Chevy Caprice does not start after driving in summer

[Kooolman]

I have chevorlet caprice 2006 LTZ, whenever I switch off my car after running with AC on (means heat shows 50%) does not start. It simply cranks up but does not start,I try 3-4 times it starts, everything works fine . It starts perfectly in morning or after idle for long time. What stops the start, is it the fuel pump? I did computer scan but nothing detected.
Please I am clueless and need help!

Thanks

Shahid

[silicon212]

Fuel filter, perhaps. Could also be a weak fuel pump. If you can get a pressure gauge, hook it to the fuel rail diagnostic port and see what the pressure is. It should usually range about 50PSI +/- 15PSI.

[Blue Bowtie]

Fuel bleed-off is also a possibility. This can be through injectors or a pressure regulator, although the regulator in an '06 may be in the tank, making that less of a possibility. If the leakage is through the injectors, the accumulated fuel will flood the engine. After several hours of sitting, the excess fuel tends to evaporate, allowing a normal start.

As the SandMan indicated, a pressure gauge will be very helpful. Not only should the standing fuel pressure be checked, but after the pump is off monitor the residual pressure to see how quickly it drops.

Another thing that may help starting after heat-soak is to invoke the Clear-Flood Mode by holding the accelerator to the floor while cranking. Be ready to release it IMMEDIATELY as soon as the engine starts. Opening the throttle past 80% not only admits more air to dilute any accumulated fuel, but also cuts off injector pulses while cranking to prevent further flooding.

[j cAT]

Originally Posted by Kooolman

I have chevorlet caprice 2006 LTZ, whenever I switch off my car after running with AC on (means heat shows 50%) does not start. It simply cranks up but does not start,I try 3-4 times it starts, everything works fine . It starts perfectly in morning or after idle for long time. What stops the start, is it the fuel pump? I did computer scan but nothing detected.
Please I am clueless and need help!

Thanks

Shahid

what engine you have in this caprice LTZ ? V6 OR the 6 LITER V8 ?

these are not available here in the US...

if you get the engine to start when hot , with the throttle pedal down , then you may have fuel problems like bad/dirty injectors.

make sure the radiator is clean / wash the radiator anyway..

http://www.drivearabia.com/ultimatec.../2005-2006-/12

[Kooolman]

Thanks guys for your support. It's v6 ltz and its does not have option to check fuel presure guard. I took it to mechanic and he also could not find any problem. When it's cool down it starts perfectly.

[Kooolman]

Today I took car to mechanic and he did computer scan and displayed following error"Fuel pump Relay Ciruit Malfunction"

Any clue what does it mean of above error?

[j cAT]

Originally Posted by Kooolman

Today I took car to mechanic and he did computer scan and displayed following error"Fuel pump Relay Ciruit Malfunction"

Any clue what does it mean of above error?

with hot temps these relays can fail because they get too hot. this could be the problem. have the relay replaced but keep it. if it seems to work for a few days put the old relay back in just to be sure it is the relay not just a bad fit in the relay socket/connector. GM had problems with relays controlling the cooling fans and this causes engines to overheat. it is called coil saturation when the coil heats up too much/draws too much current. good luck ..