Dodge Ram Cummins Starting issue

[MuleShack]

On the 05' Ram 3/4 ton, over the last few months it seems to take 6-8 turn overs before it fires. Even in the heated garage starting cold and refiring when shut off warm...it seems to take longer when firing warm.

Normally it will fire off on the first or 2nd crank and started last winter on Red lake in -40 degree weather. this year it wouldn't start at -27 and had to plug it in.

Anyway I took it to a shop to have them run a diagnostic on it to see if there was anything that stood out. The thing they came back with was to charge me $125 for a PCM update. Evidentally my last flash ended in "D" and the new ones are up to "H" or something. I didn't get it done at the time because their update equipment wasn't working.... The way I look at it is the current flash has worked fine for the last 5 years, why would I need a new "update" to allegedly solve the starting issue. Is this PCM update neccesary?

I guess I would rather spend that $125 having them look for a bad injector or a leak in a fuel line not?

What else would cause the weak starting? Once if fires, it runs fine. I did check the heater grid and i have power running to that on both lines so assuming that is working.

Thoughts?

[Macgyver55]

I did check the heater grid and i have power running to that on both lines so assuming that is working.

Thoughts?

Never assume anything....I'd disconnect the wires and test the grid with an ohmmeter first.

[MuleShack]

Good point!

I'll try that tomorrow.

[Valv]

The quickest way to check if your heater grid works is to notice the drop in voltage when starting it cold. It is very noticeable, especially when you have headlights on, you'll see they will get dimmer for 30 sec then back normal and so on. I assume the shop would have noticed it if it was not working, but you never not some dealers these days.

Be sure your truck idles up to 1000rpm automatically when below 40 degrees.

Did you ask them to enable the PTO option ? It's very handy this time of the year.

It will let you raise engine idle up to 1400rpm by using the Cruise controls.

[MuleShack]

The quickest way to check if your heater grid works is to notice the drop in voltage when starting it cold. It is very noticeable, especially when you have headlights on, you'll see they will get dimmer for 30 sec then back normal and so on.

I didn't get a chance to check this out today, but yes the guage drops down to 12 volts or less for about 2-3 minutes after starting and then comes back up. If it is suppose to only be 30 seconds then possily an issue?

I may pull the heater grid off tomorrow just to check it out and make sure it is cleaned and test the ohms etc.

[MuleShack]

Is this PCM update neccesary or just a quick way to get money from people?

[311Hemi]

To me it sounds like a reach by the dealer, especially if it's been running fine on the normal flash. That's just my feeling.

You should jump on over to the Cummins Diesel Forum and do some searching there under the 3rd gen section. There are a lot of posts with symptoms as you describe and possible fixes. Sounds like it could be a number of things, worst case probably a bad injector(s).

On my 03' the heater grid cycles on and off for a couple min. As Valv said my lights dim when it cycles and once it's done I see the voltage jump up to normal.

[MuleShack]

I just checked the ohms and have readings of 200 and 225 if I am reading it right.

Going to pull intake line off to see what grid looks like inside now.

[Bigtom]

I know the dealer charged me 120.00 just to hook up the computer to my truck just to turn on my fog lights. I believe that the pcm controls the starter.

[Valv]

You won't see much, they look like a "potato slicer" (as seen on TV ).

Check the 2 relays on fender, these might be more at risk.

[Whoaru99]

I just checked the ohms and have readings of 200 and 225 if I am reading it right.

Going to pull intake line off to see what grid looks like inside now.

I don't know for sure, but just based on electrical properties/function 200-225 ohms does not seem correct to me. Sounds much too high.

Using Ohm's Law and power formula, 12 volts divide by 200 Ohms gives only 0.06 amp. 0.06 amp multiplied by 12 volts gives only about 0.7 watts of power. That's not going to heat much air.

I know it's a completely different engine, but the service manual for the Cummins 5.9L 24-valve says each grid heater will draw about 95 amps. That implies a resistance of roughly 0.13 ohm.

[MuleShack]

Not sure how to read ohms, but I had it on the 10x setting.

It did start for me this morning after sitting outside overnight with no plug in at -28 on the thermometer, so it seems to be working.

[311Hemi]

I know it's a completely different engine, but the service manual for the Cummins 5.9L 24-valve says each grid heater will draw about 95 amps. That implies a resistance of roughly 0.13 ohm.

His 2005 should be a 24v 5.9 as well.

[Whoaru99]

Heh...yeah. For some reason I had it in my head it was a 6.7L but I guess that wasn't until a couple years newer.

[MuleShack]

Well for those interested, the truck got worse last week taking up to 12-15 turn overs before firing, so I had to break down and take it in before i burnd out the starter or the fuel pump.

After I dropped it off, it acted up when they tried to start it to move it to the bay. Once it was on the bay they say it fired right up for 2 1/2 days with no issues. Finally on the 3rd day after the mechanic went home, the service advisor went to move the truck out side and it acted up on him, so he left it where it was. The next day the mechanic thought it was a bad injector. They had to test each one by capping off something and doing it one injector at a time or something.

