First a little background...
2001 Dakota quad cab, 4.7L V8, auto.

Had hard start issues last winter, but just on the really cold days. The colder it was the harder to start, but this summer started out fine. Lately it's been getting worse and worse. Now it takes like 20 cranks to get going.

It was throwing codes P0442 and P0455 last winter (small EVAP leak and large EVAP leak). I found a huge hole in the vac line coming out of the throttle body and replaced that and cleared out the codes. There was definitely a leak there but fixing it didn't effect my hard start and those 2 codes came back along with a P0302 (misfire in cylinder 2).

I rented a fuel pressure gauge and found that my fuel pressure is dropping to 0 within about 10 sconds of shutting the engine off. I get 45 psi once it's running (or even just cycling the key), and it runs great once it gets started.

I hate to just throw parts at it. Im guessing that the leak down is occurring on the tank side. Is the check valve replacible or do I have to replace the whole fuel pump assembly on these? A bad injector wouldn't cause it to leak down to 0 psi in 10 seconds would it?

Any suggestions on where to look?

I'm assuming it's supposed to hold pressure after shutoff, or is this normal?

 

A bad injector CAN cause a hard start and CAN cause a leak down.

The check valve is part of the pump assembly. It's replaced as a unit. It can and will leak down after shutdown but it shouldn't drop immediately.

 

Thanks for the quick reply.

So is there a check valve in the fuel filter on these too?

 

The filter is also part of the pump assembly. It's a "lifetime" component.

 

Gotcha. Thanks.

Guess I know what I'll be doing one of these weekends...

 

Have had a rash of that at work lately been changing fuel pumps to solve problem there is a pressure regulator in the pump assembly that does go bad and causes the pressure to drop to zero as soon as truck is shut off. I f you attach pressure gauge turn key to run position fuel pressure should come up to 50-60 PSI then turn key off drops quickly to zero then I would swap pump assembly

 

Update:

I got a new pump assembly in from Rock Auto and swapped it out. Truck starts like brand new every time now.

As a side note, if you follow the instructions to remove the bed to access the fuel pump from above without dropping the tank those instructions are apparently for the single cab and extended cab trucks. If you pull the bed off of your quad cab truck you will only be able to see the fuel pump but not actually remove it because it sits 1/2 way under the cab.

 

The quad cab was kind of an afterthought of the dakota, I think.