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Hobinator1

ECM Auto or Manual does it matter?

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Hello all,

 I am fairly new to this sight but see that there are many very knowledgeable people here. I have a 1999 2500 that I have swapped from the 47re to Nv4500 with southbend dual disc clutch, new VP, quadzilla tuner, airdog raptor 4g lift pump. Now I have a bad ECM. I am wondering if when having my new ecm programmed I should request automatic settings since my truck is originally an automatic or if I should have it programmed with the Manual trans settings? Will having the manual ECM negatively affect the original automatic PCM? Any help is greatly appreciated!

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Im assuming it was working fine before the ECM went out I would imagine just get another one just like you had. Im making an educated guess here but I would think if you were to change the ECM to something the truck never had and not the PCM at the same time there would be some compatibility issues. The next problem is that to my knowledge all  PCMs are VIN programmed so it may not even be possible to get a new manual PCM to work with an automatic VIN. Ive personally used autoecmstore.com for replacements in the shop and although i havent had anything like this come up at a dealership they may be able to provide some insight. I will admit that I have a very limited knowledge of PCM/ECM programming but I will be learning alot more when i get my buggy going Im using a Megasquirt3 to tune a Honda V6 that Im running in a Baja Bug.

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To troubleshoot my brothers '01.5,  I swapped my '01.5 ECM into his.  

He has an automatic I have a manual.

His truck seemed no different with my ECM in it.

His in my truck was immediately noticeable.  His ECM does not have the stall control that my truck had.  So I couldn't just let the clutch out, like I can with my ECM.    Other than that I had no troubles back and forth.  But they are very close in manufacture date and I think the partnumber on one of the lines of the ECM was the same.  (but obviously had different programming)

mine is a base model truck and his was an SLT  but i don't think it was the highest level one with theft prevention and such.

 

Hag

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Thanks for the input! I went ahead and got it programmed to the original settings of the truck since it seems like there is a difference. I will update what happens when I get the new one in and tested. It is supposed to be here tomorrow. Thanks again!

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I'm not sure about the exact why my ECM started acting up. It's been very internment for a while now. I just assumed it was from age. The truck has right at 200k on it. I've read about alternators causing issues. I've changed/cleaned most of the grounds. The actual problem my ECM was having was it was hanging the 12 volt signal to pin 5 on the VP pump. That's the signal to turn the pump off, in turn not allowing it to start. I was also losing voltage to my lift pump as well as not having a signal to my wait to start light. Is there something else in particular I should look for?

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11 minutes ago, Hobinator1 said:

The actual problem my ECM was having was it was hanging the 12 volt signal to pin 5 on the VP pump. That's the signal to turn the pump off, in turn not allowing it to start. I was also losing voltage to my lift pump as well as not having a signal to my wait to start light. Is there something else in particular I should look for?

 

In other words, the ECM did NOT boot up at all. As long as the Wait To Start light never comes on the software never booted so it will not start. Our ECM's boot up like a normal PC. It's got a BIOS (Basic Input Output System) that tells the storage EPROM to load the software up and then the first instruction is to light the Wait To Start light and check for grid heaters needed or not. If you never get this VP44 will never power up. 

 

Typical killer is excessive AC noise from the alternator. Most people do some wild ideas attempting to mask the problem but never fix the problem which is fried alternator diodes. Hence why we sell the diodes here on the site for repairing the alternator. Then Dodge screwed the pooch on the electrical as @W-T will point out. 

 

 

 

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Mopar1973man, thanks for sharing that amazing thread! That was so nicely put together! I hope I didn't buy an ECM just because I have a crappy ground in that conjunction of a ground wire cluster that Chrysler did there. OMG! My ECM is actually working now after 2 weeks of a no start condition. It's been a couple times that it just randomly shut down driving down the road. I checked for voltage to my ECM and it checked out even when it wasn't booting up like you mentioned. I've never gotten a single code either. The thing that made me decide to go ahead with the ECM was the fact that during diagnosis I cut the key off, then fuel psi stuck on for like 10 seconds, I heard the ECM click and fuel psi dropped. That was after the earlier symptoms I listed.

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I've got a simple version of that same article...

 

4 minutes ago, Hobinator1 said:

I checked for voltage to my ECM and it checked out even when it wasn't booting up like you mentioned. I've never gotten a single code either.

Kind of hard to record an error code when the operating system isn't even booted up...

 

6 minutes ago, Hobinator1 said:

The thing that made me decide to go ahead with the ECM was the fact that during diagnosis I cut the key off, then fuel psi stuck on for like 10 seconds

Normal. The lift pump will run on after the key is switched off. It's possible to have lift pump run 10 seconds afterward. The only time the lift pump is supposed to cut instantly is if you stall the engine from say an accident if the tach signal drops to zero the ECM will instantly cut the lift pump. 

