Computer Problem?
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Joined: Mar 2014
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From: Tyler, TX
Computer Problem?
I went to start my truck today and I let the glow plugs cycle, it only needed about 2 seconds since it had been run earlier. When I went to start the truck it acted like it had a dead battery and would not crank. The batteries have been weak but I turned the key off and turned it back on to run and the door alarm beeped quietly and in a weird pattern. The check engine light also flickered but would not come all the way on. I ended up trying to start it and cycling the glow plugs a few more times, and then it just started normally. Should I be worried about this? Maybe my IDM or PCM is going bad? It did rain last night so could there be water in one of the computers?
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From: Tyler, TX
I think the battery connections are OK, but the chip may be a problem. I just mounted it in the dash and may have pulled it out a bit. I'll check it tomorrow.
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From: Tyler, TX
I will run to Advance tomorrow to have them load tested. They were bought in 12/13 so they shouldn't be too bad, although I do plow which wears them out much faster.
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From: Tyler, TX
Got the batteries tested and the alternator too. All passed. Had about 650 CCA I think. Alt also passed but I dont know the number. I havent checked the chip yet. I cleaned the terminals but found that some of the connections were loose enough to wiggle off by hand. Would that make my truck not start like it did? I also want to mention my radio also reset when this happened.
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Senior User
Joined: Mar 2014
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From: Tyler, TX
yeah, I'm going to fix that today. I took off my plow pump and bracket yesterday which has not been unplugged for months and the batteries sounded much stronger. I'm thinking the plow may have been draining the batteries just a little too much. We'll see if this happens again.
Lead Driver
Joined: Oct 2003
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From: Madison, WI
The chip/PCM wouldn't have any effect on cranking. The starting circuit is completely electromechanical, with no tie to the engine control. You could bury a hatchet in the PCM and the engine would still crank with the key. You have a voltage/connection problem. 650 CCA sounds low for the batteries, but that would only cause the starter to crank slow, not a complete no-crank.
Logistics Pro
Joined: Oct 2008
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From: Avilla, IN
I agree with madpogue. I had batteries checked a few months ago because I thought they were getting weak. They tested good, but the tester said that one of the batteries had only 25% of its life left. (I'm not sure how they calculate that.) So I replaced it and it was obvious that was a weak battery.
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Also check your connections at the starter. We find those connections to be worst of all in the system.
EDIT: I re-read and see what you mean. With bad PCM the truck will still crank, just not fire up. Gotcha. At least when chip/PCM get fried, too.
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From: Tyler, TX
I agree with madpogue. I had batteries checked a few months ago because I thought they were getting weak. They tested good, but the tester said that one of the batteries had only 25% of its life left. (I'm not sure how they calculate that.) So I replaced it and it was obvious that was a weak battery.