po446

[qukon 95]

anyone fixed this code? 99 tahoe truck starts ok at times then sometime it will take 10 to 20 mins for it to start. no problem with the cranking.

 

[east302]

You'll need a good scanner to command various functions in the EVAP system to diagnose the code. If you have access to one, I'll post the diagnostics.

I kind of doubt that it'd cause driveability issues, though.

What are your hard-start symptoms?

 

[qukon 95]

don't have this advance scan tool. also what is the sensor mounted on top of the gas tank in the rear. sometimes her truck starts right up and some times it won't start for 15 min like it's out of gas, pump been changed thinking that was the problem,i took canister off blew air though it the air comes out of the ports really good .i need to find wiring diagram to check voltage out put from pcm.
i did get the purge valve out of junkyard still this code still coming on.

 

[east302]

For the no-start, I'd do a pressure test. Key on, engine off, the fuel pressure spec is 60-66 psi and should hold in that neighborhood for a few minutes after turning off the ignition.

If the fuel pressure is good, it may be worth looking at the engine coolant temperature sensor which is right by the thermostat. Sometimes, when they get flaky, they'll cause hard hot-starts. You'd need a scanner to see what temperature it is reporting. When it happens again, hold the gas to the floor and crank it. This is the "clear flood" mode and temporarily pauses the injectors. If that works, I'd suspect that temperature sensor.

 

[qukon 95]

do you what that sensor is called on top rear of the gas tank