MS3 and LT1 Camaro

[Dookie454]

James,

221.004 with adding your 330ohm resistors (from 480ohm) helped allot, now it seems ok to 6480rpm then causes it to lose sync.
221.005 with no other changes causes loss of sync near 4000rpm.

Do you think pot adjustment would take care of the difference since you mentioned 221.005 working to 5200rpm?

[jsmcortina]

Please take a datalog and post it. (There's a little debug info in there.)

James

[jsmcortina]

Another thought on this.... you could bypass the "crank" tach circuit altogether. The V3.57 schematics show a value of 0.22u for C31 which, if correct, would be disturbing the low-res signal at high rpms.

Remove the jumpers from J1 and JP1 on the mainboard and then run a 1k resistor/jumper wire from J1 pin 6 (middle of board) to JP2 pin 2 (bottom right edge of board).

If you have access to a scope to observe the signals reaching the CPU at high rpms that would be very useful.

James

[Dookie454]

Another thought on this.... you could bypass the "crank" tach circuit altogether. The V3.57 schematics show a value of 0.22u for C31 which, if correct, would be disturbing the low-res signal at high rpms.

Remove the jumpers from J1 and JP1 on the mainboard and then run a 1k resistor/jumper wire from J1 pin 6 (middle of board) to JP2 pin 2 (bottom right edge of board).

If you have access to a scope to observe the signals reaching the CPU at high rpms that would be very useful.

James

Simply amazing! James your the man! Clean and smooth all the way up towards 11,000rpm! Beyond that it breaks up but im pretty sure I wont be anywhere near 11,000. I'll keep running it make sure it's solid but so far so good!

I connected 8 LED's directly to 4v using my 3rd channel on the power supply (gounds linked to each other) and Im getting sequential injection, however they are following the A-H pattern even though I have my firing order as A = 1, B = 8, C = 4, D = 3, E = 6, F = 5, G = 7, H = 2. Should these settings change the injector firing order?

[jsmcortina]

Glad to hear it is working, that's really great news - spread the word to other LT1 owners.

I connected 8 LED's directly to 4v using my 3rd channel on the power supply (gounds linked to each other) and Im getting sequential injection, however they are following the A-H pattern even though I have my firing order as A = 1, B = 8, C = 4, D = 3, E = 6, F = 5, G = 7, H = 2. Should these settings change the injector firing order?

That is how it is designed to work. The outputs always fire in sequence - you have to put the firing order into the loom.

The firing order entry is used for trim, EGO and the like to know which output corresponds to which cylinder.

James

[Dookie454]

Well I got it running with the sequential install... and it loses sync when idling, sometimes so bad it stalls. "Error 65 CAS360 running". I think it's much worse around idle than it is at higher revs but I didnt want to rev it too much.

The Opti is a MSD Pro-Billet but worked fine with the stock PCM, and worked fine with the low res signal wire shared with my stock PCM (no sync loss during the first 20 miles in batch fire mode). My 330ohm resistors are at the end of the 12ft wires for the MS3 and about 4-5ft down the path of the stock Opti harness right at the connector for the stock PCM. The PCM is still sharing the opti signal for spark control.

I connected the bench opti and motor and things look great (without motor running), the spark was sparking, fuel pump running, but the distributor wasn't spinning and no plug wires are near any MS3 wires since LT1's have them down low. The only difference is the engine isnt running, alternator isnt charging, and the injectors arent spraying fuel (fuse pulled). Also the PT4 wire holding the high res signal isnt shielded The MSD box was making it's noise but it didnt lose sync once while testing without engine running.

All MS3 grounds feed back to the main alternator mount bolt and allot of the MS3 wires are near the alternator.

Do you think this is related to the 11,000rpm loss of sync or do you think it's noise from alternator, injector wires, other? datalog attached.

[jsmcortina]

While bench testing I've had my setup down to 6rpm without sync-loss. I'm pretty sure your problem is due to noise getting in.

Are you using the first or second code? Any difference between the two?

You might need to shield those wires and/or add some low value capacitors (e.g. 1n) to ground at the input to the Megasquirt.

James

[Dookie454]

While bench testing I've had my setup down to 6rpm without sync-loss. I'm pretty sure your problem is due to noise getting in.

Are you using the first or second code? Any difference between the two?

You might need to shield those wires and/or add some low value capacitors (e.g. 1n) to ground at the input to the Megasquirt.

James

I ran v.004with a 1nF cap on the MS3X board on pin 31 PT4 unshielded high res wire to ground (p1M1 - was ground I believe), and no improvement.
I disconnected the alternator and no improvement, then I noticed the sync loss was also happening during crank.
I added a smaller coax cable from wire on pin 31 about 2" out of the MS3X box to the PCM after the resistor on the high res OPTI wire, and put the ground to the chassis ground near the PCM: No improvement.
I tested v.004 and v.005 and I think .004 may be a bit better of the two, though I didnt run .005 I just cranked it since the sync problems are apparent while cranking.
I adjusted the pots a bit, not improvement.
Now Im wondering if it's a difference in the MSD Billet Opti, could the sensor be slightly different?
"...new pickup assembly and distributor cap... Different from OEM, MSD's pickup is an advanced optical encoder, which is stable during extreme RPM." http://www.jegs.com/i/MSD/121/83811/10002/-1
I might order one, test it on the bench then return when done to compare to OEM bench unit. What do you think?

Crank looks like a good test to me since voltage is registering around 10.3v. Attached is a log.

[Dookie454]

This is a pic the MSD Billet Opti mentioned above, it has a different sensor than OEM.

[jsmcortina]

I don't think there's any reason to change your CAS.

