Megasquirt owners thread

stb · Postby **stb** » Sun Oct 13, 2013 8:33 pm

Hoping someone can help me with a closed loop idle problem (gslender?). I'm running the gslender 2.8 firmware, and can't get a steady idle, especially when warm. When warming up its actually not too bad.

I've got a NB8B motor in a NA, running sequential injection with a NA throttle body and ICV. Fuel is e85, injectors are 2JZ.

I've attached a zip file with the tune and log file if anyone's got a few minutes to have a look for me. I've tried all kinds of PID settings but haven't had any success. It looks like maybe the steps in PWM are too great - a single step of the ICV changes the idle speed by hundreds of RPM. Don't know if there's anything I can do about that.

Thanks in advance,
Simon.

maniac · Postby **maniac** » Mon Oct 21, 2013 8:48 pm

Hi,

I have a megasquirt 3 build by a guy from Miataturbo. I'm having a hard time getting it to work and am at my wits end

Are there any mega squirt experts from here around Sydney who can come help me out?

Adam

Postby **NitroDann** » Mon Oct 21, 2013 9:02 pm

What are you having trouble with?

Dann

maniac · Postby **maniac** » Mon Oct 21, 2013 9:32 pm

It just wont tick over. Think its not getting fuel, but not sure why. Thinking it may be a wiring issue.

I'm getting sick of fiddling with it and just want to take it somewhere to have it done

Adam

Postby **NitroDann** » Mon Oct 21, 2013 9:39 pm

Removed the afm?

Dann

maniac · Postby **maniac** » Mon Oct 21, 2013 9:42 pm

Unplugged but not completely removed.

Adam

Postby **NitroDann** » Mon Oct 21, 2013 9:46 pm

You need to jumper the first 2 pins together to get the fuel pump running.

hold it so where the pins go in it looks like a 'T' and its the leftmost 2, just bridge them.

Dann

maniac · Postby **maniac** » Mon Oct 21, 2013 9:52 pm

Yeah, I've done that

It came with some steps to follow and that was one of them.

Adam

Postby **NitroDann** » Mon Oct 21, 2013 10:05 pm

Does the fuel pump run with the key on?

Dann

maniac · Postby **maniac** » Tue Oct 22, 2013 5:44 am

Just went out and tested it, I cannot hear the pump with the key on. With the stock ECU I can hear it.

Adam

Postby **NitroDann** » Tue Oct 22, 2013 10:58 am

You SHOULDNT be able to hear it with the stock ecu and afm and key in run position.

Dann

maniac · Postby **maniac** » Tue Oct 22, 2013 12:26 pm

Okay, well I have no clue then. I've tried jumping the fuel pump in the diagnostic port too, with no success.

Adam

Postby **NitroDann** » Tue Oct 22, 2013 1:03 pm

You have some issue with getting the fuel pump running.

You need to make sure the pump runs when trying to start the car, consider simply running it from a 12v source and making sure the car starts,m then work your way back to fixing the no pump thing.

The easiest solution would be to simply run the pump on a switch.

Dann

gslender · Postby **gslender** » Tue Oct 22, 2013 2:26 pm

maniac wrote:It just wont tick over. Think its not getting fuel, but not sure why. Thinking it may be a wiring issue.

I'm getting sick of fiddling with it and just want to take it somewhere to have it done

Adam

I know I'm late to the party, but it would help to know what model MX5 you are trying to get this to work on. The early NA6 cars had wiring that requires the ST IGN fuse to be removed and the MegaSquirt wired to power 12V directly to the fuel pump. This is the normal way any MS2 or MS3 should be configured to handle this and common approach is to either run a 12V relay off the ecu fuel pump output pin, or to build a circuit with a FET or similar to drive the pump.

This question should also be directed to the person who built the MS3 board and to confirm what they were planning to ensure the board is suitable for an MX5 of your year and model.

I know this sounds complex, but this is why the MegaSquirt is available in a complete ready to run version (MS3Pro and MSPNP2) for those that don't wish to be mucking around, and a range of DIY kits (DIYPNP/MS2/MS3) for those that understand the electronics, build process and time to get it right.

If you're in the former category and you've got one of the later DIY kits then a mistake has been made (and it will probably cost you more than the difference to fix).

G

maniac · Postby **maniac** » Wed Oct 23, 2013 11:33 pm

The car is a 1993 NA8 with an AVO turbo kit.

I have a decent understanding of what I need to do, but I'm slowly starting to get over it. I will try running the fuel pump off 12v to troubleshoot it.

gslender wrote:
maniac wrote:It just wont tick over. Think its not getting fuel, but not sure why. Thinking it may be a wiring issue.

I'm getting sick of fiddling with it and just want to take it somewhere to have it done

Adam

I know I'm late to the party, but it would help to know what model MX5 you are trying to get this to work on. The early NA6 cars had wiring that requires the ST IGN fuse to be removed and the MegaSquirt wired to power 12V directly to the fuel pump. This is the normal way any MS2 or MS3 should be configured to handle this and common approach is to either run a 12V relay off the ecu fuel pump output pin, or to build a circuit with a FET or similar to drive the pump.

This question should also be directed to the person who built the MS3 board and to confirm what they were planning to ensure the board is suitable for an MX5 of your year and model.

I know this sounds complex, but this is why the MegaSquirt is available in a complete ready to run version (MS3Pro and MSPNP2) for those that don't wish to be mucking around, and a range of DIY kits (DIYPNP/MS2/MS3) for those that understand the electronics, build process and time to get it right.

If you're in the former category and you've got one of the later DIY kits then a mistake has been made (and it will probably cost you more than the difference to fix).

G