DT466 No Crank No Start (Box Truck)

Hello all. Here I am giving this a shot after reading up on many threads and not being able to find a solution or what to check for next.

About 1 month ago, I noticed the starter a little heavy and sluggish. I still had the big ol OEM 42MT starter. After doing some research and checking up on Delco Remy website, I went ahead and got me a reman 39MT (Supposed to be better and longer lasting). So I had the 39MT starter ready at the shop to replace.

2 weeks ago the truck would crank very very slowly, I could not drive the truck to the shop as it would not start. Took the batteries to local parts store to get checked. Turned out the batteries were toast. So I got those brand new. Replaced starter and batteries. Went ahead and tried starting, only to get a click from one of the relays in the fusebox that is inside the cab.

This is where this terrible journey started. After all failed attempts, I removed reman'd starter (39MT) for testing outside and It all works fine. Put the starter back in. Checked all fuses with multimeter as well as relays. Even got me the LoadPRO multimeter leads, since it looks like it is one of the best things for finding solutions to electrical problems.

All relays click on both fuse boxes and no resistance on them. Already switched them around on fuse box and still nothing.

Did a load test with LoadPRO and it all checks. I have inspected the 3 fuses at batteries as well, and they are all good.

I did a voltage drop test on both poss at batteries and starter. Voltage stays constant at both multimeters. 12.31 give or take.

Park neutral switch seems to be ok, as I can see the line at dashboard move when I switch gears. The 3 connectors at IDM had oil leaking out when I unplugged to check for cleanliness. Also the connectors that come from the batteries had some oil dripping when I unplugged them to check for cleanliness.

I have no voltage on switch terminal that goes on starter. No voltage on OCP harness either. I really do not know what else to check. I have been looking around everywhere on forums and youtube with no luck. Some posts mention similar things, but then they stop posting which led me to creating my own thread.

I had an electrical tech inspect and he tells me my ECM is bad, as there is no ground on 85 pin at starter relay. He put ground to it with an external wire and truck cranks but does not start. This is as far as I have gotten.

Hope I am not the only one that has been through this. Thanks in advance for any help!

Manny

Truck info:
VIN - 1HTMMAAM86H160105
ENGINE - DT466
MODEL YEAR - 2004
MODEL - D210
ADV. BHP @ RPM - 210@2300
ENGINE FAMILY - DT466
LB-FT TORQU - 520 @ 1400
DISPLACEMENT - 466in3 7.6L
EMISSION FAMILY - 4NVXH0466AEA
LABEL NUMBER - 1842496C1
EMISSION CONTROL SYSTEMS - DI, TC, ECM, CAC, EGR, DOC
VALVE LASH COLD - .483mm (.019in) INT & EXH
CURB IDLE FUEL RATE @ ADV. POWER AND INFECTION TIMING ARE NON-ADJUSTABLE
TRANSMISION - ALLISON 2200 SHALLOW PAN

 

Thanks for the tip. I had gone through every single fuse and relay on this truck. Checking for resistance and such. They all checked fine.

Had a guy that used to work at freighliner and kenworth dealers. The issue was with the OCP temp sensor at the starter motor. He basically bridged the harness, bypassing the ocp plug and the truck is now starting normal.

I still do not understand how this happens, as I checked for voltage on that 2 wire harness that goes into the OCP plug at the starter motor. Had 0 voltage getting to it or the key switch at top of the 39MT IMS relay (which my 42MT starter motor did not have).

Still trying to figure out if this is safe to run without hurting the ECM. I called Delco Remy and they said bypassing the OCP sensor would damage the starter motor in the event of over cranking the engine.

Any help understanding this is appreciated.

I kinda had a feeling all along that the starter motor was the one giving the troubles, as it all started happening after I replaced the OEM 42MT with the reman 39MT.

Gonna try and get a new OCP sensor and switch up to see if it bring matters back to normal.