My experiences with Megasquirt

[2projects2many]

What were saying, is that we believe that the smaller of the two wires is a secondary signal wire that is not used for MS. When this wire is grounded or hooked up to anything but a stock ecu, it may interfere with the distributor. Its just an electrical unit, hooking it up incorrectly can cause it to stop sending a recognizable CAS signal, or possibly fry your dizzy.

Also with as cheap as you can score a second s13 dizzy you should have a second one to make sure that your problem isnt just simply a damaged CAS.

EDIT - Zig man, its so much easier, cleaner, more reliable to just rewire your whole engine bay. You condense what was originally 2 pounds of wire down to 10-15 strands that YOU know how they were run, how to trace them if there ever is a problem.

I'm going to let it charge overnight, and tomorrow, I'll remove the little wire from ground, and connect the large one right beside the white wire, and verify my 12vt input again on the blk/wht and the see what I get. I'm also going to see if I can find anything on testing the pickup sensor to check and see if it I may have fried it.

[2projects2many]

This is why when I did it, I got an ECU pinout diagram and an ECU wiring diagram. It's a lot easier if you do it right at the stock ecu harness end and then just leave everything else alone.

That's what I did Zig, just cut the stock ecu harness connector off and tapped everything there. Where did you mount your ms? I'm not sure if I can squeeze all this into the factory ecu location. The glovebox was my initial thought, but after cutting a hole in that for the wiring, it would bind when opening and closing.

[krazydriver]

Zig man, its so much easier, cleaner, more reliable to just rewire your whole engine bay. You condense what was originally 2 pounds of wire down to 10-15 strands that YOU know how they were run, how to trace them if there ever is a problem.

^ i'll have to take some pics tomorrow, i just did that over the weekend. Clean as hell. I'll also show you how much factory stuff came out.

2projects, The ground from the CAS is black with like silver dashes down it, this wire actually is NOT with the normal CAS wiring. It ties into a shared ground with the TPS and the CLT. The power is black with a solid white line, white line is the signal and the other small black don't connect.

If you cut and taped everything from the factory ECU i would verify that all the grounds are properly regrounded. But as was mentioned checking or swapping the CAS would probably be good.

[ZiG]

Actually the glove box works perfect if you leave a bit of slack in the wire and make sure you cut a big hole in the side.

[2projects2many]

Alright Krazy, tomorrow I'll be sure to remove the small wire, and insure all grounds (Black with silver)from the ecu wiring are in fact grounded. I'm also going to look back up on ms site and basically rework all the steps since I initially set this board up to trigger from the coil (no ignition control) and make sure I have removed & added everything needed. Thanks for all the help guys, I'm going to get this thing going- I won't be beat!

[2projects2many]

Actually the glove box works perfect if you leave a bit of slack in the wire and make sure you cut a big hole in the side.

I did cut a hole- just not that big. I have the slack- so I'll probably go back with that. Thanks for the suggestion.

[480sx]

I know you havent really liked/approved of my setup from the getgo, but there it is.

What? Where did you get that from man..

Anyone with the balls to try MS and the skills to get it running is alright in my book. All i ever said was that i felt like you should have gone with MS2 i believe. I dont even think i said your setup was probably acquired through food stamp trades..

I mounted the case with zip ties up to the blower motor on the far left hand side of the passengers foot well. It was a pretty ideal spot, you could easily get to the com port and it was out of the way.

[2projects2many]

I dont even think i said your setup was probably acquired through food stamp trades..

Now dat some funny $hit!

[2projects2many]

OK guys, so I had to buy a new charger 'cause I charges overnight and the voltage was the same. So I got the battery back up 12+ vts, and was messing around after checking the wiring and everything looked good. The small wire is the correct ground wire as it has the silver dashes going down it like all the other grounds. The odd thing is though while I was cranking I decided to jumper the D2 as suggested in the msns manual, and what do you know I received a little rpm (around 98), so I say to myself "why don;t I remove this diode as well and jumper permanently and see what happens. Guess what? Nothing- not even the little bit of signal I was receiving when the D2 was installed. What the hell is up with this damn thing. I rewalked all of the V3 ms1 board assembly instructions, and see no errors. Any ideas?

