Going Megasquirt

Give me a call, I can help you troubleshoot your issues.

Did you add the 4N25 optoisolators per the schematic? The output (pin 5) goes to "JS10". Do you have the 4.7k ohm pull-up resistor installed?
PM sent
 
I did add the 4n25 opto for the cam sensor. I changed the crank sensor circuit to match your drawings as well. I'll probably give you guys a call later in the week to see what we can figure out. Thanks, Dan
 
No problem. You still have my # right? Also ill probably be building another ms3 for a friend so the schematics will be fresh on my mind! Lol either that or on the boat drinking beer... ;) in that case I may not be much help at that moment.

Dan
 
Yea I've still got your number. I will probably give you a call later in the week.

Last night I connected ms3 to my laptop and played around a bit. I touched the crank signal port on the ms3 main connector to ground, and all of a sudden tunerstudio went from "Not Ready" to "Ready", and the fan showed that is was triggered.. This tells me that I have the crank circuit wired correctly, the ground turns on the LED in the optoisolator, which turns on the phototransistor and applies 5v to the crank port on the ms3 ecm.

Now I just have to figure out why my crank sensor isnt working..

How important is it to have the crank and cam grounds ran directly to the megasquirt? I've had them grounded to the engine block and no Im thinking that might be the problem?
 
I have all my grounds tied into a bulk ground in the adaptor harness which they don't recommend but it is also tied to direct chassis ground. Have you tried checking the sensor with the ground lead on the ms3 ground?

Dan
 
I havent tried it yet, and wont be able to try until friday.

blackturbocars said the training manual and the repair manual show different wiring on the crank sensor... "CRANK sensor:
Dark Green = +12VDC , Gray/Red = Signal , Black = Ground "

I guess I should try wiring it that way to see if it gives me anything. Is this how you have the crank sensor wired?
 
Daniel, you posted the 85 pinout. 12lbChevelle is correct. The 86-87 Crank Sensor Pinout is:

A= Power (Dark Green)
B= Ground (Black)
C= Signal (Grey/Red)

The Cam Sensor Pinout is:

A= Power (Grey/Red)
B= Signal (Blue)
C= Ground (Black)
 
Cal good call. Some day I need to do a good write up on here and transfer the good information to it... I just pulled up the schematics quick on my phone... epic fail on my part.

Dan
 
Hmm, I shouldnt have damaged the sensor by wiring it according to the gnttype drawing since both gry/red and green are supposed to have voltage applied to them.

I will swap the wires tomorrow and see if I get anything.
 
Wiring

Generally, hooking up the Hall sensor wrong should not damage it. (Most of the time).

Grounding the negative of the sensor at the block is fine IF you have run several grounds from the MS3 to the block as in the schematic provided by Dan indicates. Running a separate ground would help reduce electrical noise, but this has not been an issue. The signal levels are high enough above the noise on stock VIN 7 applications. I think you will be ok.
 
Woohoo!

I swapped the gry/red and green wires on the crank sensor and was rewarded with a crank signal!

Now to figure out cam signal!


Future megasquirt users need to note that the crank sensor wiring is wrong in the ecm wiring schematic from gnttype.org. Gry/Red = 12v, Black = Ground, Green = Signal (ground switching)
 
Good news, after doing some testing on the cam signal I swapped the 4n25 from the working crank circuit to the cam circuit and I'm getting a nice clean cam signal :)

Looks like Ill be heading to Fry's tomorrow to pick up a 4n25, and maybe a few extra just for backups!


Thanks for the help everyone, keep an eye out for a test start video tomorrow night!
 
:D:D:D

Went down to Fry's this morning and bought some 4n25's. I popped one into the socket in the cam circuit and it fired right up on the first try :cool:

As promised, here is a quick video running full sequential fueling and individual coil on plug ignition. This is running without even calibrating the TPS lol, obviously idling high, but I wanted to get a video for everyone to see. I'd like to thank everyone for the help, and I'd like to strongly recommend megasquirt to anyone who wants to spend a shirt load of time learning and tinkering. I have learned so much about electronics in the last 2 months working on this project. That knowledge has opened new doors for me already, and it will be with me for the rest of my life. Future plans are to get the rest of the car put together and add the usual sensors like fuel/alky pressure logging, vss, accelerometer, and even using an Arduino to use CAN communication for extra sensor inputs and maybe even a heads up display :)

‪Turbo Megasquirt 3 Chevelle‬‏ - YouTube
 
Im glad to see this 12#. You are just at the tip of the iceberg though as far as stoked goes, wait until you get on the road and get to screw with all the features and benefits MS3 has to offer!

Dan
 
Update: Works great! Been daily driving it to work since the week after I first fired it up. Literally just as reliable as a stock ECM. I can get in the car and fire it up at any temperature and it will start and idle like stock. I played with the 2 step a bit and it is pretty sweet! I dont have my alky kit installed so I havent even started tuning for WOT but for everyday cruising it has been a blast.

I have a transmission problem so I am building a 4l80e in my garage this winter which I will run with the MS GPIO board.
 
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