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MS trigger options
https://www.slantsix.org/forum/viewtopic.php?f=26&t=53099		 Page 3 of 3
Author:  Matt Cramer [ Fri May 30, 2014 2:03 pm ]
Post subject: 
kcuf wrote:

only issue i have is that the usb to serial adapter i got from diyautotune wont function while the car is running with the coils,
works fine with engine off.


Running non-resistor plugs by any chance? They'll knock it offline as soon as you get spark.
Author:  kcuf [ Sat May 31, 2014 2:56 am ]
Post subject: 
i did go and reply over at msextra today, but yes, turns out i do have non resistor plugs, will have to get some with the R during the week,

i am back on the serial path now, i want to just change 1 thing at a time until i get it right, i "may" re-install the usb adapter again later, but for now i'll keep it out of the scenario now that i have a loaner laptop with serial.

one other thing i should look at doing as a test is adding more grounds, i have 1x 0.75mm sq cable straight to the battery, as i am still in testing phase, the MS is sitting outside the car on a chair, all wires running straight out over the front etc, VR sensor wire is shielded, 12v wire is the same 0.75mm sq cable, (18 AWG is probably a better number for you),
12v wire is straight off the batt with a 3a blade fuse, coil power feed is straight off batt with a 15a blade fuse, and a manual toggle switch (very very testing mode ;) )

after i try the plugs, i'll increase the grounding, when final install came around i was planning to run several grounds to batt, one or 2 to where the case mounts, 2 or 3 to the engine block, etc.
Author:  kcuf [ Mon Jun 02, 2014 8:25 pm ]
Post subject: 
resistor plugs = problem solved (so far), thanks Matt, working on a coil bracket now, lets see if having them perma mounted will change the situation.
Author:  Sam Powell [ Thu Jun 26, 2014 1:38 pm ]
Post subject: 
Mine worked better with all the grounds to a ground bus on the firewall. Stay away from the engine block regardless of what you read. I was getting interference from the starter motor through the block. It would read 3000 rpm during crank, and flood, and not start. Moving grounds away from block eliminated that problem.

Sam
Author:  kcuf [ Sun Jun 29, 2014 5:38 am ]
Post subject: 
so far mine seems fine with 2 batt grounds, 2 to engine, and 2 where the MS is mounted, all sensor grounds go back to the DB37, just need to get rid of my carby now!

have made some progress, rail is made, half way through making the jig to hold all the bungs to get them all level and in line etc, should have the manifold modded by the end of next weekend,
Author:  Sam Powell [ Tue Jul 22, 2014 2:32 pm ]
Post subject: 
Another note, all sensor GROUNDS on my BMW use shielded cable with shield grounded. Also, all engine management electrical has its own box on fender opposite of all other fuses.

On Dart I put ferrite chokes on all all wires that could emit interference such as alternator output. I also went back to resistance plug wires. This issue drove me nuts for awhile.

Sam
Author:  jcc [ Tue Apr 12, 2016 12:20 pm ]
Post subject: 
I don't see any followup on the reluctor notched damper solution. Did it work, fly apart, slip, break the crank, etc. ? I also would be hesitant to try, as much as I like the solution.

On the same issue, is there any extra room/wasted space to be found inside the stamped steel timing chain cover? I'd have no problem re configuring it, in order to allow the mounting of a reluctor wheel on the back side, with the same idea as another member did with the alum inside the backside damper adapter, That solution on mine with the romac damper, looks awfully tight/not doable, unless I gain some space with a modified timing cover. I'm just guessing, and try to develop a plan on a still running motor.
Author:  the_engineers [ Thu Jul 21, 2016 7:42 am ]
Post subject: 
If you're going inside the timing cover, would you be better off on the camshaft pulley? You'd be on actual timing events then and could fire "on time" as opposed to wasted spark EDIS.
Author:  Matt Cramer [ Fri Jul 22, 2016 9:16 am ]
Post subject: 
the_engineers wrote:
If you're going inside the timing cover, would you be better off on the camshaft pulley? You'd be on actual timing events then and could fire "on time" as opposed to wasted spark EDIS.


If you want full sequential, you're better off with a crank and cam trigger. Using the camshaft as a primary trigger lets any timing chain stretch reduce the accuracy.
Author:  the_engineers [ Wed Jul 27, 2016 8:35 am ]
Post subject: 
How would you integrate cam AND crank triggers? Can you feed both signals to MS, or would you need to combine them first?
Author:  Matt Cramer [ Thu Jul 28, 2016 9:04 am ]
Post subject: 
They're two separate signals.
Author:  the_engineers [ Thu Jul 28, 2016 12:51 pm ]
Post subject: 
So, is it worth doing? For whatever reason, I like the idea of iterating a cam position sensor a lot more than firing every 360* of cam travel...

Am I fixating on the wrong thing?
Author:  Matt Cramer [ Tue Aug 02, 2016 8:31 am ]
Post subject: 
The MegaSquirt uses the crank trigger as the main engine position, so there's not a functional difference in using the distributor trigger vs a cam sprocket mounted cam sensor. Whether the aesthetic difference is worth it is up to you.
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