I am going to reseat my CAS when I get home later and I wanted to verify the new procedure:
Set the engine to TDC (I have 12a), remove the CAS and set it to the normal dot mark.
Looking from the top, turn the gear 3 teeth clockwise(?). (to where the two tooth wheel is lined up with the reluctor?) Restab it while making sure it doesn't move

Set the MS to:
Trigger angle: 60
Trigger positions: 1,3,7,9.

To rezero, set fixed angle to 0 (12a) and adjust the CAS.

Sound right?

On a side note, Is it advisable to restab the CAS with this procedure on a FC when converting to MS, or have you seen the exact same results with either trigger position setting?

 

That's not quite right... you want to have the third tooth on the 24 tooth wheel to the right of the tooth on the 2 tooth wheel lined up with the 24 tooth VR sensor...

I'm assuming you have cut 2 teeth out since you thought you were having problems with the second sensor (or am I mixing you up with someone else?).

In that case, just turn the CAS to the third tooth after the missing tooth, and stab it, making sure it stays in that position... then set the fixed angle in the MS to 0, and start up the car... and use trigger angle 60 with 1,3,7,9. Keep in mind that when the engine is running, looking at the CAS from the top where the Ne/G wheels are, the CAS spins counter clockwise... so with the Ne wheel's vr sensor facing up, the third tooth to the right of your missing tooth is going to be your TDC setting, with tooth 1 being 60 deg btdc.

On the FC, if you're going to use the stock way of stabbing the CAS, you'll want settings of 60 degrees trigger angle, and 11,1,5,7 as the wheel decoder settings... You'll have to turn the CAS a bit to get the timing just right, it'll be about 5 degrees off from the stock position if you do this.

You can really stab the CAS any way you want.... as long as you compensate using the wheel decoder settings and trigger angle.

 

No, it's a normal stock CAS. With this in mind, is there a better way than what I outlined?
Should I be using 11,1,5,7 and stab it normally instead? The trigger positions got me pretty confused, I really need to read up on it, but I am trying to be lazy...

I was having cranking problems and could not use trigger return. I am hoping this new setting will allow me to use trigger return instead of time based so I can get slightly better starts, though it is starting okay right now.. At least, last time I drove it which was almost two weeks ago...

 

Like I said, it's up to you, and no way is better than any other way as long as you have it set up right.

If you stab it like normal, and you have the CAS open, just make sure tooth #1 is lined up with the VR sensor after you stab it with the engine at TDC.

If you can't get the timing light and the Megasquirt to agree, then you still have something set up incorrectly.... maybe you reversed the leading and trailing outputs? (that could potentially give you timing on leading that's 15-20 degrees retarded). There's just so much that can be done wrong when doing a setup like this... especially if you built your own wiring harness etc...

For example, if you have the Ne + and NE - wires backwards, your timing will be really hard to get right, same for getting G+ and G- backwards.... if you mix up leading and trailing IGt, then leading will fire when trailing should, and trailing will fire when leading should, which would also be a bad situation, and would make it impossible to zero the timing properly.

I strongly suggest reading up on my wheel decoder howto/explanation. Some of the stuff in it is out of date, but the concepts are still the same:

http://www.speakeasy.org/~culverk/wh...oder-howto.txt

 

I have 0 problems with timing. It's spot on, the car runs great. No discrepencies with the timing light or MS. I've never had any issue with this, actually. Well, after I finally stabbed the CAS correctly anyways.

The only issue I have is that I cannot use trigger return crank timing. I just recalled from a previous post that you recommended that I change my setup slightly (ie, the CAS settings)and this may enable me to use trigger return instead of time based. Though, I've forgotten what I did with that info... Figured I'd just ask again.

I seem to also remember that tofuball was running a different trig. pos. than what you had in the FAQ and that you saying this may be better for v2.2 boards...
Again, however, I forgot the details.

 

hrmm, yeah tofuball is using 1,3 7,9 settings, but I think the issues you were having with trigger return were related to the cranking advance you were ending up with on your setup. Tofuball and I have had no problems getting trigger return to work well provided the CAS is stabbed correctly and the cranking advance is either -5 or 0 based on the trigger angle and trigger/return settings. I've tried it with 12,2 6,8; 1,3 7,9; and with 11,1 5,7. With 11,1 5,7 and the CAS adjusted to exactly where it should be for stock, the car backfires a little bit (because it's cranking at 5 deg btdc) but if I adjust the trigger angle to 60, and turn the CAS to match, trigger-return works great.

Something else you might want to do to get better behavior from trigger-return is to set your cranking rpms a little higher. If you have it set to 400 now, try 500 or even 600... after the car has been running for a couple of seconds, it won't go back to cranking mode, so it doesn't hurt anything to try.

