EGR stall test question

[fixkick]

if the stall test pass and the vacuum does same , hand applied to the EGR nipple then we need to monitor from this point backwards.

the MODULATOR , defaults to DEAD. this is NORMAL.
this one graphic shows all the rules, to get EGR alive. (control side)

see those 3 Nipples, P (ported vacuum) and Q (what i call queer vacuum) and the B port BARK port.
if there is no CAT on the car, the bark pressure will be near zero.
and this causes, the B port to be dead.
if the B port is dead the MOD is dead. at the Q port.
This graphic shows how this happens.
with a vacuum gauge at the P hose, (disconnected,) if you see full vacuum at P hose, racing engine , this is a working ECU, TB port and VSV valve.
one test and you know the electro vacuum side is ok.
but if there is no back pressure at B the V valve is stuck open and no vacuum ever reaches port Q. and the EGR will be dead , doing any live test.