This is a big deal for me since I use the truck for work, & I need it to run...

2005 Dodge Ram 3500 4x4 (not the truck in my sig)

OK, in order, events that took place:

A few days ago the truck stumbled momentarily, set a code of 2146, belched a little smoke and then ran fine. No problem after that.

Today, I started my truck (warm) and was idling when my "check gauges" light came on. The volt gauge was sitting on 8. This did not make sense to me since the truck was running fine. I figured if it was really 8 volts, then the fuel pump etc would not be working right. So I check with my multi-meter and the charging system is putting out 11.5 volts. Ok no problem, haul butt home (40 miles), to start pulling the alternator and have the wife PU a new alternator. All this time the gauge is still at 8. Pop hood and start to dissasemble. At this time I noticed a pretty good arc from the NEG batt cable when I pull it off. Hmmm, Ok I will check the charging system again before pulling it all apart. Start truck & check voltage. It is now jumping all around from 11.5 to 13.2 and back. So I pull NEG cable off again to see if the alternator is holding and maybe I have a bad batt. Truck runs for 5 seconds then stumbles and dies. Ok alternator bad. Check codes and find 2509 and 2502 now.

Switch out alternator and wrestle that stupid dang 10 foot long serp belt, get it all back together and start truck. All is well @ 14 volts, grids are cycling a bit, truck warms up and then the volt gauge went back to 8!! WTH?? Check with multi-meter again and voltage is jumping all over the place again, but now going from 11.5 to 14.6 very rapidly. Turn on headlights, all seems normal there, no flickering etc. Decide to try disconecting NEG batt cable again while running to isolate the alternator, and truck dies like before, so I think dang bad alt out of the box. Reconnect batteries, and now the truck will not start, I cannot pull codes, and the volt, fuel, oil, & temp gauges are not working. The RPM and MPH gauge jump a little when I cycle the key like normal, and all the warning lights test work, the odometer lights up as well as the gear indicator lights. What the heck is happening here? AlSO the low beams do not work (high beams do) and the lamp out indicator is chiming due to the low beams. I checked all the fuses and all look OK. Please help, if this truck dies, I am SCREWED!

Thanks in advance,

Danny

 

Just for fun, load test BOTH batteries, one could have a dead short. Isolate them, by unhooking all cables, then test them individually.

OCV should be around 12.5 to 12.8 volts per battery. Any less is a state of discharge. Figure 2.2 volts per cell, per battery in a 12 volt system.

Next, load test, 1/2 CCA for 15 seconds per battery, should not fall below 10.6 volts in that time, if they do, charge at a medium setting for 15 minutes, then load test again.

Check your EPS, or CPS, whichever it is called these days, Engine Position Sensor, being the generic term, or Cam Position Sensor, being brand specific. There is a chance it could be failing.

Check Grounds for high resistance, broken or frayed cables. This can cause nightmares.

On these trucks, like the older ones, the votage is regulated through the PCM if I remember right. Last ditch effort is to see if that is the problem.

Good luck

 

Never, but never disconnect the batteries with the engine running!

It is likely you corrupted the fuel control computer, the ECM and the PCM with that little stunt.

You will be chasing your tail until you can get the truck into a shop with good diagnostic equipment capable of reading all the OEM codes.

As far as the original problem with unstable or low alternator output, without a complete scan of the trouble codes, including all the companion codes, before screwing around with the electrical system you are wasting your time trying to guess your way to a solution on any Dodge made after 2002.

 

Make sure you read THIS post thoroughly!

 

Why could you have not told me this BEFORE I did that???

Just kidding, OK, there is a large 20A draw coming off somwhere. I checked the fuses and grids, but can seem to find it. I just hauled to the dealer and they are going to do a diagnostic. Supposed to be under $100 for this, so I will post up what they find.

Thank you for your replies.

Danny

 

Dealer says the scanner will not communicate with the truck. They "think" the ECM is fried but no gurantees. New ECM is $2300 including the flash. Any other ideas to double check? Everything the the truck workes electrically except a no start (cranks over OK), no fuel pump & no grid heaters. It will start with ether though.

Thanks!!!!

Danny

EDIT: ADDITIONAL INFO

I tested the "C"-code function and the instrument goes through it's test and all gauges move etc. There are no C codes. Just AA 00 then 00 00. The hours come up as 4007 hrs. So if this helps narrow it down.

 

i wouldnt recommend using ether to start a diesel... ether will ignite faster then diesel fuel will so it will detonate in the cylinder (the cylinder will fire before the piston reaches top dead center) which could cause problems. just a little bit might not hurt it, but its something i never wanted to find out. i could be wrong here and if so im sure i will be corrected but thats just my .02

on another note, do you know anyone with the same year truck whos ecm you could swap out just to see if that narrows it down.. the only issue i see with that though is if something fried your ecm then it will fry this ecm as well.. basically its 50/50/50 it will fix it or not if it does it will fry that ecm or it wont... just food for thought sorry for a long post

 

I second the caution about using ether. It drives the top compression ring down into the cylinder wall in a twist, and knocks the outside upper edge off the ring. It does not take much to damage a modern diesel with the high ring piston design needed for emission standards.

It is pretty easy to create ether dependency on any of the newer diesels. Once that top ring edge is shot, they only start on ether because they will not build high enough compression to cold start. Not a good solution!

 

I understand the ether concerns, but the dealer did that originally. So we'll see. I doub't any harm was done with just a short burst or two... The most damage that occured is when they were towing it out of the bay, the service manager did not stop and ran my truck into their "shop"truck breaking my airdam under the bumper!

I found a ECM online from a place that rebuilds them for around $700 exchange. They offer a lifetime warranty as well. I just want to make sure also IT IS THE ECM that communicates with the Starscan scanner? Also when I was removing it from the side of the engine, I noticed the bigger of two plugs may have been loose. I wonder if this was some of the problem from the start and with me screwing with the Alt/batteries, It just finished it off. I was able to manually activate the lift pump and the grid heaters, and checked the voltage at the "switched" terminal of the relay that the ECM activates and it was only 6 volts.

Another question I have, and I will search the general forum, is when the ECM is removed, the instrument cluster still shows the mileage. I thought this was all stored in the ECM. Is there another module that keeps this recorded?

Thanks again for the replies and the concerns!

 

After dealing with a very poor customer service at a place that specializes in re-manned ECM's, I finaly broke down and purchased one from a different Dodge dealer (saved $800 at least). When replacing the ECM and re-flashing it, we had to un-plug the ABS module then plug it back in. This was due to a VIN mismatch according to the DRB tool. While we were in there I had them do a tire size recalibration as well as activate my DRL's. I did forget however to have them enable the 4th gear lockout. Anway, thanks for all the replies, and I can go back to work now!