DanTheMan

I was able to inspect the harness, and the brackets that bolt the harness to the block and to the frame have all been undone… I don’t think these ground the harness in anyway, as they spin freely around the harness and nothings connected to it. I will be working on reattaching everything properly once I figure out the issue. However, I did check every possible sensor, and on one sensor, I checked the 5v power (orange wire off of the IAT) to ground and it showed very consistent 5 volts. No fluctuations. It is my understanding that if I disconnect the APPS and it was the problem, it should revert to an idle, the voltage is consistent on the APPS as well. I may just completely remove the harness and just go through the whole thing entirely. I’m starting to lose patience with it lol

So I found an interesting problem… I heard a ticking sound, there is some arcing going on every few seconds. Now to find the culprit, I have no idea where to start. I’m assuming a wire rubbed raw and it is shorting against the block, or bracket. Any ideas where I should start? Specifically arcing by the harmonic balancer. Here is the link below to the YouTube video showing it. Considering it’s arcing every few seconds, I’m going to assume it’s coming off of the ECU and it’s self resetting, hence no blown fuses. YOUTUBE: ENGINE ARCING

Thank you, @Tractorman, I will check that out! Thanks for the diagram. The grounds have been all messed up on this truck so I’m hoping that I can find that connection point and that would be my problem. If it turns out the ECM is not delivering a consistent 5 V signal, can I put a 12 V to 5 V DC converter and supply power for all of the sensors? I am assuming that the three wires on the sensors, one is for ground, one is for reference voltage and the other is a signal going to the ECU, is returning voltage back to the ECU?

Guys I am at a loss. I HOPE someone can help me, this is frustrating. Bought my first 24v Cummins, it’s an 01, 3500 dually, and 5 speed nv4500. She fires up beautifully, idles normally. Then it gots warm and it idles up, stays around 1500rpm or so. The tachometer isn’t working, I tried replacing the camshaft position sensor and it didn’t fix the tachometer, maybe communication issue? Does the CPS have anything to do with idle? OBD2 computer says idling at 1500rpm. The APPS sensor was replaced, and voltage set. Stays below 0.50 volts, around .44-.48. According to the sensors live data reading, the voltage is all over the place for the other sensors too, the apps sensor is fluctuating bad, between 0 and 5v, and same with other sensors that are sensitive to voltage. I just redid the four battery terminals, grounds were in horrible shape, but the other ends going to the block and chassis are healthy. When I put a voltage meter on the APPS, I get very small fluctuations from .44 to .48, but the live data is freaking out. Things I’ve done: 1. Calibrate APPS with Multimeter on the orange/black wire coming, while setting voltage. 2. Checked alternator, it is consistent and I couldn’t find any alternating current in the system. (Unless I need an oscilloscope to see this?) 3. Checked all connections, the ECT sensor, the ground straps, everything. 4. Replaced IAT sensor 5. Replaced CPS..