fuel pump and fans
 

are these hard wired connections or software? currently my fans run all the time, but sop with brake application. The fuel pump doesn't run without the AFM in place.

the AFM runs the fuel pump. You have a few ways you can actiavte teh pump from the MS.

sounds like the fans are wired to the wrong pin??

care to expound on the options?

I think it's AC control that appears to be "on" but why does it change with the brake light switch?

1: You can remove the AFM, splice a wire into the Light Green wire that runs from the AFM to the fuel pump relay (aka: circuit-opening relay) next to the steering column, and then run that wire to pin 37 of the MSs connector, which is the dedicated fuel pump relay control.

2: You can remove the AFM, unplug the "ST SIGN" fuse, construct a circuit inside the MS which is tied to the "FP-1" line of the CPU (through R16) but emits +12 rather than a closure to ground on pin 37 when active, and then tie this to the violet wire at position 1C of the ECU connector.


Probably because something is wrong in the wiring. Happens to the best of us. With these older cars especially, it's more and more likely that over the years, some previous owner has tried to wire in some alarm system or cruise control or remote start or whatever and made a total bollocks of the wiring.

how did you wire your fans to come on? I'm trying to go through the wiring to see even how it would be possible.

seems like the best option

I can't find any interruptions/changes in the factory harness.


I didn't wire the header.
the only thing I can think of is whatever is wired to 1R on the harness is live for some reason.

the board appears to be wired correctly. FPump to high in, high out to 1C on the header. When I pull the ST SIG fuse. I still have to open the door on the AFM to get the fuel pump to activate.

Why???????

on the fans

1O (brake light switch) is going to input 1 - in and input 1 -out goes to 1J or the AC relay. That seems wrong.

Likely because at some point you did not pull the ST SIG fuse, installed the MegaSquirt, and blew the high side driver transistor that runs the fuel pump circuit. The transistor is a TIP126, which you can find at Radio Shack, Fry's, Digikey, etc. A TIP125 or TIP127 would also work. Make sure you remove the ST SIG fuse before reinstalling the ECU, or you will blow the transistor again.

<edit>
Sorry, you edited your post with an additional question after I posted my reply.
1Q should be wired to the input side of input 1. This loops a/c command through the main board and out to the a/c relay.

Should be pin 1Q like Queen not 1O like October.

:facepalm: happened at the dyno....

will it still function if I jumper the FP at the AFM?

and
If i just cut the jumper from "input 1" going out to 1J to disable the AC. Will my regular fan still work?

Yes, but if you get in an accident and the engine stalls but you are injured or otherwise unable to turn off the ignition, the fuel pump will not shut off. My recommendation, erring on the side of caution, is to fix the high side drive circuit.

You're killing me with the ninja edits man. ;) Yes, the main cooling fan operates independently of the a/c fan. I would remove the wire coming from 1O to the in side of input 1, or desolder the wire at 1O and move it to 1Q.

Does the car not have a/c? If not, another option would be to wire 1J to one of the available outputs and run 2 stage cooling fans.

For now I still have AC.
What's 1Q?

NM, I got back to where I can look it up.

Next question.
seems there is a FI base map in my box. Can I overwrite it with an NA base map?

replacing that transistor fixed it.

Hey gang !

I must have had the ST SIGN 10A fuse and blew the driver for the fuse pump on my PnP

Anybody know off hand what designation that is on the board ?

I was told on the Miata.net board that I need a TIP125TU-ND but I don't want to order until I know where the burnt transistor is or if I am going to have to send it to DIY.... .

Thanks :)

do you have an MSPnP or a DIYPnP?

white or black box?

I wish it was solid white or black.

Mine is the white one with the red plastic that portion that illuminates from the inside.

The board says with the drivers says V3.57.

There are two TP125 drivers. One at Q12 and one at what seems like Q7. None seem fried as far as color etc.

that's an MSPnP
someone else is going to have to answer. I don't know much about them.

Thanks anyway. I appreciate your effort.

Q5 on the adapter board, and it's a ZTX553.