Given that the code is working ok from 6rpm on my setup to 11,000rpm on your bench setup, I would conclude that the code is ok - provided it has a good signal.

Presently the composite logger will not record a true signal for Optispark, Nissan CASes or the flywheel tri-tach modes. I've idea in hand to allow it to log Nissan and Opti. Having that log from your car install should clarify what is going wrong with the signal between the Opti and the processor.

James

[Dookie454]

But, my bench opti plugged into the car harness as it sits works fine, so the only difference is the MSD Installed Opti and the fact that the car is cranking, somehow causing problems.

I only plan to plug the new MSD Opti into the car harness and spin it and make sure it reads ok, if it does not read properly then I know it's something with the new MSD Opti. If it reads OK then I have to wonder if my installed OPTI is bad, or something else is going on.

It might cost me shipping expense, but that's about it though I ordered it late and may not get it until Monday.

[jsmcortina]

But, my bench opti plugged into the car harness as it sits works fine, so the only difference is the MSD Installed Opti and the fact that the car is cranking, somehow causing problems.

Noise from the starter motor is a possibility.

Shame the opti is such a pig to swap.

James

[Dookie454]

Yea the opti is buried, and on top of that I have a supercharger and brackets that have to come off to get to it. But.. once everything is off I can switch opti's in minutes and start it without putting everything back on.
In a way I'm hoping the new opti doesn't work either (consistent with my installed opti), at least this way we know the problem and I don't have to switch opti's.

I was thinking starter could do something but then I remember it cuts out when running, so really I'm assuming crank sync loss is the same problem as running sync loss... I prob shouldn't do that huh.

Btw, I never installed the second 1nF cap on the existing shielded low res wire than ran batch fire ok, u think this is a problem?

[jsmcortina]

Btw, I never installed the second 1nF cap on the existing shielded low res wire than ran batch fire ok, u think this is a problem?

We are both running blind here.

When I've written some code that can take a composite log of the Optispark while cranking or running I email you - hopefully then we'll get some insight into what the code is seeing and why it is losing sync.

James

[Dookie454]

James, hopefully you can view this link: http://www.youtube.com/watch?v=q-UnuDu9H0I

This is how good your .004 code "as is" with a stock GM Opti really is. Rock solid. I've had it down to 25rpm and as high as 11,000rpm. Good stuff. I'm convinced the MSD opti is putting out something slightly different based on the huge difference between these two opti's, even though the OEM unit is not being turned by the cam/starter, you can hear how noisy the seat motor is.

[shortbus]

during_install.jpeg

You guys are making excellent headway on the optispark front. James is a genius and I know he can make it work.

For me I went down the cam wheel and crank wheel road.

I worked on it off and on since the last race weekend. The car is on the way back together now. After it is all buttoned up I need to reroute some oil cooler lines and then I will work on the harness.

I said I would post some pics, so here they are.

[Dookie454]

James, I tried your new 0.007 code, using my OEM opti it looks like it may spin slightly higher than the 0.004, to about 13,000 then looses sync. .004 may have spun to 11,000-12,000 where sync loss started to occur. Also, all versions seem to work very good down to only a few RPM.

However the new MSD OPTI does not register RPM at all in Tunerstudio using either .004 or .007, haven't tried .005, but the stock PCM is registering RPM showing on the car cluster.

My installed engine MSD Opti still looses sync pretty bad on both 0.004 and 0.007.

I find it interesting that the new MSD doesnt register at all. At least now we know the problem! The encoder wheel is physically larger diameter in the MSD version, would that throw things off? Not sure if there's more slots.

Composite logger files attached using all three opti's on .007 code. (including the working OEM opti for comparison).

[jsmcortina]

The phasing of the hi-res teeth to the low-res teeth is different. On the OEM opti the low-res edge falls smack in the middle of the hi-res (as seen at the CPU) while on the MSD Optis the edges are almost co-incident. How can that be ??

I'll send you another code where you can flip the hi-res capture edge through TunerStudio - look on the Ignition options page.

James

[Dookie454]

If I were to overlay the MSD and OEM disks I would expect them to look the same, however MSD opti encoder optics for hi and low res looks like they are spaced apart about 1" whereas the stock opti encoder optics are stacked on top if each other, at least it appears this way but I wouldn't think that would cause a difference since the high res slots are even and continuous.

The stock PCM must have more than one configuration built in? I wouldn't think the stock PCM would not work with that signal if it is much different than OEM.

I have played with the falling/rising edge a bit when running batch fire off the low res signal in 1.004 tunerstudio since I had to occasionally switch from one to the other occasionally to keep the RPM reading properly, i wasn't sure if that was a bug or where it was deciding to start reading the low res signal.

[Dookie454]

I've got some strange results.. the two MSD opti's are somehow different.

New MSD Opti spinning with drill:
- Falling Edge/Inverted: Normal rotation it registers cranking only, no RPM
- Falling Edge/Inverted: Reverse rotation it reads OK, no sync loss up to 3500rpm (don’t have it on my elec motor) and reads very low rpm. This seems like it would work but it was spinning the wrong direction, and this setting registers no RPM on the car MSD Opti
- Rising Edge/Normal: Nothing registers in either rotation direction
- Rising Edge/Inverted: 1300rpm minimum rpm, below this nothing is read. (I don’t remember what rotation)


MSD Opti Installed On Car by cranking/running (normal rotation only)
- Falling Edge/inverted: nothing
- Falling Edge/normal: Nothing
- Rising Edge/Normal: It ran but had sync loss at crank and running, crank sync loss seemed better than the 0.004 and 0.007 versions
- Rising Edge/inverted: same, no real difference