Ken

 

Thanks Muy,
I was just about to ask you about the restab with the two tooth removal. I do understand your explanation. My fixed angle is still wrong though..I believe its set at -5 right now. Its been 5 days in a rom with consistent spark each day,car wont start fron timing being off and battery is weak. Working too many hours lately to play with it much,Shawn

 

I also wonder if my problem all along was the daughter card? Since its destruction and the 2 tooth mod I've had spark ever since. Yea I had a couple days without spark at first but I had to readjust the pots..I had adjusted everything so much trying to get the d card workin I think that was my own doing. Supports my belief that the LM1815 chip decided to quit on me. Just thinkin here dont have time for anything else,Shawn

 

I restabbed the CAS at "tooth 3" and set the trig positions to 1,3 7,9. Trigger return works! Even with 0 wait time.
Starts real well now. Right on...

 

Cool! Glad to hear it. I'm going to mess around with the settings here at home as well just to see if any one setting is better than another. I never had any trouble getting starts with any settings I've tried, but we'll see.. I was also thinking about rewriting the "return" part of the code....

Right now what happens is there's a section of code that executes every time a tooth passes the VR sensor, and a section that executes every .1 ms. When a return tooth passes the VR sensor, a flag is set, and the next time the .1 ms code executes, it fires the spark plugs.... That might be a little weird sometimes because the part of the code that checks for the tooth on the 2 tooth wheel also executes there, and may be causing just enough delay to make a difference. I'm thinking about making the spark plugs fire on the return teeth directly from the part of the code that executes when the tooth passes the VR sensor... which will get rid of that delay. Does that make sense? (just want to make sure you can understand my explanation).

 

Well, it seems I spoke a little too soon.. My hot starts are still a problem. Grr..
I am not convinced that it is any sort of wheel decoder issue. Maybe heatsoak or something else going on that is causing it. I'll have to mess with it as I get more time. I let it go up to 100 or 120 degrees and it was starting fine but at full temp shutoff and restarts get finicky.

I read your wheel explanation and I don't see how the wheel decoder settings could be effecting my trigger return/cranking problem..it could be my imagination, but cold starts are indeed better/faster and I definitely feel better about trigger return than time based.

Also, this "3 tooth/1,3 7,9" method is definitely the method I would use to install a CAS for use with MS on a rotary, at least on a 12a because it centers the CAS on the adjustment stud much better than the stock stab method.
Actually, out of curiousity I checked the front covers of both a FC 13b and a 12a to see if the studs were in different places, but I couldn't tell. So far as I could see, they are the same.

So, the .1ms section checks for the "fire flag", so to speak? If that's the case, I guess I got it...
Sounds your new way like that would be a better.. Though, I'm really lost when it comes to the coding for these things... If you get it coded I will be happy to beta test it and see if it helps my hot starts.

 

Where is your air temperature sensor located? If you're having trouble with hot-starts, that is likely the culprit. I'm not sure why I didn't think of it before....

Could you tell me the next time you have a hot start problem what the temperature of the air temp sensor is, and what the temperature outside is?

You got the "fire flag" thing. That only happens on trigger return cranking though... The rest of the time below about 2800 rpms (it depends on your settings, there is no set rpm number), there's a microsecond timer that's used for spark and dwell, and above that, the .1ms section is used for dwell (because if dwell overlaps, you need more than one timer to handle it, and dwell gets close to overlapping there), and the microsecond timer is used for firing spark.

 

It's located in the air cleaner housing.
http://www.mindspring.com/~wilkinsjr...0compelted.JPG

I'll check the temps next time I mess with it, hopefully later today.

Actually, dunno if you remember but I'm trying to sell off my EFI stuff along with my FB. I was going to take all that stuff off today, but I think I will sell it off with the car via ebay complete. So, for the next couple weeks I'll be able to keep tinkering..

The manifold is thin aluminum. It does absorb quite a bit of heat. I got a ceramic coated exhaust manifold installed recently, though I haven't had a lot of time to gauge the effects. Hood temps are lower, though they creep back up if it sits at extended idle periods, normal driving though and they get back down to about ambient, which is real cool. (pun intended haha)

 

Crap!
I tinkered more with it today. I can't get trigger return mode to work, at least on hot starts. Time based works well, though. I tried -5, 0 and 5 as my cranking angle with time based and they all worked fine. Heatsoak doesn't seem to be an issue.
With trigger return mode, I tried a wait time of 0 and then 3, same results, it just won't start. Tries to, but no good.

