74 1.8 - fuel pressure regulator?, opinions. Options

[wonkipop]

car = 74 1.8 L jet (all intact).

problem =
out driving this morning - gradual then worse loss of power. no accelerator response.
pulled over. cut out. no idle. let it sit for a few minutes. restarted it. got it going.
got up road all right, but symptoms kept coming back, then going away. limped it home.
fun ruined for driving, but fun diagnosing started.

felt like your classic fuel starvation.

background. car has been recommissioned and back on road for about 5 months.
running beautifully.
fuel system entirely rebuilt. clean tank. new fuel lines. new fuel pump. new injectors.
all vacuum lines renewed. all ignition compenents renewed. except coil (which could be original, looks like it, but coil was tested and was a goody).

one thing = fuel smell in engine bay on lhs around air cleaner. comes after a few days sitting. had put this down to saturated charcoal cannister, feeding back fumes into aircleaner. have inspected all fuel lines etc thoroughly and no signs of any external fuel leaks/wetness. just a vapour smell thats not there all the time, just after sitting.

pulled everything apart today down there after getting home today.
checked everything. all tight, no air leaks. no bad hoses.

looked at pressure regulator. which sits right there under aircleaner.
i have no reason to think its not original and about 45+ years old.
and did not get replaced. looks great externally, but.........internally?

will get car into shop this week. where i can get some guages on it etc.
at home with car. nothing but basic tools.

but whats thoughts out there.
anyone had this one before.

[wonkipop]

doing the check up one step at a time.

got the car to the workshop today, got there without power loss, but the idle was hunting, not badly, just 850 - 950 on the tacho. up and down. it cut out once at the lights just as i got to the workshop after a 20 minute drive.

we hooked up guages to the fuel system. did a pressure and delivery check.
pressure gauge on the injector side of the pressure regulator.
fuel flow on the outboard side of the pressure regulator.

eliminated fuel pressure and flow as well as pump and pressure regulator from equation.

pump gives 39-40 psi, no vacuum - measured with gauge in front of regulator.

delivers 850ml in 30 seconds after the regulator.

we get 32 psi at 18 inches of vacuum.
35 psi at idle with airflow meter on.
30 psi at 3000 revs.

we figured the hunting was a sign of an incorrect mixture.
reset the points, they were a bit dirty, but not overly. i mean i used to run VWs in the 80s on worse, way worse actually, but we cleaned them and reset the timing.

adjusted the idle to about 1000 just to give it a bit more.

wriggled and moved every single vacuum line and could not make it change idle or react.

then i went out and thrashed it by the railway lines for about an hour.
fun. redlining 2 gear and 3 gear. have not done that for a while. not that a 1.8 is going to give you whiplash, but it was very pleasurable winding it out. was thinking wouldn't it be nice if that was a 917 motor i was hearing. (IMG:style_emoticons/default/smile.gif)

i could not upset it and make it do what it did yesterday.

drove it back home at days end without incident.
seemed to make everyones day in post covid lockdown peak traffic.
folks were waving at me. i was thinking the car was on fire.
they were just waving.

so something upset it, and i can't believe it would be the points.

one step at a time.

we have eliminated the fuel system and the spark delivery.
the coil seems fine, despite its age.

we will move on to more electronic items like sensors.
have to wait for it to come back.