Unusual starting behavior, input needed...

[MMcConnell]

I have just over 51,000 miles on my 2004 2500, and up until now the truck has never given me any trouble. Since it has been getting down into the 20's and 30's here at night, when I go to start my truck in the morning, it hasn't been starting normal. I turn the key on and wait for the "wait to start" light to go out, then hit the starter. The truck fires up almost instantly, but as soon as it fires, it acts like it is only hitting on 2 -3 cylinders and black smoke rolls out of the tail pipe. It will do this for 5 - 8 seconds then it will slightly rev. (almost like tapping the go pedal quickly). From that point on, it idles as smooth as ever. It only seems to do this when it is in the 30's or below, and it always does it the first time I start it in the morning. It starts normal the rest of the day. I know that Cummins don't like cold weather, but with temps only in the 30's, I wouldn't think that would be cold enough to cause any problems. I have checked the oil level and coolant level and everything is right where it should be. I even removed my Smarty Jr. hoping that would help, but no luck. Any advice to help troublshoot this issue is greatly appreciated. Thanks in advance!

 

[rbattelle]

Just to see whether it's a cold issue, try plugging in the block heater for a few hours next time it gets that cold. If it fires up with no problems at all, that's a strong indicator that your problem is just a cold weather problem, as opposed to a more serious fuel injector issue.

I wonder if maybe you've got a burned out heater grid, which could cause the symptoms you're describing (assuming the fuel system is functioning normally).

Ryan

 

[MMcConnell]

I'll try plugging it in tomorrow before I go to work. Earlier last week when temps were in the 40's and 50's, it started fine. If it was an injector issue, wouldn't it be blowing white smoke and wouldn't it last for much longer than 5 - 8 seconds tops?



I have been thinking about the heater grid. When the truck starts, I can hear the relay kicking in and out and my voltmeter reads low for the first couple of minutes. I assume that the heater grid is working correctly, but I could be wrong. Is there anyway to check it?

 

[rbattelle]

I have been thinking about the heater grid. When the truck starts, I can hear the relay kicking in and out and my voltmeter reads low for the first couple of minutes. I assume that the heater grid is working correctly, but I could be wrong. Is there anyway to check it?

Remember there are 2 heater grids. It's possible that one is working and the other isn't. I'd check resistance across each of the grids to see if one of them is broken (infinite resistance).



I'm not sure what the correct resistance across a functioning grid is, but I suspect it's somewhere less than 1 ohm.



The voltmeter is programmed to read artificially low for the first 2 minutes, without regard to whether the current draw from the heaters is actually more than 0. The ECM doesn't have a way to measure whether the grids are actually drawing current. Instead, it simply assumes that if the relays are working, the grids are too.



Ryan

 

[VolCTD]

I've had the exact same type problem with my 2003, ever so often it will actually die. I've learned to keep it plugged in if it's below 40 and this takes care of it. The other thing that helps is a fuel additive such as Power Service in each tank of fuel.

rbattelle: Where do you check the resistance at on the heater?

 

[rbattelle]

rbattelle: Where do you check the resistance at on the heater?

Between the heater grid connection and ground. The simplest way would be to do it right at the output of the relays.



Ryan

 

[jelag]

I have several trucks... . they all sit out at night... . we don't worry about plugging them in until it is below 15* F... ... we don't see this problem..... you do have an issue... . and like mentioned above... . I think its one of the grids... .

 

[DFairhurst]

my truck had that problem an i told the dealer they said it was in my head but about 6 months later there was a flash for that in 06 i think any way after they flashed it ive had no problem but when its cold it will idle up to 1k. TSB 18-003-06 tdr issue 62 page 63 2nd tsb from top.

 

[MMcConnell]

Between the heater grid connection and ground. The simplest way would be to do it right at the output of the relays.



Ryan

It got down in the 20's last night. Plugged the truck in this morning and let it sit for about three hours before firing it up. The engine started up and ran as smooth as silk. I am thinking that it most likely is a heater grid. Can you give me any additional information as to where to check for resistance across the grids? Where exactly are the relays located? Should I have someone turn on the ignition key while I check, or can I start the engine and check while the relays are cycling? This is a new one to me, so please bare with me. Thanks in advance!

 

[rbattelle]

Can you give me any additional information as to where to check for resistance across the grids? Where exactly are the relays located?

The relays are sitting in front of the passenger side battery. I have attached a diagram (courtesy the 2003 service manual) that shows the relevant parts. The green arrows are pointing to the output of the relays, to which heavy-gauge wire is attached which runs over to the heater grids themselves on the intake manifold. You want to connect an ohm-meter between those posts (one at a time) and the negative battery wire. I suggest disconnecting the negative battery terminal before you do this, just in case.