It's a different start sound, though. If I go into flood clear, it makes a certain starting noise, then if fuel is getting injected like normal it makes sounds like it is wanting to start, and almost gets to the point where it will, but doesn't. Hard to describe.. No amount of throttle seems to help its starting efforts.
Also, there are occasional backfires with trigger return mode which leads me to think it may be some kind of time calculating issue like you said. I am using 60 trig angle, btw.
Tomorrow I will reset to trigger return and get a timing light while somebody cranks on it and see if I can tell where exactly it's firing...
Seems like if it's 5 or 10 degrees off, it should be starting, so maybe it is WAY off somehow, but I have no idea why that would be. Maybe something screwed up the timing calcs somehow and it for some reason fires somewhat randomly? No clue at this point.

 

if it's way off, you may want to check your wiring, you may have the Ne+/Ne- wires backwards, or the G+/G- wires backwards... that can definitely cause problems like you're seeing.

Also, did you try setting it to time-based, setting the cranking advance to 0, then setting it back to trigger-return? If you don't do this, the cranking dwell will be erratic at best. You have to have the cranking advance set to the angle of the return teeth. I KNOW trigger-return works however, even with the latest code (029d, going to post it soon in the firmware thread). We just updated tofuball's car to 029d, and it starts up in half a crank... I mean almost as soon as he turns the key the car starts.

Last, what is your cranking rpm set to? Tofuball's is set to 400 rpms.

 

I'll check my wiring, but I just can't believe I made that mistake. I was very careful and I have no problems other than hotstart cranking trigger return. Wouldn't crossed wires cause other problems as well?
I'm sure trigger return works, but why it's not working I have no idea right now.. :-/
I've done that before, setting cranking advance to 0 on time based.. I'll try it again, though.

I could just use time based and call it a day, but I have to say that I am pretty curious to find the cause...

Oh, and I am using 400rpm for cranking rpm.

 

Okay, now I am really stumped.
I got the timing light and set trigger return, hold 0. It is firing dead on TDC!! But for some reason, it won't start. Acts like it wants to, but doesn't. Allllmost does then goes back to turning over and repeats, just doesnt get there, backfires.. etc.

Any ideas why this would be? Time based works, I can always get the car started with it, and usually it starts right up. It definitely does not fire on TDC, but gets there.

Trigger return does work at cooler temps, btw. Seems like the hotter it gets, the less likely it is to start. As this happens, I can manipulate the throttle a bit to get it started, but at full temp, it absolutely will not start with trigger return.

I increased cranking rpm to 500, same, also tried a much richer cranking pw, same, leaned out the cranking pw, same...
Maybe it is just my setup, though I don't see how that could be. Veery curious. I am missing something here.

 

Have you tried changing the amount of fuel on cranking? Tried setting the cranking rpms higher... like 500 or 600? I also forget... what version of the firmware are you using?

 

jayroc, might you have a vapor lock situation in your now-heated fuel rail or pump during warm start? Winter fuel is more volatile, I'm told, and is thus more susceptible to vapor lock.

-Mike

 

Well, today was real warm. About 55 or 60 degrees out.

Here is the wiring that I have going on:
http://www.mindspring.com/~wilkinsjr...%20Wiring.html
I am going to reverify it now, though I suspect this isn't the problem.

I'm using the 26i_mod firmware. I changed the cranking pw from 4ms to 9ms in extremes. 5.8 is where it's happiest. I've raised cranking RPM to 500, but no change...

I don't know if it's vapor lock. If I set it back to Time Based it starts everytime. Not immediately mind you. The longer I try trigger return the harder it gets, I suspect it is almost flooding.

Is it possible that it would show it's firing at TDC, but not firing often enough? If it's firing at TDC like it should, what do the backfires indicate?

 

The backfires can indicate too much fuel or that the sparks aren't firing every time... most likely too much fuel though. I'd suggest decreasing the amount of fuel for sure though, as tofuball and I are using a value of 3.2 ms for hot cranking, and it fires right up with trigger return.

 

I lowered the pws to 1ms and it still does it. Increased slowly to 5ms, but it still won't start.
Weird thing is that sometimes it will start immediately, like it should, with weird pulsewidths like 1ms or 2ms, but if I shutoff and restart, it will not start. Usually, there are wierd backfires, or popping noises.
Gunna try this new flash you got...

 

if you have fuel and you have spark, you should be able to start the car up... Kinda makes me wonder if the MS is missing the return teeth for some reason... Did you ever post your msq file? that'd be very useful...

 

My MSQ file. http://www.mindspring.com/~wilkinsjr...n30%202330.msq

I have reflashed and it still does the exact same thing.
I tried the version 24s9 decoder setting, as well as version 25. Also, I tried rising and falling edge triggers, but same results.
I am convinced this is a spark problem, but what kind..no idea.

BTW, I am on 29d now. I reentered all my settings manually and reimported VE and spark. Using MT757. I may have made a mistake, so if you see anything, lemme know!

 

Like I said before, if you have spark, the car should start... and you confirmed that you have spark...

I'll look at the msq when I get home.