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anyone in phoenix with megasquirt who could test


JIM73240Z

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I have my megasquirt in my car.  I can connect and load a program, it reads tps and temperatures.  I do not get a tach signal when cranking.  I was wondering if anyone could test the computer to see if it has a problem or the wiring.  if it is the computer, I swear I will take it out to the gun range and then go get a haltech.  if it is the wiring, I will order a new wire harness and redo it.  I do not seem to find the issue.and I would like to narrow down the issue.

 

thanks in advance.

 

Jimbo

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I happen to see Jimbo ( the OP) today and told him I would like to help get the car situated. Full disclosure I have never messed with the Megasquirt line of EFI but I have installed both Haltech and Nistune unit on my cars. I'm trying to pull up a wiring diagram and read as much about the installation as I can so I can get a basis for where the system is in its current state. I 'm also going to go over the wiring w/ Jimbo and make sure everything is in the right place and hooked up properly. Thanks in advance for your help!!!

 

Ok, so was this unit made to provide spark from the BIP ?. Or do you need a another way to provide ignition for the distributor??...

How do we check that? FYI He has no pigtail for the dizzy so its connected directly to the bottom of the dizzy.  Also if i read correctly the 1k resistor gives the G/B wire for the dizzy 5v right. So I should 12v for dizzy power then ground and finally 5v to the G/B wire terminal. Is there a way visually on the MSII board to see if it is getting the ignition pulse from the dizzy?

 

Are you getting rpms in software and showing a crank trigger while cranking?

According the OP there is no tach movement and nothing on the software indicating that the motor is turning over although he is cranking it. No spark what so ever.

 

Did you set it up with the 1K pull up resistor(s)?  Stock CAS wheel or the DIY wheel?

It is the stock wheel. I will double check about the resistor. I didn't see it by the dizzy wiring but I don't know if it's been done over at the ECU board side. I dont think so and that maybe one problem.

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I ordered a resistor and soldered it in.  I will check my receipt from where I got it.  It has been at the shop for several years as I got the chance to work on it and it is basically done.  I had a 3.57 board and I killed it so I got a 3.0 and built it.  i am going to check my build manual and double check the steps and tests.  while it is still in the car, i am goint to pull the dizzy out and turn by hand and see if i get any changes and test voltages.  I have the stim and I got some movement on the computer by turning the knobs.  it has been a while since I did it.   the big thing is trying to narrow down the problem.  is it the computer or the wiring?  then go from there.  if my computer starts up someones car, then.......   the car is at home now so I can get up in the middle of the night when I cant sleep and go tinker.

 

jimbo 

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  • 1 month later...

so I ordered a new stim (prebuilt from diy).  I have o2 readings now.  I can test the tach on the stim, it works, without being plugged in to the ms.   then plug in the ms and nothing.  went over step by step, and have o2.  I thought I read that you could not have an o2 without tach.  all of the dip switches are off as I am running a 83 dizzy.   soooooooooooooo, wtf.  is there a set up that I have to do on the stim, certain jumpers, to make this thing work?

 

frustrating

 

jimbo

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How is the following configured on you v3.0 mainboard?  This area gets the tach signal in from the zxt optical dizzy to the megasquirt processor.  

 

For the Hall sensor, optical sensor, coil negative terminal or points:

  • Jumper XG1 to XG2 on the bottom side of the PCB, near the 40 pin socket,
  • Jumper OPTOIN to TACHSELECT on the bottom side of the PCB, near the DB37 connector, opposite the heat sink.
  • Jumper TSEL to OPTOOUT on the bottom side of the PCB, near the center.
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yep.  all there.  now when I built this, I followed the ms2 manual.  I have the ms2extra in there because I wanted to try the bigger maps.  I have been looking at the ms extra site and trying to figure out any differences.  at this point, I will scrap the extra and try straight up ms2 if it will get the car started.

 

jimbo

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You might have already mentioned this, but I would put a voltmeter on the wire coming from the dizzy to megasquirt (the one with the pullup resistor).  You will be able to watch the voltage and slowly rotate the dizzy.  As the dizzy passes each slot on the optical wheel you will see the voltage change.  If you go slow, you should be able to see the reading at full voltage (whatever you are pulled up to) and then zero volts and so on as the slots are passing through the opto sensor.  If you rotate it fast the voltmeter doesn't have time to respond.

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car is at the shop right now.  the way I figure it is to isolate the issue.  could be wiring, could be computer.  not sure so take one thing at a time and make sure that at least one thing works.  I will check the voltage drop by the end of the week.  but the computer........  I am just trying to verify that the computer is working.  parts are, but I am not getting a tack signal on the stim.  that tells me there is something there.  once that is verified to work I can concentrate on the wiring.  when I bought the stim, I also got a new bundle of wire to rewire it if needed.  I am looking for 5v right?

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