Robgrob

Im not sure I understand your question.

The OEM ECU is completely removed and replaced with a new one. The Megasquirt ECU does not need a MAF, that is why I removed it.

You can run a MAF sensor, but not the OEM sensor as the megasquirt requires a 0-5V MAF. The OEM MAF has a completely different output signal.


The stock OBD1 cars run much better with the MAF sensor simply unplugged on the stock ECU though. You should try it. But the milage will probably get worse.

Robgrob

I have now updated the thread with my most current tuning file.

187

Any specific reason you couldn't get any more power with more timing?

I wonder how much you could get out of the vvti with something like this.

Lettut

Great build thread! Subscribed.

Glad to see one more SC400 in Scandinavia!

eefmydee

thank you rob for your response and yea that was a stupid question and i understand now, where did you put the updated tune, and at what elevation are you at? just curious?

Robgrob

The engine did not respond to more timing. More is not always better, this is even more true on an NA engine where the MBT often can be reached even at low octane fuel.


The VVTI engine is miles ahead in cylinder head and intake manifold design. Im sure that engine has a lot more potential.

Robgrob

Im at sealevel, but it should not make a big difference.


The updated tune is in the first post.

dricacho

Glad I found this thread! I also have a 92 SC400 and I'm on my 3rd ECU, those old first gen ECU's have really old capacitors that will just leak and render the ECU useless. My initial plan was to send the old ECU to Driftmotion to have it repaired but now that I saw this thread, I would love to get the MS ECU instead. Also, I want to get rid of the old gauge cluster which is also falling apart due to very old electronics and use Real Dash instead. It so happens that it will work with the MS!! I have never done anything like this before, this is my first aftermarket ECU install.

I just have a couple of questions just so that I'm sure what to do:

1) As for connections, is there any other modifications needed physically on the car's harness or is it just like it says, plug and play?

2) As for AFR, are the stock upstream O2 sensors unusable hence needing a wideband sensor?

3) Which one is the options connector on the ECU, is it the one that has it's own connector on the right side? I'm assuming the instruction to wire up the options and wideband O2 sensors are included in instruction manual that came with the ECU.

Thanks for your contribution and knowledge.

ihiryu

iTrader: (7)

After looking at his tune file, it's plug and play, he made changes for the ignition output, so all the changes were done via software.

You can use the stock narrow band if you choose but trust me, it's not worth it. Weld a single wideband into the Y-pipe.

Options connector is the serial port on the ECU. I sell a lot of the MS3 units, and use it on a lot of different cars. Shoot me a PM if you need some help

oldManTan

can you use this to control the stock auto?

dricacho

Thanks for the reply. Mine is also an auto, would the MS3 work as well?

BAD954BOI

iTrader: (5)

much props nice thread.. i wonder where the build will end up..subscribed

BartleDoo

iTrader: (1)

I've been off CL forever and I can't believe more people haven't taken tried Megasquirt given the cost of a DIY kit and the results vs the crappy old ECU. The MS3 capable of running the 1UZ's original hardware has been available for so long! Mine has been running without any issues for several years as OP has probably experienced in his other MS applications. Good luck and hopefully more people ditch the stock ECU.

Robgrob

Still some activity in this old thread! Car is sold, so the thread has come to an end for updates unless the new owner comes back for a supercharger tune I will ofcourse share that tune with you

A quick answer of the questions here

1. I dont think it can control the A/T, however since this is an open source project there may be some way of doing it. I have never had an AT, so I never looked into it.
2. You can use the OEM O2 sensors for closed loop fueling, but not for tuning. I ditched them and used my wideband for both.
3. This is a true PNP install, read the first page. You need to loop a connector on the side of the new ECU, thats all.

Hope this helps.

Rob

Robgrob

Agreed. Buy the ECU, use my tune if you want to try it, fine tune the AFR if needed and never think of it again.

There are new versions of the software that are better than my old MSQ version btw. I would strongly recommend them.