2002 Dodge Ram 4.7 - Long cranking time to start?

[311Hemi]

Anyone have any thought on what to look for on a 02' Ram with the 4.7 that is having trouble starting?

Plugs/wire did not resolve the issue. Truck runs good once started. No codes are being thrown. It has been doing this off and on for a while, but might be doing it more often now. Only things that come to mind would be fuel pump or coils? This is my bro's truck and I have not had the chance to look at or work on this engine. Thought I would throw it out there to see if anyone has any ideas.

[Jeremy airjer W]

First thing I would check is fuel pressure. If it drops like a rock, which I suspect, you will be replacing the fuel pump module assembly.

[Lund79]

I have an '01 with 4.7 and had the same problem you described. Airjer is spot on for the fix that was done on my truck.

[Macgyver55]

Just did a 5.9 with the same symptom, fuel pump was the culprit.

[reinhard1]

same symptoms i had with my dodge ram . $600 to put in a fuel pump. two days later a young man i take fishing at times said he would of done it for $300. i said i will call you first next time for any repair. good luck.

[The Grebe]

I used to do that...but a couple of times it didn't turn out so ggod and there was nobodys feet to hold to the fire! You might save a few bucks and lose a fishing partner.

At the garage, if it isn't dome right, it's a do over. It comes with a guarentee and you shouldn't have to worry about it. Only exception is if the person doing the cut rate mechanical fix is a real mechanic with all the tool and know how, doing it on the side....then it could be a sweet deal....especially if he can get you in and out with out waiting very long.

[reinhard1]

yea, i hear you and i have always take my vehicles to a repair shop i trust. this kid has done brakes for me and other stuff. i kind of adopted him after his dad went to prison when he was 14. he's 32 now with a family and needs the money and i need the savings. he told me he has done this before. major things i will take to the repair shop [hopefully not needed]. good luck.

[311Hemi]

For those of you that had this issue, did your truck run fine once started (before being fixed)?

My bro said he had a mechanic check the fuel pressure when this was happening and the fuel pressure looked good, but I was not there to see exactly what they did. I was wondering if it could be one of the back flow valves not working properly and the line draining back towards the tank.

I don't own a fuel pressure gauge, is that something relatively cheap to purchase for testing this? Also, can anyone tell me where the port is to hook the gauge up to?

[Jeremy airjer W]

For those of you that had this issue, did your truck run fine once started (before being fixed)?

[reinhard1]

in my situation before the truck totaly did not start, i would turn the key and let the engine crank a little, shut it off, and turn the key again and it would start right away. well that worked for awhile but one day the engine would just turn over but not start. good luck.

[solbes]

Fuel pump went out on my '02 4.7 Dakota two years ago (90,xxx miles). I had it into the dealer to fix a window motor that had broken due to freezing rain. Also wanted them to look into why it was taking longer to start after the truck had sat for more than 4 hours. Fuel pump was the issue. After replacement it starts like it always had, great!

I seem to remember that if I let it prime (key in "on" position for 3-4 seconds before advancing to "start" position, it would take less time to start. Just another indication that the pump was failing.

[Lund79]

Before I got it fixed, once it would start it ran fine. Before I got it fixed, I noticed it took longer than usual to start. Maybe an extra 2 seconds or so.

[311Hemi]

I talked to my bro again and he said the fuel pressure was ready at 50 the whole time they were checking it, including during the long cranking. He also told me today that he has been smelling gas when starting. Could it be a faulty fuel pressure regulator delivering too much fuel at start?

[Scott K]

The spec is 50, so that would be ok, the question is, when you turn the key off, does it stay at 50?

[rng]

Find the fuel pres. regulator on the fuel rail, pull off the vacum hose, if gas drips out of vacum hose and regulator you have a bad diaphram and you need to replace the regulator. A bad regulator can give the same hard start as a bad fuel pump.This is a easy check and would explain the gas your brother smelled.

[Jeremy airjer W]

There is no fuel pressure regulator on the fuel rail under the hood.

Dodge puts the regulator in the fuel pump and runs a single pressure line to the fuel pressure rail. There is no return line from the fule rail back to the fuel tank so there is no need for a fuel pressure regulator on the fuel rail. The pump is already sending the appropriate fuel pressure right from the fuel tank.

[311Hemi]

I am not sure if the pressure dropped off when the truck was turned off. I will be seeing my bro tomorrow and will hopefully find out more.

Below is what I found in my 03' service manual. From the sounds of it if the fuel pressure regulator was delivering too high of pressure any extra fuel should be routed to the tank by way of an internal diaphragm. I wonder if the diaphragm was bad could that deliver to much fuel pressure to the rail?

Either way it sounds like we will need to access the tank. Anyone think it's easier to lift the bed vs lowering the tank? I have read that unbolting the bed can be easier.

Quote:

Fuel Pressure Regulator Operation: The pressure

regulator is a mechanical device that is not controlled

by engine vacuum or the Powertrain Control

Module (PCM).

The regulator is calibrated to maintain fuel system

operating pressure of approximately 339 kPa ± 34

kPa (49.2 psi ± 5 psi) at the fuel injectors. It contains

a diaphragm, calibrated springs and a fuel return

valve. The internal fuel filter (Fig. 2) is also part of

the assembly.

Fuel is supplied to the filter/regulator by the electric

fuel pump through an opening tube at the bottom

of filter/regulator (Fig. 2).

The regulator acts as a check valve to maintain

some fuel pressure when the engine is not operating.

This will help to start the engine. A second check

valve is located at the outlet end of the electric fuel pump. Refer to Fuel Pump - Description and

Operation for more information.

If fuel pressure at the pressure regulator exceeds

approximately 49.2 psi, an internal diaphragm opens

and excess fuel pressure is routed back into the tank

through the bottom of pressure regulator.

Both fuel filters (at bottom of fuel pump module

and within fuel pressure regulator) are designed for

extended service. They do not require normal scheduled

maintenance. Filters should only be replaced if

a diagnostic procedure indicates to do so.

Quote:

Check Valve Operation: The bottom section of

the fuel pump module contains a one-way check

valve to prevent fuel flow back into the tank and to

maintain fuel supply line pressure (engine warm)

when pump is not operational. It is also used to keep

the fuel supply line full of gasoline when pump is not

operational. After the vehicle has cooled down, fuel

pressure may drop to 0 psi (cold fluid contracts), but

liquid gasoline will remain in fuel supply line

between the check valve and fuel injectors. Fuel

pressure that has dropped to 0 psi on a cooled

down vehicle (engine off) is a normal condition.

The electric fuel pump is not a separate, serviceable

component.

[Jeremy airjer W]

I have never had a dodge with to much pressure. Fords on the other hand......