Question from the M25 hard shoulder..
 

As I wait for the AA to turn up, I thought I'd try and figure out why I'm sat here.

Car is a 93 WRX, symptoms are random loss of power (I.e. Engine turning off) regardless of speed. Car then restarts and idles fine after sitting for 10 minutes, then shuts down again after twenty seconds.

Changed the fuel pump two weeks ago and have done 200 miles since, changed the air filter and cleaned the MAF (both of which were filthy and so the car was running so much better as a result) and have done 100 miles since then.

Last drive before this one, the turbo melted the boost gauge pipe, which I've trimmed and blanked off with a self-tapping screw whilst I wait for a replacement. Before that (100 mile) drive, I removed the VTA DV to try and find an appropriately-sized bung to blank it, but couldn't do just put it back on for the time being - not sure if either are related?

Strangely, the boost gauge was (obviously) reading a vacuum once the pipe melted, but after this (fateful) drive, it reads slightly less vacuum...despite not being hooked up to anything.

Any ideas would be great! I'm guessing it's fuelling related? Fuel pump primes on ignition.

Thanks in advance!

Just to update this, in case anyone is searching for the same symptoms, on further inspection the fuel pump only appears to work sporadically. Assuming the new Walbro isn't a dud, I'm guessing my wiring is to blame.

Quite often the wiring connector under the back seat for the fuel pump

Thanks - I'll check that.

It seems to prime fine, and fire up using the fuel that has been primed, but the fuel pump doesn't run whilst cranking or once the engine has fired. Strange.

Is your alarm/immobiliser wired into fuel pump? It's an issue on sigma alarm systems on later classics but not sure early classics had sigma alarms?

I looked into that, but drew a blank. It turned out that a solder on the wiring to the fuel pump inside the tank had snapped. The wires were resting against each other, causing the intermittent running.