After all the testing is done and the dust has settled, turns out I supposedly had 2 bad injectors for $650 a piece plus labor. This puts a bite into my "Fun" budget for the summer.

The truck has 139,000 on it, any idea what causes bad injectors? Just trying to avoid that so it doesn't happen again.

Just an FYI for anyone else who might have this problem.

[311Hemi]

How often are you changing the fuel filter?

[Valv]

Filters are a good issue. I use Baldwin PF7977 5 microns, you can buy them online at certain sites.

Also the FASS system is a very good solution, even though it's a little expensive.

I replace mine at every oil change, it's cheap insurance compared to the cost of new injectors.

Once in a while add a quart of 2 stroke TCW oil to a tank of fuel, it will help lubricating the pump and injectors, the new ULLS diesel does not have much lubricity anymore.

If you had a 2nd gen Dodge you can buy 6 brand new injectors for $ 350 total. Not the same with the 3rd gen, they are electronically controlled (just like the other 2 brands) and they cost a fortune anymore.

[MuleShack]

I just use the napa filters, not sure what microns they are, but I will look into the baldwins.

What is the Fass system you speak of. Not familiar with that acronym.

[Valv]

Napa Gold are 10microns, you can get them at Fleetfilter at 1/2 price.

Do a search for Fass, you'll get a lot of results.

[Powerstroke]

Main cause for failed injectors is dirty fuel getting to them. Another options to think of, I'm not sure on your Dodge, but on my Ford the injectors are operated by the high pressure oil pump and if you're pushing your oil change intervals then the dirtier and thicker oil puts a lot of stress on the injectors. This is very common on the FOrd's. Another reason the Ford's have injector failure is low fuel pressure the injector starves and is hammering against less fuel than it is expecting.

I know that doesn't directly apply, but hopefully someone who knows more about that Cummins can tell you if those apply.

As far as getting the flash updates, they can do many things. The factory comes up with lots of reasons to create new flashes. Some cure minor variations in engine functions such as emissions. This can have good and bad impacts which is why they come up with new flashes all the time. I would do some research online before you get the newest flash. If you don't care, I wouldn't get it.

[MuleShack]

Napa Gold are 10microns, you can get them at Fleetfilter at 1/2 price.

Do a search for Fass, you'll get a lot of results.

Sheeet, that site will save me a lot of mula...thanks.

Those Fass systems sound pretty beneficial in saving pump life as well as a double filtration. Which one would you recommend or how do you know which one of the 3 would work best for a user?

[MuleShack]

Main cause for failed injectors is dirty fuel getting to them.

and if you're pushing your oil change intervals

I put about 28,000 miles on a year and run the amsoil X-40 in the summer and 5-30 in the late fall and winter doing 2 changes a year. So each change gets roughly 14,000 miles and I change the oil filter out at about 5,000 miles. I have been changing the fuel filters when I change the oil, twice a year.

Just out of curiosity, being fuel seems to be a potential problem...when changing the fuel filters. Do you shut off the fuel valve and drain the fuel in the resevoir before removing and replacing filter or do you just unscrew the lid, pull out the old one and stick in the new one? I have been just pulling the old one out and putting in the new one, but thinking that may allow particles to settle directly into the line before the new filter goes on.

[Valv]

Main cause for failed injectors is dirty fuel getting to them. Another options to think of, I'm not sure on your Dodge, but on my Ford the injectors are operated by the high pressure oil pump and if you're pushing your oil change intervals then the dirtier and thicker oil puts a lot of stress on the injectors. This is very common on the FOrd's. Another reason the Ford's have injector failure is low fuel pressure the injector starves and is hammering against less fuel than it is expecting.

Excellent point. While the pump and injectors are slightly different than Ford the principle is similar,

I would go back and ask the dealer if the knew what the cause could have been and ask them if they did read the common rail pressure. I don't think you have much to worry about at this point.

[Powerstroke]

I know each brand has their gremlins and the 6.0L Ford have a couple that are well known. This is what I have so I try to stay on top of it. With a quality filter and quality oil you can push drain intervals to 10-15K miles, but not without getting an oil sample analyzed.

I know my truck was having injector issues and some slight misfiring but it was only cold related. After doing some other checking I was told to do change the oil and filter as well as the fuel filters. This cost me about $130 with Rotella T-6 synthetic, but my problems cleared up within a couple days of the change. I plan on doing another change at 5k miles and hopefully that will help me out.

Definitely check the fuel pressure. Its maintained by a spring or diaphragm and they can weaken over time. Its a fairly easy fix and will pay dividends if needed.

[311Hemi]

Fuel pressure would be good to check, and I assume they would check that?

With the 24v Cummins, the lift pumps are known to go out and when they do your injector pump follows. Not sure if that would then lead to bad injectors.

I have read of some that always put additives in their gas to make sure the injector pump gets proper lubrication. I do not do that myself at this point....knock on wood.