EDIS runs w/SAW unplugged, dies w/SAW plugged in

[Minami Kotaro]

The Bug starts instantly and easily with the SAW wire unplugged (perfect 10 degrees BTDC) but will not start with it plugged in. If I start the engine with the SAW unplugged and then plug it in, the engine dies.

I did the v2.2 board mods for taking SAW signal from LED 17 according to the instructions at megasquirt.sf.net/extra. MegaTune is set to the parameters listed there, as well.

The troubleshooting guide doesn't mention this particular problem and a search didn't turn up anything.

EDIT: Ok ... when the SAW wire is plugged in, the fuel pump shuts off when I crank. The fuel pump will run when I turn the ignition to "ON", but as soon as I turn it over to crank, it stops running and does not start running until I let it go back to "ON". However, when the SAW wire is unplugged, the fuel pump continues to run during cranking.

WTF?

EDIT 2: I used the board mods on the main page (remove D5, D8, R10, etc.). However, I see now a link for EDIS4 for "old users using the old wiring". That is completely different. Is that what I should have used?

[Minami Kotaro]

Ok, on the board mod instructions, it says to run a wire from the bottom of R10 to the right (banded side) of D9. Am I supposed to also remove D9?

I can't find any other problems with the EDIS wiring harness or with my board mods.

[jsmcortina]

Check the external wiring of your SAW wire - it sounds like you have it connected to +12v or something?

Regarding the "old user" thing. This doesn't refer to your age, it is whether you wired your board three years ago with the very first incarnation of the MegasquirtnEDIS firmware. I've updated the webpage.

James

[Minami Kotaro]

Check the external wiring of your SAW wire - it sounds like you have it connected to +12v or something?James

That certainly seems to be the case. When the SAW wire is plugged in, it appears to be cycling the main power relay along with the ignition.

I.e., the fuel pump and MS unit switch on and off along with the ignition pulses.

[Minami Kotaro]

Further weirdness:

Dad redid the shield wire on the EDIS harness. It will run now with the SAW wire in BUT it will not run with the laptop unplugged from the MegaSquirt.

I think I'm going to give up and order a preassembled v3 MegaSquirt.

[renns]

I think I'm going to give up and order a preassembled v3 MegaSquirt.

That won't solve the problem if your harness is the issue. Take some time and check each connection on the DB37 end of the harness.

Roger.

[Minami Kotaro]

Dad and I went through the board. We found a couple of bad solders. All the DB37 and DB9 connections are good.

Must be the SAW wire getting crossed with the +12v switched wire in the EDIS pigtail.