Alternatively, you could check between the relay post and a nice clean bare spot on the intake manifold, as close as possible to where the intake horn enters the manifold.

This will measure the resistance across the entire heater grid circuit and tell you if you've got a bad grid (or possibly a bad wire between the relay and the grid).

[Note: when I say "check between. . " I mean put one lead (either one) from the ohm-meter on the relay post and the other lead either on the battery negative cable (the cable, not the battery terminal) or on a nice bare spot on the manifold].

Should I have someone turn on the ignition key while I check, or can I start the engine and check while the relays are cycling?

NO! If you're going to check the heater resistance, the engine should be off. If you wanted to check the voltage being supplied to the grids, then you'd want to have the relays engaged, which implies the engine is running (although there are other ways to do this with the engine off).

There are a number of ways to check the system out, and a number of simple things that could be wrong. If the grids check out okay (non-infinite resistance on both), then the next suspect is one of the relays (although that should set a check engine light). Or perhaps one of the relay trigger wires has gone bad (although you say you can hear both relays tripping, so that suggests they're both functioning fine and your problem lies with the grid).

If you're uncomfortable with electricity, you might consider asking someone local who is more familiar to help. For anyone who knows electricity, these kind of tests are a piece of cake.

Ryan

 

[MMcConnell]

I checked the resistance across both of the grids, and it checked out ok. Truck still has the symptoms, and now it has developed another. A couple of times here recently, I have been stopped at a stop light with the engine idleing, and all of a sudden the engine sounds like it is a powerstroke or like it has marbles in the crankcase. It will do this for a second or two then go back to normal. When I let out on the clutch to pull out, the engine stubles and nearly dies then slightly revs then runs fine from then on. I have been researching this site and have read that a failing FCA can cause symptoms like this. I ordererd one yesterday, so hopefully it will solve my problems. Is the FCA difficult to replace or are there any "tricks" that can make replacing one easier?

 

[MMcConnell]

I also meant to add that I recently changed oil and pulled a sample. The sample came back good, so I assume if it was an injector there would have been fuel in the oil. The potassium level was higher than usual, but still within normal limits.

 

[rbattelle]

Ah crap, I thought for sure it was a bad grid. But these new symptoms are almost certainly a fuel problem. FCA is a good place to start, I think. The only other possibility I see would be a rail pressure relief valve, but I'm not sure whether your symptoms are consistent with that.

Ryan

 

[mberry]

Mine does the same thing except I get blue smoke and the wonderful half burned diesel exhaust smell when she first fires up. If I don't plug in, the colder it is, the worse it is at first start unless it's cold enough to go straight to 1K RPM when started.

 

[MMcConnell]

Ah crap, I thought for sure it was a bad grid. But these new symptoms are almost certainly a fuel problem. FCA is a good place to start, I think. The only other possibility I see would be a rail pressure relief valve, but I'm not sure whether your symptoms are consistent with that.



Ryan

Yeah, I was hoping it was a bad grid as well, but that is the way my luck goes. Anyway, when I got home from work this evening, there was a package sitting on my front porch and it turned out to be the new FCA I ordered. I intstalled it this evening, and even though the engine was still warm, when I started it up it idled like it was a different truck. It idles a lot smoother and all of the excessive engine noise is gone. I test drove it and it ran great. Now, the test will be tomorrow morning when I start it up and it is cold, hopefully the rough starts will be a thing of the past.

 

[MMcConnell]

Mine does the same thing except I get blue smoke and the wonderful half burned diesel exhaust smell when she first fires up. If I don't plug in, the colder it is, the worse it is at first start unless it's cold enough to go straight to 1K RPM when started.

I had those same symptoms. As stated earlier in this post, try checking the resistance across your heater grids. A grid not working properly could cause those symptoms. If they check out ok, then most likely you have a fuel related problem like I have (hopefully had).

 

[PGreenleaf]

Well, did that baby start OK this AM??

 

[MMcConnell]

Problem Solved! I started the truck this morning and it purred like a kitten, idled as smooth as silk and I could not be happier. The FCA was the culprit. It is amazing the effect a faulty FCA will have on the engine. I had the CP3 replaced under warranty early in 2008 due to a leaking seal. I wander when DC replaces a CP3, if the CP3 has a new FCA in it or if they reuse the FCA from the old pump. Anyway, problem solved and thanks to everyone who helped me with this issue, this site rocks!

 

[PGreenleaf]

OK What does FCA stand for??

 

[rbattelle]

OK What does FCA stand for??

Fuel Control Actuator. It's mounted in the back of the CP-3 and controls how much fuel goes to the pumping chambers and how much goes for lubrication.



Ryan