2006 Avalanche

[Anson 0]

2006 Avalanche w/6.2 Black Scorpion. For whatever reason after running and then shutting down for more than 30mins, it will not start. It seems like a vapor lock.  Runs good with no hesitation at all when running.  I installed a new booster pump, water separated filter and fuel filter, but it still does it.  I  managed to get it started by using full throttle a few time. I’ve also had to be towed in a few times and have start without any problem in a few hours.  After looking online, it seems to be a common problem, but I haven’t found a fix.  If anyone has any idea, please help. Also, where is the fuel cooler installed on this thing and is it even possible to get to it without removing the entire engine.

[InfinitySurf 302]

Sounds like you are on the right track with the vapor lock.

Maybe try keeping the engine compartment open.....as well as run with the blower on to keep removing the heat from the engine bay. If nothing else this will verify for sure that vapor lock is your issue.

Have head that you can install a fuel cooler check valve that may help.

Found this too:

Pour cold water over the fuel pump and fuel lines while the ignition is in the off position. This will quickly cool down the fuel pump and condense the fuel from vapor back to liquid form, eliminating the vapor lock in the fuel pump and lines.

 

• If you are routinely having problems with vapor lock in your vehicle, wrap the fuel lines leading to and from the fuel pump with aluminum foil. This will help insulate the lines and prevent the fuel from heating up to the point of vaporization.

Here is a link to a pretty detailed write up on vapor lock:

https://www.perfprotech.com/blog/articles/mercruiser-vapor-lock

[rhino89523 34]

Don't have much to add, but I love old Internationals and they are the king of vapor locking. Insulating the fuel lines in the engine compartment fixes it on IH's. the make some pretty cool sleeves and they make some stuff kind of like aluminum foil with some good sticky stuff to hold it together all sold at Summit Racing.