Hard starting

[william lopoulos]

Hello, I have a 2006 Dodge 2500 5.9 Cummins 24 valve. Lately it has gotten very hard to start. Had weak power too, replaced fuel filter and power seems OK even right after a cold start. Connected diag tool and pressure is dancing around 6000 at low idle. Gave it a little pedal, and it went up to 8000.

Once it starts, it restarts OK unless it sits for a while. It has around 350K miles (even original transmission). Never plowed tows very rarely, mostly an expensive commuter vehicle. It actually shifts pretty well too... but I know that won't last.

Starting seems to be getting rapidly worse. Do I need a new CP3? What other tests can I do?

thanks

bill

 

[Darkbloodmon]

A bit more information on the hard start would be helpful.

Do you have any gauges?
Is it just turning over?
How long are the cranks? Ambient temp?
Is your starting system up to par or weakening?
Smoke color on start up and for how long?

 

[william lopoulos]

I don't have any gauges beyond factory. The batteries and starter are in good shape, cranks very rapidly, just WAY longer than normal. Normally about 4 cranks (twice the number of my prior 12-valve), now takes about 16 or more. Ambient is around 50 or 60 degrees, springtime in New England. I haven't observed any smoke yet upon starting. Seems to help if i give it some accelerator, but that is difficult to say. And I always wait for the heater light to go out. I have a DTC code reader, no codes.

If I then start it, let it run, and then re-start it it starts much better. If it sits, then it goes back to hard starting.

Do I need a new/rebuilt CP3 pump?

thanks

bill

 

[Darkbloodmon]

I don't have any gauges beyond factory. The batteries and starter are in good shape, cranks very rapidly, just WAY longer than normal. Normally about 4 cranks (twice the number of my prior 12-valve), now takes about 16 or more. Ambient is around 50 or 60 degrees, springtime in New England. I haven't observed any smoke yet upon starting. Seems to help if i give it some accelerator, but that is difficult to say. And I always wait for the heater light to go out. I have a DTC code reader, no codes.

If I then start it, let it run, and then re-start it it starts much better. If it sits, then it goes back to hard starting.

Do I need a new/rebuilt CP3 pump?

thanks

bill

CP3 needs to supply aprox 4K psi to the rail for starting. Can you monitor rail pressure while starting? If not, with caution unplug the FCA and try starting it, FCA is a metering valve and it will default to wide open un plugged meaning max pressure. If it fires over without issue I'd be leaning towards CP3 if it's original.

You mentioned after getting it to run turning it back over was normal. Are you talking cold starts versus hot starts?

If your injectors are as old as your CP3, they could have leaking tips taking prime away from high-pressure side while it sits over night. You can observe this with smoke color (Blue White) once you get it running, If smoke doesn't clear after a min depending on your altitude and temp, this could signify a bad injector but further testing would be recommended to be sure.

 

[bcbender]

My 04 did similar things that last year or so and it was always on cold starts (or if it had been sitting for awhile) Some times it would blow a big puff of black smoke when it caught and usually leave some soot / condensate / fuel? on the wall!!... Mine only had 200k on it but it was all original sans two injectors that were done under warranty at 100k. I traded it in on my 20, but was leaning towards injectors at the time and decided that a new CP3 and injectors was not in my future so I let her go. I will be interested in following this to see where it leads.

 

[william lopoulos]

OK, just went out with the scan tool and watched live-data while it started. Kept resetting on me, I know I probably need a better scan tool..... Anyway, whie it was starting, I saw around 1500 PSI. Once I stopped cranking, it dropped right back down to around 27 within a second. I repeated this several times, and the few times the tool didn't reset, the high-pressure was about the same. Then I let it start, not even a puff of smoke that I could see.

The starts I mentioned above were (I guess) hot starts. Start it, let it run, then start it right again.

From your description above, it sounds like I need a rebuilt CP3. Do you concur? I have watched a couple of videos on this, doesn't look to hard. There does not seem to be a special timing procedure, timing gear is captive. To do the swap, I would need the pump, special gear puller, and a replacement access hole cover (in case I crack mine.) Pull it out, put the new one in. Is that all there is to it? Or have I over-simplified?

Thank you so much, this has been hugely helpful. Never thought to check pressure while I was cranking!

bill

 

[Darkbloodmon]

That pressure is very low, I would pull the FCA and retest to be sure, how old are your injectors? If you're looking for a replacement stick with a new one from Bosch. If your injectors are just as old, test them.

Pull it out, put the new one in. Is that all there is to it? Or have I over-simplified?

The process is simple to write out but more technical to perform in my experience, I put on an S&S Super Sport 6.7 CP3 on my 03 5.9 and I struggled even though I removed all the components in the front of the engine down to the timing cover (additional repairs and reseals). Make sure you have the flex heads and extensions you need for the rear nuts and be careful with them they are studded into the timing cover.

 

[william lopoulos]

I pulled the FCA and it started right up. Reconnected it, and it started REALLY hard. So I am assuming that it is the CP3?

 

[Darkbloodmon]

Sounds like a safe bet to me.

