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False Spark Knock

Posted: Sun Jun 29, 2014 5:44 am
by maverickh1l
I have been having this issue since I got my 3100 running last year. Right now I'm stuck. I can't do much in the way of further tuning without getting this resolved. I need to get my spark advance set and my VE table leaner, but I can't do that with this issue present.

GM 3100 V6, approximately 11.4:1 CR. Distributorless ignition. Can't afford to blow the heads off as it's my only car.

My issue is that my MSII V3.0, B&G 2.92 board is seeing false spark knock at all times the engine is running. The engine side of the system is set up and works properly (already tested it as according to factory service manual). The MS is even seeing false knock with the knock module output wire completely disconnected from it (and right now, as it has been for a while, the knock sensor isn't even plugged in but the module wire is connected to the MS. Yes, I am running an MS to GM 165 adapter board and the one zener diode and resistor are already in place. I can't for the life of me think of what the problem is. Anyone? I'm currently running too rich and not enough spark advance and am really close in the tune but can't go any further without being able to read the knock sensor.

This is the same tune file I posted a couple of weeks ago and haven't gotten any response on for the tuning... I'm having issues with the other laptop not wanting to connect to the internet at the moment or I would post a current MSQ right now (didn't get a datalog yesterday like an confused person :? ). The log posted should still show the issue.

Re: False Spark Knock

Posted: Mon Jun 30, 2014 3:15 pm
by maverickh1l
As an update, I went through the log last night and noticed that the knock volts seem to rise and fall with the TPS and MAP voltages almost exactly, almost like I'm getting a cross feed between them. Knock sensor in the engine block is currently unplugged and has been for I don't know how long (and yes, I know it works as it worked with the 1227730 I ran for a while until I discovered a major fault in the ignition wiring in the harness). It also seems that knock retard degrees stays 0 even though the Tuner Studio gauge reports otherwise.

Re: False Spark Knock

Posted: Tue Jul 01, 2014 8:03 am
by Matt Cramer
What is the voltage output on the module?

Re: False Spark Knock

Posted: Sun Jul 06, 2014 11:38 am
by maverickh1l
I believe when I tested it the voltage signal coming into the MS was 10.32V...

Again, the engine side isn't the problem. I'm seeing false knock even with the module completely disconnected from the MS (as in wire not in the connector and just hanging there). That was the last thing I checked before deciding to just live with it at the time, which now I can't.

I'll have to get a datalog of this but right now I'm working on the interior of the car and have the dash completely removed.

Re: False Spark Knock

Posted: Tue Jul 08, 2014 7:07 am
by Matt Cramer
With the module disconnected, it will see zero volts and interpret that as knock.