3176 blowing ecm fuse

[rmllarue91]

Hey hef i got a 345bl blowing ecm fuse haven't got back to machine in few days but it's still on my mind. The wire is a white 14 gauge #123 it's got a splice dropping to 18 gauge for dlc connector. Anyways down an dirty i cut wire at ecm before it branches off. Rigged up fused power source and she still blows fuse. Next thought was unhook engine connector from ecm and try again.... The screw is stripped so i unhooked few sensors and injector connector. Still blows fuse. So here's my question anyone ever see this before?
Obviously I got more testing but it's on my mind and can't get to it at least to Tuesday. So I'm making a game plan first thing will probably be try beating an extractor in Allen head bolt and unhooking Conn 2 then trying fused power once again and then probably unhooking both ecm conn. and just powering up ecm with grounds and powers and see if ecm is just plain shorted. But if ecm is shorted what's a good plan for testing possiblecauses of shorting? I've seen injectors short out but usually just burn out driver. I've seen few smoked ecms from welding or bad ground but they never made a direct short. I've been using smaller fuse than called for trying to preserve short lol. Let me know how you'd finish diagnoses Thanks s/n 4ss308 i got schematic

 

[Nige]

123-WH goes through three major harness connectors between the fuse holder supply side and the ECM.
Have you tried opening the following connectors (going from the fuse panel in the direction of the ECM) and see if the fuse still blows.?
1. CONN 44
2. CONN 11
3. CONN 3.

Actually if you have a Deutsch connector pin removal tool you could easily disconnect the 123-WH wire at each of the above-mentioned connectors and then reconnect the connector so all other circuits going through each one would be unaffected.

 

[rmllarue91]

123-WH goes through three major harness connectors between the fuse holder supply side and the ECM.
Have you tried opening the following connectors (going from the fuse panel in the direction of the ECM) and see if the fuse still blows.?
1. CONN 44
2. CONN 11
3. CONN 3.

Actually if you have a Deutsch connector pin removal tool you could easily disconnect the 123-WH wire at each of the above-mentioned connectors and then reconnect the connector so all other circuits going through each one would be unaffected.

I cheated and cut wire at ecm connector to rule out any harness issues

 

[Nige]

Let me get this right. With the wire cut at the ECM connector the fuse still blows when the key switch is energized.?

 

[rmllarue91]

Let me get this right. With the wire cut at the ECM connector the fuse still blows when the key switch is energized.?

No when I cut wire at ecm cab fuse does not blow. But it blows a 7.5 amp fused test hot wire i was using. 123 is not shorted. Short appears to be in ecm or an input out put of ecm.

 

[Nige]

My bad. I misunderstood your OP.
Then in that case the next step has to be to get both plugs off the engine control somehow, power Pin 6 and ground Pin 5.

 

[rmllarue91]

Ecm is fired. As for tracking down reason i didn't get there yet. It was pushing engine oil though engine harness to ecm connector. Is there anything common on these to push oil though harness?

 

[Nige]

It was pushing engine oil though engine harness to ecm connector. Is there anything common on these to push oil though harness?

With the location of the ECM wouldn't it be more likely to be flowing downhill with gravity rather than being "pushed"..? The braided protection of the main harness & branches isn't oil-tight like a hose would be.

 

[rmllarue91]

I could buy that hot oil gravity vibration.
I split ecm case and can't visually see short.... Should of used bigger fuse.....
What's the Chances that engine oil conducted enough amps across pins at ecm connector to short something in ecm out...

 

[Birken Vogt]

Well since wires enter valve covers and terminate on open metal terminals all over the place, covered in flying oil, I would assume it does not conduct electricity very well. But still does not belong inside an ECM.

 

[Nige]

What's the Chances that engine oil conducted enough amps across pins at ecm connector to short something in ecm out...

Unlikely I would have thought. Petroleum products are not known for being especially conductive.

Did the ECM smell burned when you opend it up.?

 

[Truck Shop]

Just food for thought-One major problem Detroit Series 60's have is oil making it's way down through injector/jake harness and shorting/killing
injector signals. But I have never heard of one causing a fuse issue. But I have found harness connections at the ECM soaked in oil. my 2 cents.

 

[Nige]

Just food for thought-One major problem Detroit Series 60's have is oil making it's way down through injector/jake harness and shorting/killing injector signals.

Is the power supply to the injectors on the Detroit somewhere around 90-120V like the Cat engines.? If it is I could easily see oil in the connectors causing problems with one or more injectors.

 

[Truck Shop]

Can't find my section on Detroit involving injector/ECM-Nige.

 

[JD955SC]

Ecm is fired. As for tracking down reason i didn't get there yet. It was pushing engine oil though engine harness to ecm connector. Is there anything common on these to push oil though harness?

Anything like an oil pressure or temp sending unit can wick oil up the harness. We’ve seen a few harnesses with oil pushed through them. Also DEF is notorious for wicking up harnesses on the newer machines.

 

[rmllarue91]

Update.... Got a used ecm install it after changing injector and external wiring harnesses.
After plugging ET IN It's off a 345bl series 2. WTF ? AGS806 SERIAL. MACHINE IM WORKING ON IS 4SS,308. ECM CONNECTOR 2 WIRED VERY DIFFERENT.

 

[Nige]

Have a look at the ECM Part Numbers for the two schematics. Should be right above the area your photos are showing. What are they.?

 

[Nige]

After looking closer, the Pin Numbers are arranged in a different order on the two schematics but most of them go into the same pins on the ECM connector.
Based on wire numbers & colours the only ones I can see that go to completely different Pin Numbers are:-
Coolant Temp - pin 14 vs pin 15. Same wire number
Intake Manifold Air Temp - pin 2 vs pin 9. same wire number.
Nothing on lower one for fuel pressure (Pin 14 A745-WH)
Top one has two Eng Spd/Timing wires on Pins 37 & 39 where lower one only has one on Pin 37. The wire on Pin 37 in both cases is 999-WH.

 

[Nige]

Update. Both engine controllers (for AGS & 4SS) are the same Part Number 115-3055.
I would bet the difference between the two will be the software flash file and there is no way to officially get passwords to re-rate the ECM because it will require an Interlock Code change. The 4SS software flash file is Interlock Code 37 and the AGS software is Interlock Code 51.

 

[rmllarue91]

We just ordered a new one had cat program this morning and it works fine. Weird parts is the machine it came out isn't a series two the motor was switched i guess.