[480sx]

The black wire with white dots on it is the engine ground. The small black wire is the wire you just tape up.The white wire is your signal wire.The black wire with the white stripe is 12 volt.

Make sure you have that right first.

So, your saying that you were able to get a cranking signal, then you changed your setup and now you cant get one.. It sounds like you might have had it right, then you messed it up. Are you sure your battery was fully charged when you got your 98 cranking rpms?

[2projects2many]

No 480, it wasn't fully charged yet- @ about 95% though. I had D2 diode installed, and was also jumping it when I got a signal. I decided to remove it since I got something by by-passing it, but than nothing.

[2projects2many]

OK, so I install D1 back on the board, and try to crank- nothing- so I short out D1 and whammo- tach signal. I crank and adjust and crank and adjust- re-position the distributor to TDC, and get back in to crank. Guess What? No tach signal again. Any ideas?

[480sx]

How many times have you read the mega manual and understood it?

http://www.megamanual.com/index.html

This is how everyone else gets theirs to work. It gives you pretty much everything you need to know. Anything thats not KA specific has already been gone over and explained on this forum. You can also join the forum specifically for Megasquirt that has quite a few members.

http://www.msefi.com/index.php

Also, have you gone through and followed every procedure in the two part section of the mega manual for setup and tuning?

It sounds like you rotated your dizzy to far. Rotate it back the way you had it and you will probably pick a signal back up. You need to set your crank angle, so the MS knows where the engine is on its firing sequence.

[2projects2many]

How many times have you read the mega manual and understood it?

http://www.megamanual.com/index.html

This is how everyone else gets theirs to work. It gives you pretty much everything you need to know. Anything thats not KA specific has already been gone over and explained on this forum. You can also join the forum specifically for Megasquirt that has quite a few members.

http://www.msefi.com/index.php

Also, have you gone through and followed every procedure in the two part section of the mega manual for setup and tuning?

It sounds like you rotated your dizzy to far. Rotate it back the way you had it and you will probably pick a signal back up. You need to set your crank angle, so the MS knows where the engine is on its firing sequence.

480sx, I read over 2-3x, but I can't say that I have it memorized. Additionally, regardless of how I rotate the distributor- there's always should be a signal- rotating it simply tells the computer when the engine is in position to send an ignition charge (thus explains "ignition timing") I'm not new to cars, nor their systems- just new to controllable fuel inj/ignition. I appreciate the ideas and info you've given. What confuses me is that I change out a diode and nothing- I short said diode out and than it works. I get out to recheck timing (adjust distributor) to see if I can get the spark on time & than no signal. There's either a problem on the board, bad connection in the pins/wiring, or possibly a bad distributor. I get another ordered for this weekend, and check it out.

[480sx]

I mixed up a spark problem with a cas input one.. Bad info. Been a while since iv done this stuff and am no expert. The guys on the MSFI forums are the real people to ask.

Still it makes sense to try put everything back the way you had it when you picked up a cas signal and try again.

[2projects2many]

Guys, I got it somewhat running this weekend. Only with my foot mashing the pedal to the floor though. I can't get it to idle or go over 1400rpm with me holding the pedal. It's dumping loads of fuel though= just no way to keep it running. I've stabbed the distributor 3 more times to make sure I had it right. I don't know where to go from here. I guess maybe the cams could be wrong- but I was really careful when assembling this motor to be sure all was right- so I don't think so. Any ideas?
Modified by 2projects2many at 10:04 PM 4/28/2008

[480sx]

Have you tried.. Pulling fuel from the idle bins?

Man can you just start another thread with a list of your problems so we can get this clutter out of this thread? This was meant to be a thread so people who had no idea about MS could come and read our stories, not listen to us try to trouble shoot random problems.

[2projects2many]

Thanks for the help. I'll get going on that.

