No tach signal

[mergatroyd]

Some of the documentation seems to imply that I can run a cam wheel only to trigger ignition.

I have a 48-2 toothed wheel on the cam (this is on a bike so adding a crank wheel is non-trivial). The missing teeth are consecutive.

I know I should be using a microsquirt, but I had this megasquirt (that I thought was an MS-II until last night) lying around. Current code base is 029q, using an RS-Autosport harness.

I've installed 3 of these things over the last 8 years (this will be my fourth), but each one was a different flavor, so I get confused.

[Matt Cramer]

Yes, this can be done in Generic Wheel mode.

[mergatroyd]

Sweet. Thanks, Matt!

[mergatroyd]

All right.

So the engine has a Bosch 0 261 210 CPS, which I believe to be a three wire hall effect sensor. It is magnetic, and has white, brown and black into connector pins 1, 2, and 3 respectively. 963 ohms across 1 and 2, more resistance when steel is present at the magnet. Wired 12v into 1, signal at 2, ground at 3.

MS1 was configured for opto in because the previous install was using a distributor pickup. No tach signal.

I swapped the opto in for VR in based on discussion here http://www.msextra.com/forums/viewtopic.php?f=4&t=45654. Still no tach signal.

Tooth logger and trigger logger show nothing except MAP bounces when cranking.

I've attached a picture of the board from both sides as this board was purchased in 2006 and I cannot find the documentation for why it was configured this way.

NCM_00542.jpg

NCM_00552.jpg

[mergatroyd]

Okay, tach signal found.

I had the wheel setting wrong in the software.

Now I get no signal at the coil.

Investigating direct drive vb921 settings/wiring.

[mergatroyd]

Okay.

I have fuel and spark.

No matter how I set the fixed advance or the cranking/idle fueling, it will not actually idle consistently. Sometimes it will idle for a 15-30 seconds, and it will fire while cranking.

.msq is attached, I assume I am missing something entirely obvious.

I have it set as a 2 cylinder in order to get enough sparks per revolution out of the cam wheel trigger.

Any help is appreciated.

[Matt Cramer]

You shouldn't have to set it to 2 cylinder. You will, however, need to set four separate trigger positions and, if running wasted spark, set dual dizzy mode. As it is, this is only going to spark twice in a cam revolution.

[mergatroyd]

As it is a single cylinder beastie, I only need it to run one spark per cam revolution. It runs now, and idles (mostly) when warm.

Still running fixed advance.

However, I find that it sounds like MS is reading this at half RPM... the second trigger will make the RPM read properly? 4 cam triggers would allow me to put out an RPM signal that a 4 cylinder tach can read?

[Matt Cramer]

Sorry, somehow I thought this was a four cylinder! In this case, setting it as a twin will give you a spark every crank rotation - and for MS1/Extra, it will give you a bit of a more precise timing signal.

Can you post a data log of it running?

[mergatroyd]

Log file and most recent .msq attached.

I somehow corrupted the 029q load, and ended up loading the latest HiRes.

The VE table is currently acting as the rev limit due to the richness.

It is also visibly too rich down at the bottom end (black smoke out the exhaust and all).

110 octane.

[Matt Cramer]

I'm afraid the log only captured a couple seconds of cranking. Can you get a longer one?

[mergatroyd]

Sorry, grabbed the wrong log.

Attached is a better one with it warmed up. Timestamp is relevant to the previous attempt.

[Matt Cramer]

Ok, some notes:

1. I don't have any air/fuel readings in the log. If you can get a wideband connected to the MS, that will give a lot more tuning data.

2. Acceleration enrichment is triggering too easily. Try using TPSDot, raising the MAPdot threshold to 200, and adjust the TPSdot value as needed.

3. It doesn't take much throttle to send the MAP reading to almost fully pegged. I think this engine needs alpha-N fueling.

[mergatroyd]

1. Yeah, I know... but with leaded race gas... I have one laying around, but I don't know how much life it has left. The plugs are coming around to the right color.

2. Aha! Thanks for the help.

3. Yes... This is a forced induction engine with a positive displacement compressor, hence the early crossover into boost.