09 ECM PROBLEM

[GWoody]

09 3500 AUTO, truck was running fine, stopped at a place and shut the truck off, came back out and started the truck, missing bad, scan tool confirms via injector kill and cylinder contribution test that 4,5, &6 are dead, but there isn't any injector codes. I assume that it has to be a bad injector solenoid causing the ecm to kill that circuit. Pull the wires off the injectors and they all ohm out the same. Replaced the valve cover gasket with the built in wiring harness for the injectors hoping that was it but no go. Pulled the plugs from the ecm cleaned and greased, plugged back in, still the same thing. I've never had a bad solenoid that the ecm didn't set a code. Everything mechanical seems fine, no excessive blow by, valves are adjusted correctly, cam is moving the rockers as they should be. Dealers scan tool doesn't show anymore than I can see with mine. Can't find any obvious wiring issues. Dealer tech and I are both thinking bad ecm. It's like one of the injector drivers died in the ecm and it can't report a code. Anyone have any ideas before I buy a refurbished ecm?
Thanks
Garry

 

[Missouri Mule]

Trying doing a search on here or the mag. Remember reading something to with electrical causing this. Did you see any wet spots. Check you oil to see is as risen

 

[GWoody]

Trying doing a search on here or the mag. Remember reading something to with electrical causing this. Did you see any wet spots. Check you oil to see is as risen

Oil level is fine, it's definitely a weird deal.

 

[Jim W]

How old are your batteries and are all of the connections clean and tight? Are the battery cables in good shape?

When my batteries were going bad on my truck the electronics started to act up as the voltage had drop off and was irregular in output. I had them load tested and one was bad and the other was borderline. I change out both batteries and everything was back to normal. Just wild though!

 

[GWoody]

How old are your batteries and are all of the connections clean and tight? Are the battery cables in good shape?

When my batteries were going bad on my truck the electronics started to act up as the voltage had drop off and was irregular in output. I had them load tested and one was bad and the other was borderline. I change out both batteries and everything was back to normal. Just wild though!

Batteries are 3 months old, they load test fine, we even disconnected the cables and connected ground to positive to drain the system. It's really a weird situation!!!!

 

[DonFitzwater]

Is there a way to test the circuitry of the ecm (the injector drivers)?

 

[GWoody]

Is there a way to test the circuitry of the ecm (the injector drivers)?

Not sure, dealer couldn't, maybe some type of bench test as far as resistance. Bit the bullet today and ordered a refurbished ecm that will be ready to go with the vin and programing loaded, 900 bucks. Hope it solves the problem!!!!!

 

[DonFitzwater]

Ok, well please post your findings after installing the new ECM.

 

[GWoody]

Update, new ECM didn't fix the problem. Pulled the injectors and had them tested, they said #5 was stuck closed and the rest were all bypassing too much fuel. Installed Bosch remans and truck is running again. It's just strange to me that injector kill test showed 4,5 & 6 not firing at all and this happened all of a sudden without any prior symptoms such as hard starts or low rail pressure codes. At least its fixed!!!!!

 

[sag2]

I guess I missed this one when it was first posted or I would have said again (for about the 20th time) Cummins ECU's don't fail.

 

[Missouri Mule]

Was it the injectors (as in where the fuel comes out or the electronic valves?)

 

[GWoody]

Solenoids were all functioning but injectors were shot.

 

[Axekicker]

I guess I missed this one when it was first posted or I would have said again (for about the 20th time) Cummins ECU's don't fail.

Question: I just posted a new TDR query today (1-9-20) asking for help with a problem with my ECM. My volt-meter is pegged (over 15volts) and the diesel shop that has my truck says it's a bad ECM. Alternator checks out OK....battery cables are all new....batteries are less than 1 year old but passenger side is bad due to over-charging.....drivers side battery is ok. They say it's the ECM but I'm skeptical. With your experience dealing with ECM/ECU's do you ever see units that work EXCEPT that they cause the alternator to increase voltage output to over 15 volts?

 

[Ozymandias]

YES absolutely you see often 15.2 or even a tad above on the CTD!
Over charged pass battery is always a bad connection wire. The ECM reads voltage from the driv side battery and sets charging voltage according to it.

 

[Axekicker]

YES absolutely you see often 15.2 or even a tad above on the CTD!
Over charged pass battery is always a bad connection wire. The ECM reads voltage from the driv side battery and sets charging voltage according to it.

That's what throws me....(most)everything is NEW under-hood. When the shop rebuilt the motor they put in all new battery cables....new ends...new clamps...new wiring to many components such as grid-heater wiring, new batteries etc. We've checked 'grounds' to motor...to frame...to cab...to batteries....all check 'good'.

The alternator checks out as 'good' on a bench-tester, but it's OEM...230,000 miles and 16 years old. ECM is OEM. I'm thinking the zener-diode in the ECM may be blown. I don't want to change-out the ECM so I'm thinking of a new alternator and installing an outboard voltage converter and just bypass the 'zener-diode' and see what happens.

 

[Ozymandias]

What are the command and return values that the ECM demands from the alternator? I hope your shop can read them.