07 LMM harder to start

[thrilskr]

First, please excuse my 'newness'. Iv'e been searching for an answer in the forum but to no avail so hopefully someone can assist. Thanks
I have an 07 3/4T GMC Sierra crew w/ the LMM. 30,000 miles now. It has always started immediately but recently, it now takes about 3 seconds of cranking before it starts. It might not seem like a big deal but it has me concerned. It didn't do it sporatically, just started a week ago and has not changed a bit. It was at a half tank of gas when it started and I filled it up yesterday and it still does it. Doesn't appear to run any differently once it's started.
Any help or insight would be appreciated.
Dan

[DmaxMaverick]

Welcome aboard!

How many miles on the fuel filter? It should be changed at 10-15K miles. Many starting issues can be attributed to overdue filter changes.

[thrilskr]

Thank you. Actually, dealership replaced 2-3 hundred miles ago. I inspected the engine compartment and I found a small fuel leak. Can't see exactly where but it appears to be from a small plastic fitting on the underside of a white cannister(I think it's the fuel filter) on the passenger side of the engine. Looks to me like a hose should be connected to it or its a type of runoff or overflow. There is fuel on the frame beneath it thats running down the suspension to the floor. It's not very much. I'm not familiar with diesels yet, but pretty savvy with small block chevys. Thanks for any input.
Dan

[DmaxMaverick]

That plastic thing at the bottom of the filter is the WIF (Water In Fuel) sensor and water drain. It's not supposed to have a hose attached (although you can install one). If it's leaking, it can surely cause hard starts. Once the engine is running, the fuel system is under negative pressure, as the HP fuel pump draws fuel from the tank (no lift pump). An external fuel leak with engine off will mean an air leak with engine running.

Check the sensor. It should have an O-ring sealing it to the filter element, and the water drain valve also has an O-ring. If they are loose, that's a no brainer. Tighten them. If not loose, remove the sensor (be sure to disconnect the harness connector first), check the O-rings, lube them, and reinstall. Be careful with the sensor. It is plastic, afterall. I use water pump pliers (carefully), but a wrench is available for just this purpose.

It's probably better to return to the dealer who did the service and have them do it for you, being their fault in the first place.