After I get gas the car won't start without maintaining the throttle... why?

[Surge709]

So, weird issue.

After I get gas (every time I get gas, never when I don't get gas), the car won't start without me blipping the throttle and then gassing it to hold RPM for ~15 seconds. When I haven't just gotten gas, it starts up like new, every time.

What could be causing this?

[EthanolTurbo]

I had a similar issue recently, car would have trouble holding idle and would act funky when getting gas. It's most likely the sucking jet pump/transfer tube that moves gas from side to side in the tank... if this is clogged/loose or the returns are clogged, you will have funky issues with fuelling.

[Obioban]

I had a similar issue recently, car would have trouble holding idle and would act funky when getting gas. It's most likely the sucking jet pump/transfer tube that moves gas from side to side in the tank... if this is clogged/loose or the returns are clogged, you will have funky issues with fuelling.

I'm not sure that makes sense for something that occurs only after getting gas. Did yours occur in that specific circumstance, and not otherwise?

Feel like something EVAP related to me, though I don't know enough about how the system works to point to anything specific.

[sapote]

So, weird issue.

After I get gas (every time I get gas, never when I don't get gas), the car won't start without me blipping the throttle and then gassing it to hold RPM for ~15 seconds. When I haven't just gotten gas, it starts up like new, every time.

What could be causing this?

How long did you spend time at the pump - 5 minutes? Then just simulate it by shut off the engine at about same engine operating temp condition and wait for 5 minutes, and start it again to see any difference.

Pumping gas might force gasoline vapor into the intake manifold if the vapor solenoid valve is compromised, and this could cause a rich condition for starting up.

[COVID-19]

I had a similar problem with a Jeep and problem was something with the evap system and gas tank.

[EthanolTurbo]

I'm not sure that makes sense for something that occurs only after getting gas. Did yours occur in that specific circumstance, and not otherwise?

Feel like something EVAP related to me, though I don't know enough about how the system works to point to anything specific.

After I got gas the issue would flare up more consistently. It probably is evap though.

[Surge709]

How long did you spend time at the pump - 5 minutes? Then just simulate it by shut off the engine at about same engine operating temp condition and wait for 5 minutes, and start it again to see any difference.

Pumping gas might force gasoline vapor into the intake manifold if the vapor solenoid valve is compromised, and this could cause a rich condition for starting up.

I tried this last night. Drove the car for a bit, turn it off for 5 mins, fired it up-- 100% fine, not like after getting gas.

[bigjae46]

I'm with Sapote...probably an EVAP related issue. There is a vacuum line that runs from back to front, connects to the solenoid under the intake manifold and then goes to the Idle Air Valve.

IIRC, at start up, the throttle opens and then transitions to idle which goes through the intake, into the idle air valve to the air rail and is fed behind the throttle body butterflies into the cylinder. If the solenoid is stuck open then you should have a lean code.

As you refuel the car, you displace air through the EVAP system. Might have a problem with the charcoal canister? Might be clogged and forcing excessively rich air back through the vacuum line into the idle air tract. So the AFR is rich at start up. So you have the step on the throttle to open the TB butterflies to get more air in.

That's my guess...