MS3 V1->V3 Upgrade - No RPM Sync
 

Hi,

I had a working MS3 V1 in a piggyback configuration which I decided to bring up to date by buying the V3 daughterboard kit and expansion card. I was originally using a crank angle sensor retrofitted into my 2001 for tach input, but have since switched to the VR input circuit so that I can tap into the factory crank/cam sensors.

Since a lot of things changed from V1 to V3, it was a bit of an exploration of removing components, and uninstalling some mods (boost/launch control, cmp/ckp) which used to be required to make this work. I primarily used Frank's guide as a step in the right direction, but since I've already installed a lot of components, I didn't want to strip out things needlessly. I feel that I've either forgotten to remove or add something properly as I can't seem to get the RPMs synced up.

I uploaded pictures of the MS (sans expander & cpu) to imgur since I didn't want to have to make them small resolution to abide by the image guidelines of the forum:

Front
Back

I've uploaded my MSQ that I'm using as well. I attempted to take a composite log, but the file had no data.

Thanks for any clues in the right direction. Let me know if I can provide any more information.

As in, it won't start? Did you adjust the pots as was described on Frank's site?

Correct. No RPM so I figure the Megasquirt doesn't even know it should be doing anything.

Pots were adjusted as per the instructions, then fine tuned. I dialed in R56 until the upper leg of R54 read 2.75v, and the lower leg of R17 maxed out around 2.28v.

Edit: I also have R52 installed, which isn't in Frank's instructions (he says to use a 100k resistor in pin 1 and 3), and it's turned counterclockwise until it clicked.

expanderboard as well?

Yup. Not shown since it looks the same as any. The Crank/CAM wires are tapped into the boomslang as per Frank's instructions.

Just in case I read it wrong, I should mention I don't have pin 26 on the MS3X wired in since I understand it is just an output.

did you turn r52 back about 7 turns clockwise?

did you take a composite log to see what the input signals look like?

I turned R52 counterclockwise until it clicked.

I did try to take a composite log while cranking for a few seconds but no rows of actual data were generated (just the headers) in the CSV which it saved to.

you have to turn it back 7-8 turns clockwise now.

crank for at least 15-20 seconds when you composite log.

Sorry, I misread what you asked ("back clockwise", derp). I'll turn R52 7-8 turns clockwise and get a composite log with a longer crank.

Is there a point where I can measure voltage as I adjust R52 to make sure it's dialed in correctly?

and can probe between ground and VROUT/TSEL. IIRC it should be 2.5v. 7 turns should be all you need.

Spinning R52 doesn't appear to change the voltage at VROUT/TSEL.

Just as another test, I saw Matt Cramer suggest:

I did the above and measured VROUT/TSEL and got 0.15v with 12v applied to pin 24, and 4.21v with pin 24 grounded.

I'll spin R52 as you directed and try getting a composite.

No go on the composite log. I did two logs, one cranking for 20 seconds, and one for 15. Both files were empty.

I also checked for continuity from the DB37 to the crimp-on connectors which tap the boomslang. Checked out for both Crank (MAIN-24) and CAM (MS3X-32).

Fixed. Cam input in the MSQ was still JS10 instead of MS3X Cam In.

thatll do it

Well, it got me closer anyway. I'm able to generate data with the composite logger, but still no start. Does the output look odd? Not sure what an '01 is supposed to look like.

no crank signal.

did you change the input to the VR circuit and change the jumpers and tune the pots?

Which input are you referring to?

Jumpers - Tach Select is set to VRIN, and TSEL is set to VROUT..

I dialed in R56 until the upper leg of R54 read 2.75v, and the lower leg of R17 maxed out around 2.28v. I turned R52 counterclockwise until it clicked, then turned it back 7-8 turns clockwise.

Gonna start going over this.

correct. did you do that?