ok so here's the rundown

car has been running strong up unitl a few days ago. for some reason or another the car will not tip-in or have any low rpm throttle once it hits secondaries which is an event unto itself.(lots of stumble and fumble it doesnt drop out entirely)

assumed it was the P injectors and found the car had been running on LI injectors for the year that Ive owned it(came with the car) without an resistor pack. S injectors were low inpedence so no big deal.(also swapped the ecu with a known good one just in case)

problem stills persists

since then Ive checke every electronic device on the car that influences fuel delivery to no avail.

fuel pump: swapped it to an FD pump X
fuel lines and filter. changed filter lines were good X
checked AFM: good IAW the FSM
checked reg: havent done tht yet but as i said, the car does fine above 3700rpm
TPS: good
primary injectors: metered good . they spray fuel (did the mazda "poor man's flow test") still weary will probably replace.
checked harness: continuity to inj., coils, inj.12v and all sensors is good
grounds: good but redid them anyway. all meter less then 1ohm.

tested SAFC that was installed and has functioned properly for about a year now: tested good with proper setting and set to zero correction for testing and diagnosis purposes.

tested for possible vacuum leaks or mechanical failures: non so far

my only guess now is the regulator has crapped out or there is an electrical problem that eludes me.(ignition system?)

any insight would be appreciated

1988 s4 N/a
third bridge
fd fuel pump
oem primaries 550cc secondaries
sequential ignition mod
no pulse damper
no emission equip.

ps if this a re-thread i apologize in advance. my internet crapped as i attempted the first version of this thread.

 

update:

fuel lines blown and rechecked w/ pressure gauge.


wont go over 40lbs. range is about 32-38 lbs at throttle

ttt

 

what do you mean "3rd bridge",???

 

aux ports have been b-ported. basically a large street with the aux b-ported as well. not something I did but it has been confirmed done to what was described to me.