Ramdan04

I am new to this site, and also have only owned my Ram since May of 2012. It is my first Ram Truck, and I am still learning about it.

I have a 2004 5.9 Cummins

About a week ago I went to start up the truck and it wouldn't start. I plugged it in and after about an hour it started. So this past week as long as I had it plugged in it would start right away. I would have it out for the day not plugged but it runs fine until I let it go over night without it plugged in. The temps here have been 20-40 and it has started up just fine all winter with colder temps and not plugged in every time.

I have noticed that it seams the grid heater does not stay on as long as it used to. I will turn the key a few times and let it heat up before trying to start but that still does not seem to help. It will only start after I have had it plugged in. What tells the heater that it is warm enough to shut off? I am going to check some voltages and do an amp reading later today, but any input would be great. Thanks

jhenson

That truck should fire easily in those temps. Sounds like you have injector issues my friend. Hate to be the bearer of bad news.

The grid reads off of the Ambient Air Temp. sensor in your intake duct and also from the Mass Airflow Sensor on the intake manifold.

Ramdan04

Why do you think the grid heater isn't staying on as long as it used to on a cold start?(without it plugged in) I am planning on going taking an ohm reading of my ambient air temp sensor to make sure it is reading correctly.

9812vram

That thing should fire up without the grids in -6*c temps, no problem. Not trying to be a jerk, but I think the difference you're seeing in how long the light stays on is your imagination... If your batteries are in good shape, I'm with jhenson - you will likely be breaking out the credit card for some new injectors in the not-so-far-future... Better check codes, lift pump pressure, the FCA and rail pressure sensor first though . Your dealer and a few other repair shops can do a kind of electronic injector test too. Cylinder contribution test I think is what it's called. I generally don't go that far though - if the above mentioned items check out, I just replace the injectors.

Ramdan04

Thank you both for your input. If I do need injectors, are there injectors you would recommend? Thanks again.

jhenson

If you don't much downtime in mind, you can opt for F1 injectors through one of Don's vendors to be shipped to you with a rather large core charge until your's are sent in and accepted as good (rebuildable), or you can pull yours out and send them in to Don at F1 or Exergy Engineering for a full inspection and build with nozzle sizing of your choice.

I sent mine in to F1 on a Monday morning and had them back in the truck that Friday afternoon......but, I also live about 150 miles from F1, hence the quick turnaround time. It is a rather large amount of money to do this job but if you go to either of these companies it will be worth it in the end.

You can also get reman units from a diesel shop for a bit cheaper but they are known to fail prematurely....why, who knows.

Hintonc393

Just so you know the injectors will start to bypass fuel back to the tank as they get older which makes the injection pump work harder to provide enough pressure to satisfy the ecm and begin injection. Your injectors have reached the limit of what the CP3 can provide at cranking so it will no longer start when cold. This is one of the number one signs of injectors failing on a CR. If you have a way to check it watch your fuel pressure on cranking, I think that the ECM wants around 5k psi before it will start injection.

9812vram

I've only installed two sets of CR injectors. I put in a stock set of remans from Pensicola Diesel (not my choice) for one fella... Caught a sale and they were cheap as cheap, but they don't seem to run as crisp as they should and they smoke a little. I think "cheap" is the key word there. The other set were "stainless" bodied +50hp injectors from USA Freedom Diesels. They have almost 40,000kms on them now and he sure likes them. The service we got was really good too. I called them but no one answered. 20min later they called me back - I never even left a message! Who does that? Needless to say I was impressed. They were very helpful with a couple questions too and gave me 30 days to return the cores.
Seems like there's quite a few options for you, these are the only two I have experience with...

Ramdan04

I have learned a lot about my cummins this first year I have had it and am still learning. Just to ask a dumb question, why does it start up just fine when it's plugged in as opposed to not starting when it isn't plugged in? Thanks for the advice you all have given.

jhenson

As far as I know....it's all about tolerances. They are so tight in these common rail injectors that even the slightest bit (temp changes) can throw them off. Someone please correct me if I'm wrong. BigIron(I believe is what he goes by) seems to know his stuff.....might want to shoot him a PM on this.

Hintonc393

I am not 100% sure, I would think it has a lot to do with the clearances in the injector and the duty cycle of the FCA due to coolant temp. When this happed to my truck it began slowly, the truck would take longer and longer cranking times to start. Once the truck started and ran for the first time that day it never gave me any trouble.

Have you retorqed your crossover tubes yet? That will cause the same problem. I am sure you have seen other posts about this problem.

The other big cause is batteries. As time goes on you don't notice your truck turning over slower and slower which in turn turns the CP3 slower causing longer cranking times.

Hintonc393

And there are no dumb questions here, none of us were born knowing this stuff. Do a search first and if you don't find what you want ask away, no one will beat you up on this forum.

Hintonc393

This was taken from a write up on TDR.

Let's talk about the long crank issue. This is generally created due to the CP3 injection pump not being able to pump up enough pressure in the common rail to fire the injectors (around 5200psi). The first thing to check is the total fuel return volume to see that it doesn't exceed about 30 ml during a 10-second crank period. Sometimes you can cure the problem by re-torqueing the fuel delivery tubes. Next, check the individual injectors to see that they are returning only 2-6ml during a 10-second crank period. Any injector with a return volume in the 12-14ml range during a 10-second crank period needs to be replaced. This happens when the check ball wears so that it doesn't seat correctly which, of course, causes a leak. To confirm the problem, with the engine cold, cap off each injector during cranking and see which one allows the engine to fire up.

I noted that TDR writer Andy Redmond had presented this Q&A back in Issue 66. The following is how he went about the diagnostics and repair:

"Recently, a 2005 truck arrived with a hard starting problem. Other recent repairs included two remanufactured injectors, but shortly after the injectors were installed the owner complained the hard start problem worsened as did his poor fuel economy. The scan tool was connected and no diagnostic trouble codes (DTC's) were present. The batteries were tested and found to have a good charge. My next step was to monitor actual and desired rail pressure (psi) during the cranking attempts. After several consecutive cranking cycles the scanner showed pressure increasing from 1000 psi to about 4,000 psi at which time the engine started. Why will the truck not crank until a certain pressure level is met? Simple. At low pressure the ECM programming does not command the injector solenoids to energize. A light misfi re was observed at engine idle.

Ramdan04

Thanks for the additional info Hinton. I am planning on taking it to a shop since I don't have the resources to make a proper diagnosis. I will let you know what they find.

w.tx iceman

Highjack. I didnt know don would send out injectors first. what is his core charge?