KamakazieX

So from what I understand here on the forums the only modification to the megasquirt pcb is a 47k resistor on the LED(s?) and it will fire right up?

pmrobert

The value you want is 4.7K - note the decimal. That is 4,700 ohms.

-Mike

renns

Also swap R4 and recompile code or use EasyTherm to generate new lookup tables to suit stock air temp sensor. It's in the FAQ.

KamakazieX

Can someone get a pic of their megasquirt I v3.0 and show me what I have to modify on the megasquirt board so I can get it running?

(I'm going to throw this all on a page from CAS to modding the megasquirt v3 board. Hopefully people can throw some good tunes for base stock/fuel maps for stock na and turbo motors)

renns

Try reading through this thread. We found some glitches in documentation during that build, and I also had IgT and IgL reversed on the DB37. That's corrected on the second page.

https://www.rx7club.com/showthread.p...highlight=v3.0

Document your build well with lots of pics, and maybe a kind moderator will put it up as a sticky to help others. That would save lots of repeat questions, and make it much easier for those building their own units.

KamakazieX

I was looking at that post and reading the final steps of building a MS v3.0. What kind of firmware do you need to upgrade the megasquirt to before tuning?

How do you upload a configuration afterwards without it plugged into the car?

KamakazieX

... and does anyone have a tuned/working config they are willing to post for an NA 6 port?

I'm trying to find a good ign. table that is tuned real good, I can take care of the fuel part as long as its a turn key map in the meantime just to show it running.

I dont understand how you find 60 deg. BTDC and set the crank sensor to that??

Out of curiosity do I need the relay board or *should* I use the relay board?

pmrobert

See https://www.rx7club.com/showpost.php...0&postcount=13 for images of the process. Step 1: Set your crank to TDC rotor #1; I've included a photo of what a 12A front pulley and pointer will look like, the 13Bs are very similar. Step 2: Stab the CAS so it looks like the second picture in that message. The concept is that the ECU uses the first tooth after the missing tooth as it's solid reference point of what the crank angle is. We then need to tell the ECU where, in degrees, that "trigger" or reference tooth is set to in terms of degrees so it can calculate when to charge the coil and subsequently fire the spark when it terminates current flow through the coil primary. Since we need to charge the coil for a period of time (dwell time), 3/1000 second or 3 milliseconds is a good example and usually fire the spark BEFORE TDC, this trigger tooth has to be quite a ways before TDC so there is time to calculate and implement advance and dwell. Since the CAS wheel runs at 1/2 crank speed it is logically identical to a crank mounted wheel with 12 teeth minus 1 missing tooth. Dividing 360 degress by 12 will give us the number of degrees the crank will turn per each tooth, 30 degrees. If we mechanically set the CAS so the first tooth after the gap is opposite the VR sensor in the CAS at 60 crank degrees before TDC AND configure the ECU programming to this number (60 degrees) we will be in the ballpark and will be able to get the car started so we can finetune things so the calculated and implemented timing matches that seen by a timing light. We know each tooth in the CAS represents 30 degrees of crank rotation soooooo....
1. Set crank to TDC.
2. Set CAS position so the tooth representing 60 degrees before TDC (2 teeth after the trigger tooth) is exactly opposite the VR sensor. Look at the pictures, imagine the CAS wheel turning counterclockwise and you can hopefully visualize what I'm trying to explain.

-Mike

pmrobert

Also, any maps you get from other people should only be used to get you running. It's imperative that you understand your engine, your install at your location with your hardware. Comprehending the whole tuning process can be a little tough but it is well worth the trouble. www.megasquirt.info has a fair amount of data on tuning (developing an optimal configuration in all regards) starting from scratch. Especially - DO NOT USE someone else's map in the high load operating areas of your engine without working up to that point and reviewing logs as you go. The MegaLogViewer application will enable you to graphically view the data contained in your logs and can also suggest changes in the fueling parameters if you have a wideband O2 sensor. Suggested initial ignition maps are in the archives here and the factory RPM/load/timing graphs for 1985 are visible at http://smrmicro.com/v-web/gallery/Ma...t/Mazda?full=1

-Mike

KamakazieX

Has anyone tested the autotune feature? I was wondering if it actually worked.

How about the wideband O2 from DIY autotune? Can I just purchase the wideband 02 (~$70-80) without the controller portion and use it with megasquirt?

T2GTUS

You will need some controller ... not just the sensor alone. But yes you can hook up the 0-5v from a controller to the MS for display/logging.

turbosa22c

i think you can use the lc1 from innovate. its basically a sensor with the controller built in and has outputs to connect to a standalone.

dpf22

Actually, I don't believe that the uego sensor is built into the controller on the lc1, its connected with a common connector found on most wb02 sensors. I have seen them on bosch and ntk o2 wbuego sensors.

dpf22

renns

The WB controller is not built into the sensor itself. The LC-1 has the controller built into a lump on the harness. There's a serial port connection for re-programming the controller to scale the two analog outputs as needed.

http://www.innovatemotorsports.com/products/lc1.php

muythaibxr

I prefer to stay away from the LC-1. On some cars (for reasons I don't understand at this point), the analog outputs just keep frying over and over again, even when used with a resistor inline between the LC-1 and the MS.

Tofuball has had 4 of them fry on a daily driven car.

renns

I've dealt with Innovate LC-1 issues as well. The earlier units lacked protection from overvoltage and undervoltage situations, with bad grounds (sound familiar??) being a common cause. Warranty replacement has quick, and the new units have been fine. The issue has been discussed at length on the innovate forum, and they appear to have the problem licked with the added protection circuitry. In spite of the issues in the past, I'd certainly work with them again given their good value, strong technical support, and good warranty. FYI, units with "CLC" prefix on the serial number supposedly have the newer protection circuitry.

KamakazieX

My alternator is rated at 200A on my FC. Voltage is at 11.5 at idle and jumps to 15.6v when at 2000 rpms. Am I going to fry my megasquirt??

Tofuball

On THREE different cars, thank you!

Warentee replacement for me took a long, long time.

muythaibxr

We are going to try this out on one of our cars soon:

http://www.wbo2.com/2j/default.htm

Price with a sensor is about the same as the LC1. I've used the Techedge 2A0 for a while now and have never had a problem with it.

Renns: You are correct, the stock harnesses in most rx7's are in aweful condition; we can definitely say we've had our fair share of problems due to this, and in just about every situation, cleaning up the grounds fixes the problem. When it hasn't, a new harness has fixed the problem. However, we wired everything with his LC1 in such a manner that there should not be any ground issues, and we followed what the manual said to do. I've wired other vehicles in the same manner and not had any problems (including other rx7s).

Also, to renns, are you going to the megasquirt meet that's looking like it'll happen in April?

Ken

renns

I'd love to make the MS meet, but April's a bad time of year. A local MS event in the summer is something to think about...