MSefi.com read only forum (Jan.15,2018)

Great post, TheMonkey. I agree whole-heartedly.

When I took my Corvette to the chassis dyno expecting to just get a tune, I left with MUCH more. They had barely even used Megasquirt, but were able to find and diagnose several problems just based on having an extensive knowledge of EFI systems ...

That made a huge difference. Whereas the car was almost un-driveable before with all the dropouts and resultant ignition misses before, it was smooth and revved strongly. I did however still have a few counts +/- on the trigger, and at least a couple spots where it I had a tachcount reset because of ...

Edit - I had to delete my latest update, if I admitted my mistake, it would be embarrass theater.

Signal appears to be rock solid, commencing 46deg test drive. Chilly.

BTW, TheMonkey, where are you? I'm in Brooklyn Park.

I am in fact running a 60-2 wheel. My distances are actually quite consistent, 0.9, 0.9, 0.9, 2.9, 0.9, 0.9 to my measurements.

I'll make the transistor mod this afternoon and post back with results.

Low = 0V
High = 3.52V

Export from scope software to Excel and charted:



Is that tooth supposed to be there? If so, I reiterate that my signal looks clean to my eye. My ignition capture setting is Falling Edge, and I'm using VRout->TachSel.

I am experiencing this exact problem. At any RPM I am seeing tach dropouts. Trigger+- seems to count up more than it counts down, and I am seeing tachcount reset that the dropout/miss.

On my scope the VR signal looks very clean, as well as the signal into the CPU from the vr circuit. However ...

Still struggling.

Is it impossible to get advance if the sensor is positioned at the same # of delay teeth that corresponds to 0* BTDC.

ie: If the sensor is at 9 teeth, and 9 teeth is 0* BTDC, and delay teeth is set to 9, is that an incorrect setup?

Does my spark table look like enough advance, soon enough for a cast iron big block chevy? Compression should be around 10.5:1

For completeness I ran out and did one more test.

At trigger offsets:

4.00 = reading 1 deg BTDC according to my mark
0 = reading 5 deg BTDC
-4 = stumbled, died, wouldn't run

What am I doing wrong or looking at wrong?

I've got my BBC running and I've driven it a little but I'm really pretty lost on the timing.

I've got the 60-2 tooth lined up with the 9th tooth after the gap lined up to the VR sensor. In my MS wheel settings I have

Teeth: 60
Missing: 2
Skip: 15
Delay: 9

Trigger Offset: 4.00

Unless I don't ...

It really isn't that hard to tune your own VE table if you're already running and have the LC-1. Just drive it and use MegaLogViewer to analyze the logs after a drive, OR tune it live manually. You'll never get good results with someone else's VE table.

You've got the tools, just do it!

Agreed.

Thanks for the help gents.

http://www.youtube.com/watch?v=wekgrHqb6JQ

Solution: got a cheap non-digital timing light. Locked the timing in, and it fired right up. Still working on idle tuning. The GM IAC is giving me fits.

But NOW I'm having fun. Lesson: ASSUME NOTHING.

Correct. The stock ignition isn't exactly "known good" though as this is a brand new engine in a restored Corvette. Basically all new kit.

That's a pretty good idea, and I might have to give that a try tomorrow. Thats exactly where I'd like to get...tuning isn't an issue..but this initial start is ...

Made progress. Still no timing light (that works).

I'vWe were however able to get the engine to run for a few seconds with starter fluid and the fuel pump completely off. I've taken spark timing away from MS and am using a standard distributor. I can only assume that my timing is within the zone ...

I've gotten several backfires along the way, so I'm fairly confident that fuel is spraying. I'm not confident in the amounts though.

I'm also fairly confident in where the timing/offset is. I have the wheel at 9 teeth after missing at TDC, so I've set the delay to 7 which should set a base advance ...

8 44lb/hr injectors and about 45 psi. I'm adjusting the -40 cranking pulse width, setting it to between 11 and 13. 160 is at ~3

I'm trying to get the first start of my 468 BBC (~10.5 CR). I'm running a MS2 3.0 board with 2.886. 60-2 wheel, MSD6AL box for ignition, and 8 port injectors for fuel.

Stupidly, I don't have the latest MSQ that I was testing today. I'm running 12* of advance, and experimenting with 7.5-9.5ms ...

That's fantastic. I think I got it dialed in with a lot of trail/error, but this will still be invaluable. Thank you.

Hoping to start my engine tomorrow morning <Pray>.