Not reading dizzy signal...possible pcb problem?

[X64v]

I've been running MSnS-E ignition only on my l24 for two weeks now, everything worked great. This weekend I got the fuel system set up, and hooked everything up to run fuel and ignition. I started it up for the first time, and it idled okay, but I needed to adjust some stuff, so I shut it off, and when I started it back up, I was getting a real rough idle and the tach was bouncing a lot. After about 10 seconds of that, the engine just quit, and I could not get any rpm reading in Megatune while cranking. I'm running a pertronix ignitor (low to high) in the stock 240 dizzy (locked down of course), on a V3 pcb. I've installed all the coil driver and hall/optical sensor circuitry, and jumpered it to run a low to high hall circuit. As I said, it ran great for two weeks doing ignition only, but just a minute or two after I got it running fuel, it quit reading the dizzy's input. It's wired up correctly, and the connections and wiring have been quadruple checked, as well as the ignitor checked (it's working fine). I didn't change any of the spark settings in megatune when I set up the fuel stuff, so the last thing I can think of is a problem with the circuit board somewhere (though visually it looks as it did before, nothing burnt or melted or anything). Does anybody have any suggestions as to what circuits to check, or anything else it could possibly be?

[woldson]

maby try reloading all software/firmware?

[trwebb26]

You first need to check to make sure that the dizzy is wired correctly (low to high or high to low). Trust me - if it is wrong you'll be troubleshooting around the root cause for a LONG time.

http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#hallV33

 

What do you have set as the trigger angle?

How is the output to your ignition box wired?

Is spark output set to inverted?

Can you set a fixed spark (say 25 degrees) and turn the engine over? Is the timing accurate?

WHAT SPARK PLUG WIRES ARE YOU USING!!!??? (Please tell me Magnecor's)

 

It is very possible that you could have the trigger input wrong and still run fuel only. You can tweak enough variables in megasquirt to make it run. In other words - it really doesn't matter that you've had it running on fuel - spark is another HUGE set of headaches that require their own troubleshooting. Be patient and we'll get you up and running in no time.

[Matt Cramer]

While there's a Hall sensor in the Pertronix, you won't actually get to access it unless you cut the casing open. It's better to set this up to behave like you are using points; see this link for the details:

 

http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#points

[X64v]

It is very possible that you could have the trigger input wrong and still run fuel only. You can tweak enough variables in megasquirt to make it run. In other words - it really doesn't matter that you've had it running on fuel - spark is another HUGE set of headaches that require their own troubleshooting. Be patient and we'll get you up and running in no time.

 

Actually it's the other way around. I've had it running ignition for two weeks, with su's doing fuel. It was when I added the fuel duties that it quit reading the signal.

 

Trigger angle is set at 80*

The red wire on the ignitor has +12v power

The black wire on the ignitor is going into pin 24 (white ign wire on diyautotune's harness)

Pin 36 is connected to the coil negative terminal

Spark output is inverted

I cannot get any rpm reading in megatune (and therefore no spark signal out of megasquirt.

 

(And I'm runing NGK plug wires, which are 6 months old and work fine)

 

I'm going to reload the software onto the megasquirt board and redo all the settings to make sure none of that got miffed up.

[X64v]

While there's a Hall sensor in the Pertronix, you won't actually get to access it unless you cut the casing open. It's better to set this up to behave like you are using points; see this link for the details:

 

http://www.msextra.com/manuals/MS_Extra_Ignition_Hardware_Manual.htm#points

 

Ah, I see. I noticed that instead of high being +5v or +12v, I'm getting maybe a volt or two out of it. Is that what the condenser does in the points set up? (therefore needing to set it up as if for points?)

 

And I'm switching the jumpers on my board right now to try the points set up.

[X64v]

Nope, still no go. Any other suggestions?

 

EDIT: I wired in the circut for just triggering off the coil negative, but that did not work either. Should I attempt to replace R12, R13, C11, and U3 with new ones, or is there anything else it could possibly be?

[trwebb26]

Try disconnecting your alternator and see if anything changes. It may sound crazy - but there is a method to my madness.

[X64v]

Update

 

I installed the VR circut on the pcb and hooked that up to an '82 zx na vr dizzy. Now, when I spin the dizzy (either cranking the engine or by hand) the megasquirt completely shuts off (all gauges go reddish-pink in megatune) until I stop spinning it. All connections are good and the pots are adjusted fully counterclockwise. Any ideas?

[trwebb26]

sounds like resets to me.

 

does the reset counter at the bottom right hand side of the screen increase in value?

 

If you are like everyone else with this problem - Magnecor wires are the solution.

 

Try unplugging your alternator and see if things improve.

[X64v]

I also tested it by holding the vr dizzy in my hand and physically turning the rotor with my finger (therefore eliminating both the alternator and plug wires). But yes, it is like one continuous reset until the rotor stops turning.

[X64v]

GOT IT!!!!! I coulda swarn I had all the settings in megasquirt right, but sometime when I was going through the fuel settings, LED 18 got changed to warm up, when it needed to be IRQ trigger.

 

Thanks for the help though guys.