Hey Gang, 

 

I've managed to get Thor running for the first time in 2 years. I opted for a stock fuel pump for right now since I'm missing parts yet for the AirDog 150 fuel system I've got I'm looking for a bracket for the pump. I have good positive pressure for the CP3 injection pump. I need to find out what the misfire and studdering are about. Cold start it's a bit long cranking not bad. Once it starts it runs rough and smokes white. I've got a set of @dieselautopower +50 HP injectors installed and had them sent back to DAP and found one injector had an issue and was repaired and sent back. Then I ordered a set of o-rings and replaced all o-rings on injectors and cross-over tubes.

 

Once warmed up all roughness is gone. It runs good and strong for what it is. I can even do the oil cap test and the cap does not even move. I'm trying to figure out the cold idle roughness and warm up smoke them once warm it drives and runs great. Even yesterday I drove to town and got 50 dollars of fresh diesel fuel to make sure its got enough cetane and pour point depressants. Currently 39*F here. Last problem in this category is the grid heater light came on yesterday and dinged 10 times signaling its high flow rates of the CP3.  It idles at about 7,9xx PSI of fuel rail. At 1,500 RPM its pumping up to 11,8xx roughly and appears the fuel rail is building good pressure. 

 

With Thor being my project I plan on writing articles as I get things figured out. So anyone give me a hand on this? Monday I'm going to put insurance and registration on Thor and he's going to become my daily runner. Why? Beast finally needs shop time and the rear main seal is leaking. Thor becomes the primary rig for now while I gather supplies for Beast and get my help here to remove the transmission and transfer case so we can access the rear main seal.

 

 

Thor is also going to lose the heavy flat bed and front bumper soon. I'm going back to the lighter factory box and tailgate then factory bumpers and ditch close to a full ton of steel. Thor is fat at 9,300 pounds even empty.

Here we go.

 

There will be lot more photos and article wrote. 3rd Gen article is building.

Whadda ya doin'?

 

- John

9 minutes ago, Tractorman said:

Whadda ya doin'?

 

- John

 

 Injector inspection. 

 

I managed to get all 6 injectors removed. I'm going to town for a scotchbrite pad and brake cleaner.

Update...

 

So i pulled all 6 injectors doubled checked the fitting of all parts and made sure all parts were of good condition. Now brake cleaned all parts and mating surfaces to bet sure everything was clean and job is done absolutely right. Now during reassembly I had the terminal post snap off the #1 injector and I'm going to have to send this one out to be serviced and repaired. Sadly I got a delay to fix one injector and already called @dieselautopower and talked to Mitchell and got everything ready to ship out tomorrow.

 

Temporary pause button on Thor for the moment... 

So, at this point it doesn't sound like you are seeing anything that would be contributing to the symptoms you are having - is that correct?  Bummer about the broken injector. 

 

- John

Still the logics of the ECM is calling for high return rate possible misaligned injector / crossover tube not seating. This is why the grid heater light and chime. Which also part of loss of prime issue possible all relayed but need to finish and try starting but now wait for mail back and forth.

On 12/31/2024 at 3:58 PM, Mopar1973Man said:

The lift pump at key on rose to 14 PSI during grid heat. Then, during cranking, the rail jumped to 17,xxx PSI and continued to be hard to start. Now, I stopped and unplugged the FCA and tried again. The lift pump again rose to 14 PSI during grid heat. Then cranking jumped to 17,xxx PSI, and I also continued to crank until it started. The only difference was the FCA disconnected rail stayed max pressure where after starting with FCA would drop back to about 7,xxx PSI roughly.

 

The above post indicates that fuel rail pressure rises quickly to well above 4,500 psi, but the engine continues to crank a long time before starting.

 

On 1/1/2025 at 12:09 PM, Mopar1973Man said:

The lift pump comes up fairly quickly to 14 PSI then the rail starts at 84 PSI engine off and key on. Now when lift pump hits 14 PSI quickly order the rail bounces from 84 PSI to about 1,1xx PSI continues to crank then the  surge hits at 12,xxx to 13,xxx PSI and the engine starts the pressure settles at 6,xxx to 8,xxx pulsing.

 

This post indicates that fuel rail pressure stays well below 4,500 psi during cranking and the engine won't start until the pressure suddenly jumps above 4,500 psi.

 

Which post is correct?

 

- John

Both really. It is random depending on how deep the rail drains out. I've left both the lift pump gauge hooked up and typically watch the live data tool. Again numbers vary based on how much the rail drains off. 

 

Those are two different run cycles showing the changes from one start cycle to the next. 

