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.

I was really hoping someone would give me a bit of aid with this misfire issue somewhat. Baffling... 

Finally, yesterday got the legal stuff done to use Thor again. Suzanna and I went to McCall in Thor. Here is what happened. Thor was plugged in and parked in my garage. Fired up but long cranking. Idle smooth for a short time then starts to miss. As we left I managed to start building boost and blew the intercooler boot on the turbo side. Turned around and returned quickly and fixed that took about 10 minutes. Once fully warmed up I runs good. We stopped at Ridleys in McCall for misc grocery things. Came back to Thor loaded up and tried starting and very long cranking. Between attempts I allowed the lift pump to run and prime the fuel system again. Started again. Then we stopped at a bank and sure enough Thor was hard starting again. The last tidbit the grid heater light came on again on the trip up the mountain. I need to figure this puzzle out. 

 

Any suggestions?

Ok. I did manage to figure out more. The grid heater power lead was disconnected from the battery on the passenger side. Finally got a code for a P2609 code for grid heater performance. Then found on CF someone mentions the chime count. 10 chimes is fuel-related most likely and 5 chimes is something else but he didn't say. When all codes are cleared it runs strong but trip the grid heater light it is in limp mode.  I cleared all error codes and took Thor out  for a test drive and ran great but just before I got home and pulled in the driveway I chimed again and lit up the grid heater light. 

 

Still, fighting hard starts either warm or cold, loss of prime? 

My knowledge is fairly limited regarding the 3rd generation trucks.   If you don't already have these tools, a couple of tools I recommend would be a scanner that can read commanded rail pressure and actual rail pressure, and an injector block off tool.  I have used them in the past and they have helped me diagnose a faulty injector. 

 

I know that when the engine is cranking, if the fuel rail pressure is below 4,500 psi, the ECM will not command injectors to fire.

 

- John

 

I have both tools. Rail at idle and at RPM listed above. These injectors just came from @dieselautopower a year ago and truck has not been driven but one 70 mile trip and parked and sat for another year due to a bad lift pump had zero pressure and hard start. I'm going to put a Schrader valve in and be able to test the lift pump and verify fuel pressure. I'm also going to verify the crossover tubes are tight and seated correctly.

 

@Tractorman if you find the wait to start chime numbers let me know. So far I've found out 5 and 10 chimes are different. I'm assuming 5 is grid heater issues?

Edited December 25, 2024Dec 25 by Mopar1973Man

2 hours ago, Mopar1973Man said:

Rail at idle and at RPM listed above

 

I would be more interested in observing rail pressure during the long cranking periods, not when the engine is idling.  If the rail pressure is well below 4,500 psi during long cranking, then you know that you have fuel bleeding off somewhere.  If it stays around 4,500 psi or higher during the long cranking period, then you know something else is going on.  Either way, it offers information.

 

As far as the chimes, are the "grid heater light" and the "wait to start light" the same item on a 2006 common rail truck?  Here is what I am finding:

 

WTS and 5 chimes - "The WTS light and chimes are a leak detection DTC, which means that the fuel calculation between the used versus demanded is out of range.."

 

- John

Edited December 25, 2024Dec 25 by Tractorman

What about the factory these are +50HP injectors? How is this measured to determine if it is truly out of range?

 

Oh Merry Christmas...

So I got out and managed to work barely 3 hours and my back and hips are screaming... I'm going back over all the crossover tubes and trying to make sure no debris is in the seats and then torquing all the crossover nuts to 37 ft/lbs as stated in the FSM. Give me a bit of time by tomorrow I'll give it another shot to finish this up and see if the system holds prime better. Also I found a banjo bolt with the Schrader valve and make it easier to access fuel pressure for testing purpose. 

 

Rail pressure at idle.

What is the rail pressure while cranking during a hard start?

 

- John

I'll check in the morning. I just had another hard start just getting it started to move back in the garage for the night. I finished pulling and reseating the crossover tubes and that helped a bunch. Easier to start after warm and runs with more power. Now I've had one time where the grid heater popped on with 10 chimes. Pulled over and pulled out the OBDII tool there were no codes and the grid heater light went off on its own.  Now if I turn the engine off and reconnect to the CANBus I can clear the codes that don't exist and the grid heater light goes off. Nevertheless, the little work to get the crossover tubes retorqued and checked I do have a few tubes that might have some damage causing the hard starts. Hence why I posted the thread size of the crossover tube. 14mm x 1.5mm. When I can buy 2 crossover tubes so I can replace the questionable ones. 

