mastaflymason

iTrader: (1)

My Megasquirt 1 V3 won't start, and I think it has a problem to do with the board itself. My car is a 1996, and I believe that this is wired for a 1.6 fuel pump. I bought it from a forum member (supposedly brain built) and it was supposed to be for a 1996.
http://imgur.com/A6qx8,Az3Rs,y7goy,uyKNu
http://imgur.com/A6qx8,Az3Rs,y7goy,uyKNu#1
http://imgur.com/A6qx8,Az3Rs,y7goy,uyKNu#2
http://imgur.com/A6qx8,Az3Rs,y7goy,uyKNu#3

My harness is sketchy looking, but it holds up fine and it is hooked up based on the diagram on the wiki for the 96. Does this board look okay for a 96 standalone? The wiring harness had the 12 volt going to the fuel pump, so I took it off and hooked the fuel pump wire to it. Now the car won't start, and I think it is because it isn't set up for a 1.8. Is there anything I have to do to the board to get it running?

Thanks!

Joe Perez

iTrader: (8)

1: I'm confused. What do you have connected to pin 1U (light green) at the car's ECU connector? This is the fuel pump lead, and on a '96, it expects a closure to ground. (I can't really tell what's what from the pics of the ECU connector provided. Also, without being judgemental, that wiring looks kinda iffy.)

2: Do you see an RPM indication in TunerStudio while cranking?

3: Have you tried jumpering the FP wire to GND within the diagnostic connector (under hood) to eliminate the fuel pump wiring as a possible fault candidate?

mastaflymason

iTrader: (1)

It is connected to pin 37 on the DB37, which is for the fuel pump I believe. For whatever reason the harness originally had the fuel pump coming from pin 4 I think from the DB37.

I do see an RPM indication on Tunerstudio.

I have not, but I will try that tomorrow. I was just wondering if the board and harness looked OK, because I had to change it the fuel pump ---- around.

mastaflymason

iTrader: (1)

And one more thing. According to this: http://miataturbo.wikidot.com/ms-mods

"You MUST remove ST_Sig fuse under the hood or you will burn up the transistor!!!"

If it was set up to drive the 1.6 fuel pump, which I believe it was. Have I burned up a transistor somewhere? It seems as this was set up for a 1.6? Maybe i'm wrong though.

Joe Perez

iTrader: (8)

Pin 3, judging from the picture.

With the 1.6 cars, the fuel pump isn't normally driven from the ECU. So we cheat by shoving +12 down the wire which normally senses whether the starter is active. I suspect that's what the transistor-with-the-resistor-on-top is doing at the end of the heatsink. (Can't quite figure out why it seems to only be wired to an IAC pin and a SPR pin, but not FP. Maybe there was an external jumper?)

At any rate, the FP portion of your board looks intact to me. Basically just R16, Q2 and R40, plus a couple support parts for current-limiting. I suspect that part of the circuit is fine.

Perchance, are you seeing normal operation of the TPS in TunerStudio? I'm wondering if the ECU doesn't think you're in flood-clear mode. A datalog would be helpful.





That's only relevant to the modification done for 1.6 cars to output +12 for the FP circuit.

Braineack

iTrader: (62)

Braineack built MS with butchered harness.


The EASIEST solution pin 37 to 2O. This brings the FP ground to the AFM connector. then in the AFM connector, you can jump the 2O pin to the pin normally used to trigger the fuel pump relay.

This only works if you are using the GM AIT sensor and have the AFM unplugged. Otherwise if the AFM is being used, you don't have to worry about pin37 at all.

mastaflymason

iTrader: (1)

So my setup should work as-is as long as I keep my AFM? I haven't taken it out yet, but I do have the AFM sensor, I just hadn't planned on hooking it up yet. Maybe I'll try reflashing the firmware.

Braineack

iTrader: (62)

well you have a 96, so I'm spouting worhtless info for you. caus ei dont read.


pin37 needs to connect to 1U.

Joe Perez

iTrader: (8)

He already verified that (post 6).

Assuming nothing is broken, the fuel pump really ought to be running.

Here's a test: Find a quiet spot. Get in the car and connect laptop to MS. Turn the key to ON (but not to START) while watching the screen and listening. You should see the "Fuel Pump" indicator in the bottom-left of the screen turn green for two seconds, and at the same time, hear the fuel pump run and then stop.


But I'm thinking that something other than the fuel pump may be at fault here.