2008 Explorer 4.0 long crank condition

[relentless85]

Started to get a long crank condition when trying to start my 2008 Explorer 4.0 SOHC. Was experiencing long cranks after the engine sat for a few hours or overnight. Now the extended crank is becoming more frequent. So far, no check engine lights and engine runs smooth after start up. Last week I replaced the spark plugs, plug wires , fuel filter and air filter. It was due for a tune up anyways at almost 120K miles. Plugs are Autolite platinum and gapped correctly. Wires are Motorcraft and the fuel filter is Motorcraft.

I have read that a possible cause of the extended crank could be injector failure. I did notice before I replaced the plugs and wires that it smelled rich.

I plan on using an OHM meter to check the injectors individually. What should the OHM's be for the injectors on the 08 4.0L SOHC?

What should the fuel pressure be when the engine is not running and after start up while running.

Would a coolant temp sensor cause this symptom? If so, how can I check the coolant temp sensor.

Any where else I should be looking?

Thanks!

 

[94Eddie]

Try cycling the key to the on position 2-3 times before cranking it. If this solves the problem then you likely have a fuel pump issue. This would indicate that over time the fuel pressure is dropping and the pump takes time to achieve the required line pressure so the engine will start. A leaking injector could cause this but the engine should run rough from a cyclinder being flooded right after starting. If it runs smooth then it might be the check valve in the fuel pump is leaking and mot holding pressure in the fuel lines.

 

[J_C]

AFAIK fuel pressure should be around 60-65 PSI. Do you have loss of power under heavy acceleration? Coolant temp sensor reading can be seen with a scan tool capable of live data, and you might also see misfires shown.

I don't know the injector ohm values but they wouldn't all suddenly fail simultaneously so you could measure them all and see if one reading is off compared to the others, though I agree with 94Eddie that it's probably not the issue since it runs okay once started, but it would be inexpensive to just put a double dose of fuel injector cleaner in the tank per amount of fuel in it and run that a while, or if it's very old gas, put some fresh in.

Just for the heck of it, I'd check battery resting voltage (after hours sitting off) and while cranking, and examine battery cable clamps for tightness and corrosion.

 

[Justin J]

If it happens at warm start (hot, then off for 20 minutes or so), but not happen at cold start, try depressing gas pedal slightly when igniting!

My ford has this issue and all my research points to leaky fuel injectors, which floods cylinder at warm start! It won’t be an isssue in cold start as the leaked fuel would have evaporated by then.