Hello everyone, I purchased a ( WORKING ) MS-1 v3 from a friend of mine. It was taken out of his car by a shop and it probably sat around for about 6 months. I have recently installed it with the harness and for some reason I am getting no response out of it. I get no spark no fuel no anything. Just in-case I 100% messed up the wiring I plugged the megasquirt into my computer. All 3 LED bulbs on the megasquirt come on when the car is on but my computer can not see anything. How do I know if my megasquirt is just a paper weight???

 

First thing's first, the MegaSquirt Connection Troubleshooting Guide.

http://www.megamanual.com/connect.htm

What software are you using? MegaTune? TunerStudio?

Are you use there is firmware loaded on the MegaSquirt?

 

Sorry I could not answer right away I was out of state and did not have a computer on me. I have megatune and tunerstudio and have tried both. I have not touched any firmware on the megasquirt it self. Maybe im just being dumb and do not know how to work it. I put the key to on and plug the megasquirt into my laptop then open up the program. It always says fail to connect to com port 1 or somthing similar to that.

 

make sure you are trying to connect on the correct com port.

 

I tried going through every single com port and they all say connection failed :/

 

Im not sure if this will make a difference or not but im using a USB to serial cable. Not a serial to serial cable.

 

certain usb to serial adapters won't work. get the one off diyautotune.com for about $20. It works flawlessly.

 

I bought the megasquirt off of my friend and he used to connect it to his computer with the same wire im using now. So I really do not think its the wire in this case.

 

make sure you have a good power and ground to the ms.

 

im going to try a different grounding spot maybe because I know it is definitly getting good power. Is there anyway I can test to see if the megasquirt is like 100% dead?

 

buy or borrow a jstim board. I doubt it is dead. They are pretty hardy. Even if something was bad it would be fairly easy to diagnose.

 

Is there anyway to figure out exactly which part is bad?

 

Is there any kind of test I can do so that I would be able to determine what part is exactly messed up that way im not just guessing?

 

You need a JimStim or Stimulator board to determine if the unit is working at all. Second, you need to establish communication with the MS1 itself. Test the USB to serial adapter with another device and make sure it really works. Better yet, try it on another MegaSquirt you know is working and see if the computer side of it works.

Make sure the software and com port on your PC is working as well and there are no errors. For example, on a 64-bit Linux using TunerStudio, you have to change the serial library files with the ones specifically for 64-bit Linux or it won't work.

Once you can communicate with your MS1, you can determine which part of it is bad by using the JimStim to see which inputs/outputs are working or not. Also, you can check the board for signs of bad solder joints, broken or burned-out components.

If the megasquirt is working with a JimStim or Stimulator and the computer and serial adapter is confirmed working with another MegaSquirt, then you might have a bad serial chip, a 16-pin IC which is located on the board near the serial port, U6 I think.

Another thing you can do to see if your MS1 is working is to check voltages per http://www.msextra.com/doc/ms2extra/build_manual.htm at step 24.

 

Alright awesome I will definitely try those different things and figure out what is wrong with my MS. Sadly I do not have any friends with a MS I am the only one around. So I will probably end up buying a JimStim. Thank you guys for your help il let you know how it goes.

 

So after doing a bunch of testing and talking to people my megasquirt is not dead! I was able to connect my MS to the computer and get some readings off of it. Sadly I am still unable to get any spark out of my car. I am 95% sure the wiring is right. My coil is not telling my spark plug to wire. I check both terminals on the coil and they are both getting a positive reading while the key is on, but when I begin to crank the motor over they both still stay positive. To my understanding one is suppose to stay positive all the time and the other one alternate when cranking. What do I do now??

 

If you're using the stock ignition system, check your coils per the FSM: 05 Engine Electrical System. Coil with igniter.

Also, are you getting a signal from the CAS?

 

I think I am getting Signal from my CAS but I am not 100% sure. The reason I think I am getting signal is that when I opened up MEGATUNE and cranked the motor it told me my timing was 20.3 BTDC. Also when doing a little more investigation I noticed that one of my wires coming out of my CAS ( 1 of 4 ) was grounded completely when I am pretty sure it should not be. So maybe il check more into that as well.

 

Your CAS cable consists of 4 conductors (none of which are grounded) in a shielded cable. The braided shield is grounded at one end to chassis ground.

 

alright well I think one of my CAS wires is getting grounded out some how. I am going to trace the wire and see whats going on. Il let you know ASAP what I find.

 

ok..
im helping dylan here out with his car and im reading through this and i think there is some confusion.
Long story short.
this megasquirt used to run with this motor.
Motor was pulled out of the car along with megasquirt and eventually put into this 1st gen.
Now when the ecu was pulled out the wires were just cut off at the conection points.

So we put the motor in and now trying to get a spark.
There are 2 shielded wires to the CAS.And 2 regular blue wires.
3 of 4 are the grounded. 1 of two are the shielded wire.
So were do you go from here?
The wires are not touching anything.. just plugged right into the ecu.

ANy help will work !

 

I don't want to be captain obvious but with your laptop connection problem go into your device settings and check the port number the serial to usb adapter is using. I always make that mistake with new laptops/usb adapters. Cant get megatune to communicate and the darn thing is set to port 13 or something...

 

I was able to connect the MS to the computer but for some reason my ECU is not telling my coils to fire. Maybe something wrong with my CAS? Maybe the wiring is messed up

 

Refer to the factory wiring diagrams in the FSM for the correct wiring and wire colors for the CAS. Also, refer to aaroncake's write-up on wiring the MS--there's a diagram that shows how the CAS is wired the the MS.

Also, there are tests in the FSM that allow you to check the CAS.

 

Start from the basics and check your harness and connections. The worse part of buying a MS off somebody without a diagram is that you dont know what they did with the Ne+ and G+ signal wires... It can be connected through practically anything on the board

1) Check for source voltage at the db39 connector at all the voltage points

2) Check for good ground to all the ground wires on the db39 connector

3) Check for continuity through the N+ and then the G+ (CAS signal wires) Do this by unplugging the CAS and do a resistance check through the wiring harness. Your only checking resistance through one wire at a time. Cas disconnected and DB off the megasquirt. You should have very little to no resistance <1 ohms or something. Also, you gotta know what wires are paired so you might have to pull the hood off the DB connector and trace the wires to the CAS. Take notes of the wire place numbers on the hood, colour and which pairs with which because if its not the wiring harness, youre gonna need this info later to diagnose the circuit board.


4) Plug the CAS in and do a resistance check through the DB39 connector. Whatever pairs of wires you have for the cas. By this I mean N+ and N-. And G+ and G-. You should get resistance through this. Check the FSM for the proper specs but this test is actually testing that you have both a working CAS and a good connection to the CAS.

5) Start checking that the MS actually powers up when the DB is connected to it and the LEDS light up like they should.

From here on in its easiest to have a Jimstim to diagnose it because your trying to diagnose the circuit board. And a decent understanding of electrical circuit diagrams is quite helpful too.