix as of yet. It's a weird issue that I didn't think would be this difficult to figure out. Cold (even -25 degrees!) starts like a charm, Hot (you just went into the store for 10 minutes) starts fine. Warm (you shut it down 20 minutes to 2 hours ago) 5-10 seconds of cranking or floor it and it will start fairly quick.

Exactly the same for me, still haven't figured it out. I already checked the FPR so I know it's not that. I'm thinking one or more of the cylinders is flooding with gas which is why it fires up easy when it's cold.

After conversing with a friend we were wondering the same thing. As if 10-20 minutes after shutdown an injector leaks enough into the cylinder to flood it? Or perhaps some sensor elsewhere was getting heat soaked after sitting?

We thought about just emptying or relieving the pressure in the fuel rail after a hot shut down to test the theory.

I wanted to hook up a fuel pressure gauge to see if it loses pressure after shut down but apparently the only way to do it is to splice into the fuel filter since there's no test port on the fuel rail.

an injector leak could be a possibility, it would cause that cylinder to misfire on startup for a short bit then clear up. Any codes? fuel pressure/volume been checked? Do you have access to a scantool at all?

No codes, checked it with a scan tool before. I'd like to check the fuel pressure but there's nowhere on the fuel rail to hook up a gauge. I thought it might have been a bad fuel pump check valve but if that was the case it wouldn't start so easy when cold. Almost has to be a flooding issue such as a leaky injector like you said, I honestly can't think of anything else.

When I find time I'm still poking at this issue so I'll raise it from the dead. Have you noticed with your issue that the problem occurs also when the temperature is warmer out? I'll drive it to work and try to start it 4-5 hours later and if it's 50 degrees out there isn't a problem but if it's sitting in the 70-80 degree sun the same issue seems to happen. Just a random thought and I suppose it still could be the whole leaky injector issue we were talking about.