2008 Kia Rondo, V6
Starts in an instant EXCEPT when at gas station for a fill up. Takes over 30 seconds of cranking, stalls 2-3 times and runs crappy for about one minute.
Is the gas cap part of the computer system?
Thanks for advice.
It sure does. It sounds like it's venting the charcoal canister and fuel
tank way before it should. Need to have a look at what the canister/tank
purge system consists of and then go from there. Check too that the
canister hasn't been fuel soaked - that kills them pretty quick.
Your system should be similar. Check out the purge control solenoid
valve. They tend to stick open and flood the system. You could try full
throttle (clear flood mode - reduced fuel delivery at injectors) when
starting and if it starts a shade more easily, then the purge control
solenoid valve or its upstream circuit should be looked at.
Bad purge solenoid. It is in the engine compartment near the intake
manifold and allows the engine to draw off the collected vapors from the
charcoal canister. When they stick open the action of filling the gas
tank drives the vapor up into the intake manifold and you end up with
such a rich mixture that the engine won't start. Very common failure and
In rec.autos.tech, on 29 May 2018 09:50:24 -0400, firstname.lastname@example.org
I saw on a TV court case where a shop told a Volvo owner that his loose
gas cap had cause his something something pump to run all the time and
that caused it to burn out and set the check engine light.
By the time I got to the conputer, I forgot what the first two words
Do you or does anyone here know the things full name?
Does this sound believable. He said the pump was meant to increase or
maybe equalize air pressure in the gas tank.
A leaky gas cap causing an electric motor to burn out? Sounds like a bunch
of hogwash to me.
I was working on my daughter's Jeep Cherokee today in the hot tropical sun
and the thought occurred to me that it will be a great day when cars are el
ectric and I won't have to look for vacuum leaks and replace emission contr
ol sensors/valves. All this will be over like some bad dream.
Leak Detection Pump.
It's Part of the EVAP (aka Evaporative Emission Control System), and
tests the fuel tank to make sure it can maintain pressure and vacuum at
certain levels, which means fuel vapor (fumes) won't escape.
It's not a typical spinning-electric-motor type of pump, but a set of
solenoids, diaphragms, valves, and orifices that are activated by the
ECU. Close the external air vent, open some vacuum ports, and measure
how fast the tank gets sucked down to a set level. Open/close other
valves, then pulse the diaphragms to slowly pressurize the tank, and
measure that. If the readings don't change fast enough, or stay steady
long enough, the system assumes there's a leak, and the Check Engine
light will turn on. Cars are usually only tested once per "warm-up
cycle", and only for a few minutes, so all leaving the gas cap loose
does is set the light, not "burn out" the not-really-a-pump.
That concludes today's lesson. Class dismissed. :)
Note that when this system is cycling, you can hear it going ka-thump,
ka-thump in back. It should be one of the things that you listen for
when the car is starting up. If you can hear it going on continuously
all the time it should be pretty clear something is not right.