[sil80drifter]

sorry to thread jack a little, but it's somewhat related - A year later than I thought I'm finally startin to wire my MSII setup.Does anyone know whether the following diagram (resistors and transistor) is valid (needs to be used) for the 89-90 s13 tachs?

http://www.msextra.com/manuals...o.GIF

This was posted in the very first post in this thread, but the guys' car was a 91-94, and I know things changed in that generation a bit.

My god... I haven't posted in like 4 months... good to be back!

All input is appreciated by myself and of course whoever else squirts a SOHC.

sil80

[ZiG]

I do believe it is. But there's a real easy to tell: wire it up without it and see what happens. Worst case scenario should be that it just won't work, then you can pony up the $2 and solder that circuit in.

[sil80drifter]

ZiG, appreciate the input.

So, if it's to be hooked up without the resistor/transistor circuit, it's just having the IGN OUT wire go straight to the tach? I'm kinda afraid to fry the tach if the signal's too strong without resistors...

sil80

[ZiG]

Yeah, you would just connect it directly. But I really don't think that will work, I'd put money on the 'it will need exactly the same circuit as a dohc cluster' option.

[sil80drifter]

I got all the parts for that anyway, so I might as well do it the same way, and i can always disconnect and run it straight later.I'll keep you guys posted,Thanks!

sil80

[sil80drifter]

Wait... I'm a bit confused. Does this circuit imply I should apply it to pin 24 or 36 on the msII? i.e. isn't technically pin 24 the "tach" pin, which receives what usually would be input for the tachometer (save the low voltage adjustment)?Or is Pin 36 both the output for the negative coil terminal and into is I should splice in the circuit with the resistor/transistor?I know it sounds like a stupid question but it's almost 2 am and my head isn't workin rite now.

sil80

[ZiG]

the output pin for the tach is not the same pin as the one for the ignition coil.

[sil80drifter]

OK, so what wire usually goes to the tach (when it's not controlled by the ECU)?I assume the positive one on the coil?

So I'll take my positive coil wire and splice it off to the tach, but put in the resistor/transistor circuit in order for the tach to read correctly?

Or should I get the tach signal from another source, such as one of the wires that goes to the MSII? Such as pin 24 or pin 36?

sil80

[ZiG]

What? No. You're gonna fry it. Aftermarket tachometers connect to the NEGATIVE pole on your ignition coil. Since that's the pole that triggers it.

Just wire it up exactly as I've shown and it'll be fine. You have to go into megatune and fine the 'tacho output pin' setting and look at it. It will say blah blah js0, blah blah make sure this pin isn't already in use, etc. Then enable it. Then open the case and find JS0 (it's on the bottom of the PCB). Now solder a wire from that spot to an unused pin on the plug for the harness. Since I bought the premade pigtail, I just soldered the wire to one of the iacv stepper motor wires since it's not in use. Then you connect that wire to the transistor circuit and to the wire leading to the tach, which you can just cut off the stock ecu plug and then it's right there.

[sil80drifter]

Why am I going through the MS, when I could splice it out of the negative coil wire? I mean the MS is already getting the RPM signal, right?

I could technically splice off the resistor circuit off of the Negative Coil terminal and into the stock tachometer, right? Your suggestion was mostly just so that I keep everything wired from the MS, correct?

sil80

[sil80drifter]

So, since Pin 36 on the MSII IS the one that connects to the Negative Coil terminal, so I would be splicing and adding a resistor circuit to that wire (see diagram for 89-90 KA24E in the below pic), correct?



sil80

[ZiG]

Well, you could try it. I have no idea what would happen. It seems that with that transistor circuit, it's working with a positive signal, so if you were going to try connecting the tach to pin 36, you might just hook it straight up without the transistor.

Oh, of course if you do it this way, and use a rev limiter or launch control, etc, your tach will go nucking futs whenever the limiter engages.

Seriously, I really think you should just wire it up the proper way, with the dedicated pin on the ms and the transistor circuit.