Matt Cramer

I've seen Megasquirt used with 12-1 wheels before without issue. Cranking timing will not be quite as precise, but there's very little practical difference compared to a 36-1 or 60-2 at those engine speeds. If you had a motorcycle with three times that redline, I'd definitely go with a 12-1.

#2 is supposed to be a ground. If you're using our harness, it is the outer shield on the IGN wire. Check to be sure this is not shorted to a 12 volt source.

I wonder if that was Bill Lucas you got it from? Bruce himself has a couple engines running on it.

If it still gets RPM on the Stim, it's likely to be a wiring issue. Missing pull up, maybe?

You'll need to get the RPM input working. Nothing else will work until that happens. Can you see an RPM signal on a Stimulator?

Just depends on what sort of maps you're used to - there are a couple other ECUs that use VE tables too.

It's just a 1K resistor from the wire going to pin 24 to a 12 volt wire.

With those settings, it is using O2 correction to adjust the fuel in closed loop, and the AMC feature updates the VE table in flash. Mostly because of the programmers have a preference for model based programming. Right now there isn't much that relies on the number being an actual VE, but some new code features being tested are going to use true volumetric efficiency for a couple of acceleration enrichment functions. A normal pulse width table is only the real pulse width at a single temperature anyway. It is possible to make a few changes to the code to use a pulsewidth table, but so far we haven't seen either anyone attempt to make this mod to the firmware or come anywhere close to convincing the programmers there is any advantage to a pulse width table.

We can set one up for you if you like... though we'd probably start with a V3.57 board and not a V3.0, so we could have the extra I/O connector.

Does this one have a MapDaddy or other real time barometric pressure sensor installed? If not, turn the barometric correction off. The barometric readings in the log look rather weird.

If you're using six in wasted spark, you can grab a couple of connections right off the board for them. Use PAD1 for spark output A, PAD3 for spark output B, and PAD2 for spark output C. Don't set the spark output to inverted for these.

I'll need to wait for the data log, but will take a look at the two files once the log is up.

Are you seeing RPM in MegaTune when you crank it?

There is no power-on light on the MS. The lights respond to things like RPM and temperature and are frequently off when the engine is not running.

The lights only respond to things like RPM so they may be off. If the ECU is communicating, don't worry about how the lights are.

Could you post a data log of this happening, with your MSQ file?

Could be a processor reset, could be a communications dropout, could be a time you hit the space bar while logging. The first two will be labeled MARK (some number) RESET, while the last kind is marked MARK (some number) MANUAL when the cursor is over it.

A short spike in the RPM can happen when you turn the power on. But does it stay there if you leave it on for a minute?

V3.0 and later boards have the ability to drive low impedance injectors without resistors - whether it's an MS1 or 2.

Com 3 doesn't look like it is a real port - the "S" response usually indicates it's some sort of diagnostic port that echos back every character sent. Check in the Device Manager and see if you can find the USB adapter. You may need to reload its driver.

That's correct.

You could check to see if you're getting a signal at the J1 jumper, using a LED tester. We'd probably pull out the oscilloscope at this stage, but I figure those are rarer out there than Stimulators.

Hard to say without my having checked it directly. How's the MS work on a Stim?

Well, I was just wondering if you were controlling the timing or not. Depending on how you have the board jumpered, it can sometimes have 5 volts at tach select until it sees a pulse. You could remove D1 or D2 and use it in that slot though.

Is the distributor timing locked out? Also, could you please post a copy of your MSQ file? I'd like to check the settings.