I'm going to have to start from ground up. I'm not holding prime very long. Went to town and got the grid heater light twice 10 chimes. Stop at the rest area and cleared the light as was like total loss of prime in seconds now.

 

I've got to check pressure during the hard starts which I'm sure the CP3 is dry a drill going to show zero pressure during crank.

It sounds like you are on the right path.

 

- John

 No external.leaks though? I'm beginning to lean towards the cp3 going out. Something internal in the cp3 must be allowing air in to loose prime. 

3 hours ago, Doubletrouble said:

No external.leaks though?

Correct no leaking fuel on the ground or externally. I'm looking at the over-pressure valve, possibly still debris or something fouling alignment of the crossover tube. 

 

3 hours ago, Doubletrouble said:

I'm beginning to lean towards the cp3 going out. Something internal in the cp3 must be allowing air in to loose prime.

Funny part last run the CP3 was pinned at 20k PSI and working hard core to feed the truck and the leak at the same time. Weird... Typically grid heater light is tripped as I change from heavy throttle to light or coasting. Then it sets the light chimes 10 times. To regain power I've got to pull over reset codes but no codes could be found. Press ERASE and the light goes out. During an erase command the engine cannot be running. It takes less than 60 seconds to erase and then the super long hard start to resume. I did this at the rest area south of Riggins, II but less than 2 miles light came on again.  Light comes on more so when coolant is over 200*F. (204 to 210*F). Cold the light stays off still really hard start. 

I would still be interested in the behavior of the fuel rail pressure while the engine is cranking during a hard start.  I don't think you have done that, yet.

 

If the fuel rail pressure is low during the hard start, remove the fuel control actuator electrical connector and see if the rail pressure rises when cranking the engine and the engine starts right away.  If it does, you have a high return flow rate problem somewhere - not an "air in the fuel" problem.

 

- John

Ok. @Tractorman

 

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.

 

Now on the run the lift pump runs right down to ZERO pressure on a WOT event heading towards 80 MPH. Rail stays pretty much at 19,xxx to barely 20,xxx PSI. Shut it off for a very short time say 1 minute and start again same thing the lift pump comes up and rail jumps up in pressure and continues to crank.

 

Funny part is it runs great. I can spin the tires on launch from the driveway. Good power and everything. Just if the grid heater light comes back then it might limp mode the power.

 

I would love to have the true definition of that grid heater light and what it means and what is monitored.

Edited January 1Jan 1 by Mopar1973Man

2 hours ago, 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.

 

Interesting - not what I was expecting.  I was expecting to see rail pressure below 4500 psi while cranking during the hard start.  That would have made sense as the ECM would not have turned on the injectors at that low of pressure.  Also, it would have coincided with high fuel return rate.

 

So, if I am understanding correctly, you are getting fuel rail pressure above 4500 psi immediately, even with the FCA connected and the engine still won't start.  So, the question for me is, why isn't  the ECM telling the injectors to fire right away?

 

This is where my lack of fully understanding the details of how a common rail fuel system works comes into play.  If this were my truck, I think I would want to know what all has to be in place before the ECM will tell the injectors to fire.  Example:  could an engine rpm sensor cause the ECM to not fire injectors, or could the fuel pressure sensor cause the ECM not to fire injectors?, etc.

 

- John

 

 

 This may be a shot in the dark but a buddy's older chevy (1993) diesel won't start until the engine oil pressure rises above a certain value. Is this maybe something cummins or dodge did as well?

I'm pretty sure now it's a loss of prime. Somewhere in the crossover and injectors yet. I managed to get all set up a graphic display of rail pressure. 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.

 

Changed the supply banjo seals on the CP3 and stopped a weeping leak. Then for fun pulled the fuel filter to look at filter condition and lid seal. Filter needs changing and the seal I changed from a salvaged seal. The crank time is greatly reduced but still could trip a grid heater light on only deceleration and its a 10 chime account again. The grid heater light can be reset.