Thanks, MikeD. Good tip. I never thought of that pulling it down but it makes sense. (I haven't hooked the grid heater up on my engine...)

 

It cranks for a very short time . . . starts right up and idles fine. Runs good when cold. As it gets hot, it starts smoking and losing power!

 

If the CP3 was weak it probably wouldn't start well. Does it start well when hot too ?

Get a scanner on it and check out rail pressure, boost and engine load %.

This should be pretty easy to figure out.

The 3rd gens have a bad rap for being complicated. But once you understand how everything works together, they are pretty simple. All you need is a scanner and some patience.

I hope the Walbro works well for you. I'd still like that part number and pictures too when you get a chance. I'm getting a lot of Walbro requests and it would be great if you could help others wanting to install them.

 

Something is funny here or DC ripped you off with the "no power at the pump" scan.

I'm pretty sure your truck has a fuel pump relay. And the ECM just senses if the relay coil is taking current appropriately. Are you sure your pump relay is good ? As far as I know the ECM doesn't sense the pump electrical power at all.

If your ECM did give a "fuel pump relay error", then DC should have told you to change the relay.

I'm at a big dis advanage here because I don't have a Dodge truck to look at, nor an 04.5, nor an 04.5 shop manual.

But it sure seems like your Walbro has good electrical power and is making good pressure.

Wanna bet they saw the bypass, found the Walbro, remembered that 2nd gens with the VP44 powered the fuel pump directly and told you it wouldn't work without really checking things out ?

Something is funny here. Hmmm.... why does this happen when we get a dealer involved ?

 

MikeD is correct. Those grid heater elements draw some serious amperage. When I first installed my Walbro, my pressure was going from 12psi to 18psi and it was driving me nuts... Until I realized what was causing this.

 

What scanner will will actually work on the 04 CTD other than the DRB3? I'd like to access the rail fuel pressures and other info. All I have is a AutoXray 5000.

 

Once the truck starts grid heaters are not really needed. You could hook up an oil pressure switch and run the ground from the grid heaters through it. Once the engine fires and there is oil pressure the grids would be turned off.

That would solve the grid cycling problem.

 

Any scanner that works on a Dodge vehicle would be worth a try. Try before you buy.

The ECM will throw a code if you shut the grid heater relays off when they are supposed to be on.

 

One other thing here. If you have the Walbro hooked up to the factory wiring for the original pump. That might be your problem.
If the current draw is out side of the factory settings then the ECM will go into limp mode. May explain why you are having problems. No matter how much fuel you have going to the CP3 if the ECM only allows so much to be processed to keep the engine from dieing during limp mode.

I would try to run a seperate wire and relay from the factory wiring. Use a hot key on only trigger for the relay. Give that a try if nothing else.

Good luck keep us posted.

 

03 ant a hemi says "Use a hot key on only trigger for the relay"

What does this mean here?

 

Please double check that your truck has a relay to power the fuel pump.

I'm looking at an 03 shop manual and in it the ECM directly powers the fuel pump.

Like I said before, something is funny here. Either your dealer mis diagnosed or your truck powers the fuel pump directly from the ECM.

Having said all this, if you have 14V at the fuel pump and 20 PSI at the FF, your Walbro is probably running fine. The load on the lift pump doesn't change much from idle to WOT. You could always monitor the lift pump voltage while driving to make sure.

 

"03 ant a hemi says "Use a hot key on only trigger for the relay"

He is saying to grab a wire that is hot when the key is on and use it to power the coil in the relay to turn the pump on and off.

I'd rather use the ECM lift pump output to power the relay coil. That is how I did it on my truck and it works well.

First check if you already have a relay on your truck or if the ECM powers the lift pump directly. The owners manual should tell you and where it is. (In the diagrams with the fuse box...)

I need to know this when other people ask me Walbro electrical questions.

 

OK, I'll check the relay diagram.
Also, I put my scanner on the truck a few minutes ago . . . P0148 Fuel Delivery Error, and P2607 Intake air heater B circuit low.
I found a new Bosch 20-30A relay in the shop to use for the FP.

 

If it starts and runs well when it's cold, what in the "system" would cause it to run bad when warmed up? The pump is not temp dependent is it? What would cause a problem with the CP3 when it warms up?

 

For my walbro install i purchased a extension harness for the stock lift pump wiring. Part #4025182 You have to purchase this through a cummins dealer as it is not a dodge part.

I can now snip the end off of this harness and use it to power a secondary relay.