Code to fix offset/delay teeth

[krisr]

Hey guys/Al/Bruce...

I'm going to be gearing up soon to re-fit the sequencer to my Pontiac engine in the coming weeks and I was reading that Al had stumbled upon the bug where the offset and delay teeth for those of us running chopper wheels had to be messed with quite a fair bit. I was curious if that code was ready to be released to beta or should I just try and find the "sweet spot" like Scott/TheMonkey did?

Hope all's well!

Kris

[grippo]

I was never able to reproduce Scott's problem, so I'm not certain about that. The problem with the new code is that it requires a change in the router processor as well as the main processor. So the only way the new code will work will be if you send me your sequencer for reprogramming.

[krisr]

Yeah I can organise to get it sent back to you - PM me with a postal address and i'll get the wheels turning. Does your gut tell you that this would be the last major flash that is needed or is there a way that I might be able to rig it up so I can flash it from over here down the track?

Did Bruce ever get his CBR engine running on it?

[grippo]

Kris,

I will send you my address. Yes I think it will be the last rev requiring a change in the router cpu. Anyone can burn the code with a bdm cable and the free version of Codewarrior, but the cable is about $100. And no Bruce still hasn't tried it on the CBR engine. But we are giving the board spin a final review this week and should have it ready to send out next week.

[robh]

I am using M-N code on my Microsquirt (1 130 tooth wheel with 1 reference tooth) and I am using the Sequencer 3.23 code to correct my tachout pulses (as addressed in this thread) http://www.microsquirt.com/viewtopic.php?f=89&t=22909.

I am having a similar issue with tach resets at certain RPM's as Scott and theMonkey have experienced. These tach resets move per my offset/delay teeth settings and with delay teeth @ 0 I have no tach reset (BUT get shrinking dwell at high RPM). So it sounds to me I may have the same issue. Unlike these guys, I don't have the sequencer (router board) so I should be able to upload new code... is there any way I could get a beta level code to try uploading to my uS to see if it fixes the resets? Or is there new sequencer code out there beyond 3.23 that addresses this?

Thanks!

[grippo]

The code is now up to 3.343 and I would be glad to send it to you - but in looking at the changes I don't see anything that would help with a microsquirt - the changes for the sequencer are mostly in parts of the code not used with just a microsquirt. So before I send you this, it would be better to post your msq and let me try it on the bench with both 3.230 and 3.343 code.

[robh]

Thank Al, attached is my .msq. This is on an 87 N/A 944 w/ VW COP's. The code is not at all fine tuned but it works...
Tonight I can try to get a datalog of the tach reset tonight then change the code to 0 offset and get another data log in the same rpm range if this is helpful.

Regards,
Rob

[grippo]

I have tested your msq and am able to see problems, but they may be related to my signal generator rather than real problems. If there is a software problem it is more likely related to the fact that you have an M-0 setup, which in principal is handled identically to an M-1 wheel, but it is possible there is a bug in that I may have missed a place where I check the modes. Unfortunately in the midst of testing last night there was a hurricane which took out power. I will resume testing this weekend, but meanwhile it wouldn't hurt to make the datalogs you propose.

[grippo]

OK I did a lot of testing on this changing all sorts of variables and testing 2.890 to 3.343 code. At first I thought it was this one and then that one causing the problem and eventually found that my signal generator will not reliably go past about 4000 rpm with a 130 tooth wheel. I know the processor and code are not the problem, because if I let things warm up or just wait for the right conditions it runs rock solid even at 5000 rpm. But regardless it may be reaching a limit where it will start dropping synch occasionally. I believe this limit to be around 5500 rpm, and I once told this to someone with a 130 tooth wheel who came back a few days later laughing and saying he had reached somewhere around 7500 rpm with it.

If the problem is only at high rpm (> 4 or 5000 rpm), then you may be reaching the limits of the processor or your VR signal may be changing at these rpms. When you get into the higher frequencies you start getting capacitance effects on the signal that can cause noise and phase shifting.

If it works fine at low rpms then the base code and configuration should be sound but the OUTPUTS can get screwed up at high rpm if you have trigger offset, delay teeth set non-optimally. But this should NOT cause dropped synchs (rpm = 0, trigger+/- counting up/down). It should just cause missed outputs because the dwell + spark advance time isn't optimally placed inside each double tach period. For example if your delay/ trigger offset is such that you need to spark 1 ms after you start tach1 period, then you aren't going to have time to get enough dwell; at the other end you may spark prematurely when tach3 occurs.

All I can do right now is wait for your data logs then look at that specific case, and try them and see if I get loss of synch. If the rpm is above 4000 rpm I will use a 60 tooth wheel, since there is no difference in logic between 60 and 130 teeth and I can scale the delay teeth to match your delay teeth.

[robh]

Here is a datalog from this morning showing tachloss at 3500RPM, 3300-3700 seems to be my only problem area. Recently I have been getting seldom tachloss in this area whereas before it was consistent everytime i was @ 3500 RPM. Moreover, with delay teeth at 0 and offset at -305 degrees I get zero tachlosses (not 100% about this on new code, need to test), I changed due to the shrinking dwell that you mentioned.

I have never experienced tach resets or tach loss above 4000 and have been as far as 6500 before.

Al, thanks for looking into this. I frequently drive the car (have 3000 miles on since changing to spark), this is just an annoyance to me, not a show stopper but it'd be great to solve. More-so out of my curiosity of the source of the problem.
At this point I'll change the code back to 0 delayed teeth and -305 degrees offset and drive it for a while and see if I notice any tachloss.

Thanks again!