 

[william lopoulos]

Thank you so much, I will get a pump on order and let you know how it goes. Hope it doesn't die in the meantime

 

[bcbender]

Hope it doesn't die in the meantime

Its not a CP4.2.2.2.2

 

[Darkbloodmon]

Its not a CP4.2.2.2.2

350K on an original CP3 is pretty stellar in my book.

 

[jghflys]

If it started promptly when you pulled the FCA connector, the CP3 is generating enough pressure. Could the FCA be bad? Cheaper and easier than a CP3.

 

[Ozymandias]

If it started promptly when you pulled the FCA connector, the CP3 is generating enough pressure. Could the FCA be bad? Cheaper and easier than a CP3.

I second this.

 

[CoastyAV8R]

Yup on the FCA, read this and it will help you diagnose your issue.
If the Cummins 4932457 FCA / Fuel Control Actuator is not correctly functioning; this results in the Engine Control Module / ECM cannot determine what is the actual fuel flow rate being supplied to the CP3 Fuel injection Pump. In most cases, people first know there is an issue when they have a hard start or no start issue because the FCA will not allow the pump to build pressure to start correctly. However, by the time this symptom occurs, the truck has probably been delivering less than the genuinely desired amount of fueling for a while already as the FCA is a simple spring design that many times takes a rather slow death and not an immediate failure. The Engine Control Module / ECM uses the fuel control actuator to control the fuel pressure in the common rail Dodge Ram diesel. The Fuel Control Actuator is an electronically controlled solenoid valve. The ECM controls the amount of fuel that enters the high-pressure pumping chambers by opening and closing the FCA based on demand. The FCA is the device that controls the fuel pressure delivered to the common rail to provide fuel delivery rates.

What are the symptoms of a failing 5.9L Cummins Fuel Control Actuator - FCA?

• Hard Starts
• No Start Condition
• Rough Idle
• A Rattling Noise from the engine, which sounds like Fuel Knock.
• You have decreased the engine power output level.
• Engine operation is rough.
• Engine RPM surging

A faulty fuel pressure regulator causes these symptoms. Replacing your 5.9L Cummins regulator can resolve your problem.

How to test if your Cummins 4932457 Fuel Control Actuator is working:

If you're experiencing hard start or no start issues, one easy way to confirm whether or not the FCA is causing the problem is to unplug it, thus eliminating any metering simply. The Fuel Control Actuator is a one-inch silver cylinder located on the backside of your CP3 fuel injection pump block. Presuming the truck starts, immediately turn it off as you will have full pressure running to the fuel rail, but at least you have reasonably high certainty that the FCA was causing the issue.

 

[Darkbloodmon]

If it started promptly when you pulled the FCA connector, the CP3 is generating enough pressure. Could the FCA be bad? Cheaper and easier than a CP3.

Good catch, I overlooked that. I agree cheap easy stuff first. You could test cranking pressure after swapping the FCA to verify you're seeing the pressure you need to fire off.

In thinking about that point, How worn does a pump need to be to not fire off at max output pressure?

And what kind of mileage can you see on a 5.9 CP3 with a stock fuel filtration system? A lot of people on Duramax forums had noted anywhere from 160K to 200K for the replacement interval as pressures were dropping off. I know it's not an apples to apples but none the less it's a CP3.

350K is a good bit if this is the first issue. My 03 had 207K (stock fuel filtration till 210K) when I got it and the CP3 has been leaking diesel out the weep hole until I replaced it at 230K.

 

[jghflys]

I got it and the CP3 has been leaking diesel out the weep hole until I replaced it at 230K.

I had 232K on mine when I changed it because of oil leaking from the weep hole.

 

[cerberusiam]

First FCA, then injectors. At 350k and no extra filtration or additives you are at EOL for injectors in that year of truck.

 

[william lopoulos]

Well..... I wish some of these responses had come sooner! I replaced the pump (comes with a new FCA) and it is starting fine. Not quite what it was when it was new, but relatively normal starts and with power. But realisticly, how much more life could the pump have had? Anyway, it is done, and I suppose injectors will be next. I am not looking forward to that, especially for cyl 5 & 6 as they are pretty deep under the cowling.

BTW, replacing the pump couldn't have gone easier! I was doing it alone, so the hardest part was the nut on the shaft. Spotted a right-angle 1/2" drive impact driver for not too much money and that did the trick.

Will I be able to get out those rear injectors and tubes? Keep in mind I am in the northeast and have to deal with lots of corrosion.

thanks

 

[Crunch]

First FCA, then injectors. At 350k and no extra filtration or additives you are at EOL for injectors in that year of truck.

I second Cerb's suggestion. I had the same symptoms at 340K, and had the connector tubes reset. Worked great for almost a year, then an O ring on an injector started leaking fuel into the crankcase. Had the injectors replaced when that happened and that's kept it running for another 40K so far. Still the original FCA, though. So far no problems with that, either. One other suggestion, at the risk of starting another injector discussion. I was worried that the problem was the CP3 so I had the Cummins shop install the Bosch reman injectors. Had I not had the concern about the CP3 I would have got the new Bosch injectors instead for the additional $$. I haven't had any problems with the remans, but search this forum and you can spend a few evenings reading 10 years of injector discussions. Long story short, you will either be Team Bosch Reman, Team Bosch New or Team BBI. Read all the discussions, make your choice wisely and don't look back. Godspeed, my son. Godspeed.