Patchy's Fawlty Towers risk management. Enter at own risk

[StanTheMan]

When you connect a jumper from GND to F/P, it bypassses the relays when ignition is switched on. I can definitely hear it.
It's buzzing away happily.
Disconnect the jumper in the diagnostics box and there is no sign of the fuel pump. No short priming or anything when switching on ignition even when it sat overnight.

I'm not sure if I'm supposed to start the car with the fuelpump bypassing the relays. But it didnt work regardless.

[StanTheMan]

Just read up in it.
It bypasses the AFM not the relays.

Gawd.

[manga_blue]

If you have a timing light then take out all the plugs and get someone else to spin it while you check where the timing mark on the pulley lights up.

[93_Clubman]

Fuel is pumped only upon cranking, so you won't hear the fuel pump when you just turn the ignition key to ON.
That reminds me, the AFM has a fuel cut so that in a crash fuel cuts when air stops passing through the AFM - have you got the AFM fully setup?

[StanTheMan]

If you have a timing light then take out all the plugs and get someone else to spin it while you check where the timing mark on the pulley lights up.

No one around will have to wait. The timing has been set up about the same place as before. It was marked.but will check

Fuel is pumped only upon cranking, so you won't hear the fuel pump when you just turn the ignition key to ON.
That reminds me, the AFM has a fuel cut so that in a crash fuel cuts when air stops passing through the AFM - have you got the AFM fully setup?

Yes I haven't received the Megasquirt yet. I also left the new wide O2 sensor off so if i did have starting issues there would be less chasing & reverting. (It does have an option to send a narrow band signal)

The AFM has been out in the elements although under a plastic sheet on a crate . The electrical connection is on firm 100%
But because it's been outside I'm now a little paranoid. The top has been cracked open and i lost the top about 12 mths ago it's covered with electrical tape. I'm inclined to still look for a new relay . The one under the dash.
They talk about it having 2 coils in the relay on the big forum. http://forum.miata.net/vb/showthread.php?t=245652
I understand the AFM cutting fuel. But don't understand how to fix the issue if that's it.

First though I'll check to make sure I haven't forgotten to take off the plugs on the fuel filter or something.

Tomorrow night is looking good

"Hick" straight Scotch no 5......

Couldn't find any beer

[StanTheMan]

Got a little bored Fuel filter is fine.
Fuel line looks a little dodgy. That will get replaced.

[93_Clubman]

I'm inclined to still look for a new relay . The one under the dash.
I understand the AFM cutting fuel. But don't understand how to fix the issue if that's it.

Agree, it sounds like it's the fuel pump relay, which isn't that common an issue, certainly not as common as the fuel injection relay.
AFM might be an issue, but not necessarily from a fuel cut perspective, that said re AFM fuel cut:

Garrett's book also points out the if you convert to MAP & remove the AFM you'll need to circumvent a safety feature of the AFM which is designed to cut fuel as soon as no air flow is detected. Circumventing this safety feature requires a jumper between pins FC & E1 in the plug connecting to the AFM

miata performance handbook by norm garrett shows the following looking from left to right facing the male plug on the afm:
FC = fuel pump lead
E1 = fuel pump ground
E2 = ground
VC = +5 volts
E2 = ground
VS = air flow signal
THAA = air temp signal
by way of confirmation, the male plug on the afm in the diagram shows two ridges at the top & three ridges at the bottom providing oneway fitting. unfortunately no wire colours are mentioned

[StanTheMan]

this is just a thought.


There was a lot of pressure on that fuel line. Not much fuel came out. But when the pump got activated a shitload came out.

This would mean there is no fuel going back to the tank. It's not moving. It's getting stuck somewhere. Perhaps there is a blockage near the fuel rail?

[Ross]

Double check your fuel lines in the engine bay, then have then check again

[StanTheMan]

Double check your fuel lines in the engine bay, then have then check again

Maybe I should take a pic of how I've connected the lines.

[StanTheMan]

Right line goes to the front of the fuel rail
Left line connects to the fuel pressure regulator.

[smy0003]

Well that's certainly correct.

[Ross]

Ok, i'll shut up now

[StanTheMan]

Ok, i'll shut up now

Why?
No silly idea is silly in this thread. Some of the idiotic things I've done here in the past.
Who's to say some clown previously didn't change something around.At this stage I still don't know which one of those two is actually the return fuel line. One way to find out I guess is put the car on 4 jacks & follow the line from the fuel filter. And have a beer. That would then be not the return line

[ralt]

Hi.
Stan your fuel lines if you have a 1.6 are incorrect. The outlet on the chassis rail at the front connects to the rear and rear to front. Sometimes the experts on here give incorrect advice-sad.