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Old 02-09-2014, 03:57 PM   #1
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DIC Question

So, it would seem that pin 44 on the ECU receives knocking signals from the DIC, and pin 17 and 18 receive ignition confirmation signals, corresponding, respectively, with cylinders 1&2 and 3&4. This means that if the ECU receives a V+signal through pin 18, and receives a signal through pin 44, AND the CPS indicates that 1&4 are at TDC, then cylinder #4 has just suffered a knock.
If there were a short in any of the wires, wouldn't that manifest as PAIRED knocks, as in 1&2 would sequentially knock?
If not, how would a short show itself in terms of operation/knock?

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-Cm
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Old 02-11-2014, 08:08 PM   #2
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No guesses even?
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Old 02-12-2014, 09:12 PM   #3
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What kind of signal is the ecu expecting? Straight voltage? A specific resistance?
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Old 02-13-2014, 11:48 AM   #4
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All it says in the documentation is that pin 44 receives a "signal" in the occurrence of knock as generated by the DIC. The DIC measures current across each plug by applying an 80v reference potential across the electrode. Once current reaches a certain level, the DIC decides this is knock and sends the "signal" to the ECU on pin 44. The ecu decides which cylinder is the culprit from the CPS, and from which of the pins 17 or 18, receive voltage from the DIC.
So:
Receives + voltage @ pin 17= combustion confirmation in 1 or 2
Receives + voltage @ pin 18=combustion confirmation in 3 or 4

Receives "signal" @ pin 44= knock, as decided internally in the DIC. So, DIC monitors currents, and if it is displeased, sends "something" to pin 44. Probably sinusoidal voltage if I were to guess.

Doesnt really matter I think. If there were a disturbance in the wire 44, then there would be an absence of knock, or a random smattering or knock across all cylinders (which was the case until I re-wrapped the abraded section of wire)
Fault with wires to either 17 or 18 would be misfire,no?
-Cm
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Old 02-15-2014, 01:04 PM   #5
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Would a tighter gap yield more or less knock signals?
-Cm
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