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1 hour ago, Mopar1973Man said:

I've got a simple version of that same article...

d of hard to record

1 hour ago, Mopar1973Man said:

 

Kind of hard to record an error code when the operating system isn't even booted up...

 

 

That makes great sense why I would not have any codes. Geez... Not sure why that never dawned on me. I am still wondering why my ECM would not boot up if it had the right voltage going to it? That still points back to an intermittent ECM issue, right? Or am I still missing a piece to this puzzle?

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26 minutes ago, Hobinator1 said:

I am still wondering why my ECM would not boot up if it had the right voltage going to it?

 

Because when AC noise is introduced to the ECM the AC ripple is like a hammer banging away at all the processors in the ECM. This AC ripple creates heat and the chips start to fail. Now you have an ECM with a random issue because when the ECM is cool its working fine for the most part but as heat (block and/or AC noise) is placed on the ECM it stresses the ECM till it fails. DC wise you are going to have all the power needed but AC wise your most likely over the limit.

 

Watch this video it explains a bunch... Then go back and read over W-T's article... As you'll see AC noise is not just a Cummins thing all vehicles can have the issue but they all exhibit the weird behavior in different ways.

 

 

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Thanks again for such great information! Looks like I'll definitely be doing the ground wire upgrade and testing my alternator for ac current to see what I'm putting out before I destroy another ECM. As you know, those things aren't cheap! Ironically, I replaced my alternator about 6 months ago for charging problems. I can't help but wonder if it had a diode issue out of the box helping this issue along... I'll update what I find. Thanks again! :thumbup2:

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On ‎9‎/‎15‎/‎2018 at 12:13 PM, Mopar1973Man said:

You need a meter capable of measuring mV AC and variable frequency. Like I'm using a Fluke 75.

Okay, so I got a meter that would read mV AC but I am not sure about variable frequency. It was one from home depot that I borrowed before buying it and the readings were different than above but fluctuated from 0 to 30 ish. I am thinking that was still related to the cheap meter and maybe the lack of variable frequency? Is the variable frequency the feature I am most likely missing?

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1 hour ago, Mopar1973Man said:

Basically you need to spend roughly 100 dollars for good meter that has 2V or 20mV setting on AC side. 

I need some help with this. I have an Innova, $30, the meter only has one setting for AC. The paper work says it auto adjusts. Whenever I take the reading on the alternator it reprents the reading as 0.010 or whatever. A couple years back I had an electrician on the job with his Fluke meter and his only had the one setting and he told it auto adjusts. His read the same way. Am I missing something?

Edited by dripley

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I also have an Innova. Paid around $40 for mine. #3760 I think but need to double check. It does the job well. I test both all acc. on as well as off and it changes values so I know it's not 'stuck'. I remember going through this before.

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Okay, I was able to get my hands on a very nice meter tonight and these were my readings. The first pic is my truck the second pic is my buddies truck. I thought my readings looked good but was wondering if my buddies was borderline? Thanks again for all the help!!

20180918_182110.jpg

20180918_182853.jpg

2 hours ago, dripley said:

I need some help with this. I have an Innova, $30, the meter only has one setting for AC. The paper work says it auto adjusts. Whenever I take the reading on the alternator it reprents the reading as 0.010 or whatever. A couple years back I had an electrician on the job with his Fluke meter and his only had the one setting and he told it auto adjusts. His read the same way. Am I missing something? 

Dripley, I tried two meters before the one pictured above with no luck at all. I'm not sure why but the cheaper meters just don't read the same.

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44mV AC is borderline. (50 mV random problems start - 100mV is a fail.)

 

26mV AC is normal. (20 to 30mV)

 

Now if you did the W-T ground mod it will drop even lower. Be warned do not do the ground mod to cover up bad diodes. Replace the diodes first or replace the alternator before doing the ground mod. 

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2 minutes ago, Mopar1973Man said:

Now if you did the W-T ground mod it will drop even lower. Be warned do not do the ground mod to cover up bad diodes. Replace the diodes first or replace the alternator before doing the ground mod.  

Great! I'm gonna do the ground mod now that I've verified my numbers are good. My buddie is gonna go ahead and grab a diode set from the sight here then we'll do his ground mod.

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28 minutes ago, Hobinator1 said:

Dripley, I tried two meters before the one pictured above with no luck at all. I'm not sure why but the cheaper meters just don't read the same.

I got cheap at home i know wont but Innova does and its not expensive by any means. The ground mod really works good. Mine went from 0.035 to 0.010.

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