 

Since this article I've been fighting this..

 

Edited January 8Jan 8 by Mopar1973Man

Project Thor continues... Mark found me a set of bumpers, 8 foot bed, and tailgate and swapping the flat bed and winch bumper. I'll post up photos what we see when I get to Jordan Valley, OR.

 

Made the trip out to meet my guy on the bed trade I'm doing. I'm trading the super heavy winch bumper and the steel flatbed with toolboxes. Here is the bed I'll get.

 

 

Yeah it's rough but workable. Now to get my injector back in Thor so i can roll it out of the shop. 

Once you have the bed do something around the hile for the gooseneck hitch. Mine rusted out all the way around that. I now have a hole 20" front to back and all the way from wheel well to wheel well. They cut it out for the hitch but didn't seal it or rust proof in any way.

 I now have a rubber bed mat screwed to the bed floor to cover it so I don't fall through. I have another bed for the truck, just haven't had the time or money to repaint it and swap them. (The spare bed is black, truck is silver)

I was just talking to Mark about the bed floor and my idea of fixing that quick.

 My "new" bed has a small square hole innit for a gooseneck as well. I'm going to cut a piece of bed floor out of the old one and section it into the new one. The new bed has been rhino lined so once the patch is in I will go to rhino liner and have it filled in and spray the patch area from the bottom also. That way it us sealed on both top and bottom.

I've got a sheet of metal here I can cut a full width chunk and tack weld the piece in place. Then straighten all the remaining edges and weld them down to the sheet metal. Now like get a gallon of Hurculiner and cover the host of sin on the bed bottom.

So... I've got the one injector back from @dieselautopower seated and installed in the head again. This is nuts I'm losing prime instantly. I'm still fighting loss of prime issues which is nearly instantly. If the engine stalls or shut off it impossible to start again, super long cranking. 

 

I'm still seeing about 2,xxx PSI swing in pressures at idle on the rail I'm getting both 5 chimes and 10 chimes grid heater light. If driven slowly under 40 MPH it will not set the grid heater light. Extremely hard to start hot. Once the grid heater light is on the rail pressure is forced to 19,xxx to 20,xxx PSI all the time your driving.

 

I've even changed fuel filters just for the sake of it. It was dirty looking but not the cause. Lift pump pressure is more stable but still very possible to suck it down to ZERO PSI of supply pressure on a WOT run if the grid heater light is off. 

 

I've pull inspected these injector twice now. Still have a rough idle miss either warmed or cold. Blue smoke from one cylinder while idleing but there is no real blow by at all. The cap lays in the hole just fine and doesn't jump out. During the rough idle periods it will jack the rail pressure from 6,xxx roughly to 8,xxx PSI then when is smooths out it drops again. 

The lift pump pressure falling to zero at WOT may be trying to tell you something.

 

I think it is time for a different approach.  I would rig a five gallon container with fuel supply and return.  I would anchor the container in the bed of the truck and go for a test drive and document the results.

 

- John

This sounds like a rail pressure relief valve sticking open. 

I’d recommend taking the drain line off the PRV on the rail and confirm it’s not leaking down. They pop off at a high pressure so if anything is coming out it’s not good.

 

Also, if your losing prime in the head you can take the return line off the back of the head and measure how much is coming out in a graduated beaker. If it’s too much the mating surfaces on the cross over tube to the injector mating face may be the issue.

 

 

Here is some of the random wild swings in pressure at idle.

 Ok, I'm a novice with common rail. Would the firing of the injectors cause a fluctuation? I would think so, to this extent though I'm not sure.

 Also, what is the preferred pressure from the lift pump? 

On 2/10/2025 at 3:43 PM, Mopar1973Man said:

Lift pump pressure is more stable but still very possible to suck it down to ZERO PSI of supply pressure on a WOT run if the grid heater light is off

 This would cause me to question pressure and or volume from the lift pump. Is there a "big line kit" between the lift pump, oem filter and injection pump?

35 minutes ago, Doubletrouble said:

 Also, what is the preferred pressure from the lift pump? 

 

Pretty much the same as our VP44 engines.  When my VP44 replacement and in-tank lift pump mod was done by the dealer under warranty, it was replaced with the same in-tank pump that was used for the common rail system.

 

35 minutes ago, Doubletrouble said:

This would cause me to question pressure and or volume from the lift pump.

 

I agree - that's why I am recommending temporarily plumbing the lift pump to a remote fuel container and then going for a test drive.

 

- John

Edited February 12Feb 12 by Tractorman