hawk-aggie
Member
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- 18
- Location
- College Station, Texas
NOTE: I'm going to be using the term "smart" box in referring to the EESS. Don't get twisted about semantics.
Our 1994 M1097 that I'm working on has an electrical issue. Engine is 6.5L, transmission is 3-speed, “smart” box is Natron, new starter, new batteries, new glow plugs, new glow plug controller, professionally rebuilt fuel injector pump, and auxiliary grounding harness.
I have disconnected many wires and cables - one at a time - to try to isolate the problem. The only thing I haven't done is disconnect any of the wires/cables on the 200A alternator or the voltage regulator. I have also been pouring over the wiring diagrams without positive result.
When I first connect the batteries, I get a significant spark at the ground post when the negative cable is connected. I've seen a small spark on most of our HMMWVs, but this is significantly different. It's not a big spark like you might see with a short. It's like something has its 'switch' permanently closed, causing a spark when the negative cable is connected.
I follow the normal starting process. I turn the ignition switch to run (I can hear the solenoid in the “smart” box clunk on). The wait light stays on about 8-12 seconds. Engine cranks strong. When it catches, the voltmeter is on the tick mark in the green zone – voltage checked with a multimeter indicates 28.4 volts. Oil pressure is just over 30 psi.
When I turn off the ignition, the engine does not shut down until I pull the lead to the fuel cutoff solenoid. When the ignition switch is turned off, the "smart" box relay does not go "clunk" as it should. The power on the fuel cutoff solenoid lead is still active and the "smart" box relay, and the voltmeter registers in the middle of the yellow band. When I then disconnect the battery, I hear the “smart” box relay clunk off, and the voltmeter needle drops to zero.
I don't believe this is a "smart" box issue. I have installed six (6) “smart” boxes so far during testing. I know now that "smart" box number 1 has a burnt/fried component (cause unknown). Boxes 2 - 5 are green label KDS. Issues inside them are unknown at this time. All had the same results as indicated above. The only difference between them is the wait time - from zip to quick flash to 8-10 seconds. The only reason the Natron is installed is that the engine fired right up without a lot of cranking.
My buddy and I are not on the same page. He thinks the issue is the smart box. I think there’s a wiring issue that keeps power to the smart box relay solenoid even after the ignition switch is turned off. We are open to ideas and consultation for fixing this truck.
Our 1994 M1097 that I'm working on has an electrical issue. Engine is 6.5L, transmission is 3-speed, “smart” box is Natron, new starter, new batteries, new glow plugs, new glow plug controller, professionally rebuilt fuel injector pump, and auxiliary grounding harness.
I have disconnected many wires and cables - one at a time - to try to isolate the problem. The only thing I haven't done is disconnect any of the wires/cables on the 200A alternator or the voltage regulator. I have also been pouring over the wiring diagrams without positive result.
When I first connect the batteries, I get a significant spark at the ground post when the negative cable is connected. I've seen a small spark on most of our HMMWVs, but this is significantly different. It's not a big spark like you might see with a short. It's like something has its 'switch' permanently closed, causing a spark when the negative cable is connected.
I follow the normal starting process. I turn the ignition switch to run (I can hear the solenoid in the “smart” box clunk on). The wait light stays on about 8-12 seconds. Engine cranks strong. When it catches, the voltmeter is on the tick mark in the green zone – voltage checked with a multimeter indicates 28.4 volts. Oil pressure is just over 30 psi.
When I turn off the ignition, the engine does not shut down until I pull the lead to the fuel cutoff solenoid. When the ignition switch is turned off, the "smart" box relay does not go "clunk" as it should. The power on the fuel cutoff solenoid lead is still active and the "smart" box relay, and the voltmeter registers in the middle of the yellow band. When I then disconnect the battery, I hear the “smart” box relay clunk off, and the voltmeter needle drops to zero.
I don't believe this is a "smart" box issue. I have installed six (6) “smart” boxes so far during testing. I know now that "smart" box number 1 has a burnt/fried component (cause unknown). Boxes 2 - 5 are green label KDS. Issues inside them are unknown at this time. All had the same results as indicated above. The only difference between them is the wait time - from zip to quick flash to 8-10 seconds. The only reason the Natron is installed is that the engine fired right up without a lot of cranking.
My buddy and I are not on the same page. He thinks the issue is the smart box. I think there’s a wiring issue that keeps power to the smart box relay solenoid even after the ignition switch is turned off. We are open to ideas and consultation for fixing this truck.
