I have an ‘89 IDI SuperDuty and after sitting over a day or longer its hard starting. My question is isn’t there a check valve in the fuel line somewhere? Glow plug circuit is working as it should, it just seems like the fuel system needs to be primed.

Thanks.

 

there are several Check valves in the system......

return line in tank has Duck Bill check valves the shower heads have Check Valves, and the Mechanical fuel pump has 2 check valves.

on newer 7.3 IDI there is a check valve on the filter head going to the return line.. IF you don't have the Check Valve then you only have a Bleed Orifice on the filter head.

 

The filter head does have the Schrader valve bleeder.

 

yep they all had the Schrader Valve Test port... which is commonly used to Bleed the filter.

the check Valve or Bleed Orfice is screwed into the filter head and has a rubber fuel line connected to it that goes to the Fuel Return, normally connected to one of the Injector return Cups or to a "T" fitting between the injector return Cups.......... unless of course IF someone has plugged that return Port off on the filter head.



In Fact you can replace that return line from the Return Check Valve/Bleed Orifice with a Clear PVC line to check for air in Fuel.

 

Thanks for the advice, we bought the truck new so nothing has been removed or plugged.

 

Good deal.. but you know, we never know on many of them as they are old and often been thru many backyard mechanics so I had to mention that tid bit.....

Leaking injector return cup "O" rings seem to be common for causing air intrusion and Bleed Back... also seals on the injection pump can cause it or the olive seals in the supply fuel lines...

Anyway, here is Ford's Procedure .....