VP 5.7GXi-E, Poor Hot Start

[phillyg]

My 2004 5.7 starts easily from cold and runs great. Occasionally it will stall as I come to a stop, after which it will crank but not re-start with the throttle in the idle position, unless i give it throttle. I've replaced the idle air control and no change. Anyone know what I need to look at next?

 

[alldodge]

Check vacuum
Looking at a scanner while running we could find out the position of the IAC. Could be vacuum is low and the IAC is almost full open to keep motor running.

 

[phillyg]

Check vacuum
Looking at a scanner while running we could find out the position of the IAC. Could be vacuum is low and the IAC is almost full open to keep motor running.

Unfortunately, none of the "experts" in my area have a scan tool for these motors. I will put a vacuum guage on it to see if there's any clues there.

 

[ripjmk]

I just cured my hot start issue by replacing the HP fuel Pump. In my case the pump discharge check valve was leaking allowing the rail pressure to decay to nothing. When cold this is not a problem as the fuel is liquid and pressure rises fast at pump start up. But when hot the fuel in the rail has turned to vapor and it takes a lot of cranking to get liquid back in the rail. A good test is to put a pressure test gauge on the rail turn the ignition on to prime the rail turn off ignition and see how quick the pressure decays. If the injectors and rail pressure regulator is good and the HP pump check valve is good the pressure should remain for 3-5 min at least. If it starts good from cold I think you can discount the injectors and rail pressure regulator leaving the HP fuel Pump (this assumes you have removed all paint from inside the fuel cell).