Evap system workaround help

[CostaRicaYJ]

Hello, on my 89 yj 2.5L the evap canister has been removed and I have some high idle issues (1500rpm) I have traced the lines as per attached photo. I have several lines plugged off and a few just open to atmosphere and the pcv line is sucking air like crazy if I plug it with my finger the engine dies. I’m wondering if anyone on here knows a work around to connect what lines together or change what I have going on now to run better. As per first pic “green arrow” port (goes to pcv)sucking air . Port below that open but no vac (at idle) pcv valve is new. How can I make this work without the evap canister as a replacement is non existent in Costa Rica . Second pic is my line rooting I’ve traced ( sorry for the crude dirty pic) Third pic is what I’m referencing

 

[deadpool1]

welcome to MAP based "SPEED Density" EFI injection systems, (loved)
any vacuum leak you make causes high RPM and matching FULL POWER< never a leaning fuel out. OK> (loved)
is the engine bay still stock (per FSM)? no engine swaps or injection modes , carb/TBI'/MPI?????? bingo for TBI !
stock distributor,. sorry
my answers are for what to do on a stock engine only and missing canister. (evap carbon pit/tank)

I will quote you and answer in italics.+bold
Hello, on my 89 yj 2.5L the evap canister has been removed and I have some high idle issues (1500rpm)
well the vacuum line that went to the canister must be plugged up. so it can not now suck illegal air.
all leaks of air the MAP detects and ECU mixes fuel to air , perfectly,


I have traced the lines as per attached photo.
I have several lines plugged off and a few just open to atmosphere and the pcv line is sucking air like crazy if I plug it with my finger the engine dies.
( this means there are 2 problems not just a missing or lost canister)

well that means the IAC IS 100% dead, for sure. (the idle air (speed) controller (IAC/ISC is the ASE names ) ISA is real name this year only.
the ECU controls the ISA, we all know this old system loves to fail and very very hard to fix. (ISA motors?)
put the PCV hoses, et-al', back as it was new. do not mess up or break the PCV system.


I’m wondering if anyone on here knows a work around to connect what lines together or change what I have going on now to run better.
The ISA must be tested and made fully working
I have buddy, that could not get his ISA repaired, at all so he dash mounted, (hack) that is a vacuum hand valve that sets startup air and running air.
to the plenum vacuum port. (i told him to do this at 100% wits end , no parts sold this car his ,old ,1988)
HERE IS HOPING ISA WORKS AFTER YOU BLOCK ALL THOSE ILLEGAL VACUUM LEAKS, ( leaks are not allowed, uness from ISA OR your right foot)
the 0.050' orifice leaks are not an issue, PVC or evap)

if he closes the valve the engine floods and stalls, due to no air at all inducted to the engine. (hand valve hack)
so he has memorized the knob turns to start a cold engine and warm.
it starts and when warm it closes the valve a bit until 800 hot rpm and drives.like that.
I and not telling you to do that, just shows 2 things, how ISA works and at wits end, ISA IS NOW DEAD AND not sold or too expensive to buy.
but first we prove it is bad not guess.


As per first pic “green arrow” port (goes to pcv)sucking air . NO it sucks fumes off the crankcase not raw air ever and most not be modified.
put it back to stock connections. (except last words below)


How can I make this work without the evap canister as a replacement is non existent in Costa Rica .
Evap is super easy to defeat, just find the evap vacuum port on the left drivers side of the engine,intake man)


Second pic is my line rooting I’ve traced ( sorry for the crude dirty pic) Third pic is what I’m referencing

The EVAP CAN has 4 hoses seen below
make sure the tank vent hose is left open tied down, to say fender or fire all so it can breath.
the vacuum hoses CAN, seen as WHITE in FSM , must be blocked, (use screw or Golf tee to do that.

this answer assumes 2 things
routed hoses are all stock now.
IAC works

photo 1, mine from FSM
left to right hose 1,2,34,
block (block means screw inserted blockage or Golf Tee'd
block
open
block
only one hose is open (and free) the tank hose is now the fuel tank free vent.
done, but./..
now the ISA must work.

the TBI system in this car is covered chapter 14, page 22+
the ISA is my topic, if idle controls are now or still dead. learn that vacuum leaks cause the ISA to loose control as all do with excess leaks, VAC.

on this TBI system the IAC is called ISa , idle speed ACTUATOR? << no matter the name is the idle speed control + ECU brains (called a servo)
the ISA is a motor drive device that loves to fail this old, common as nails this fact this old.
C14 page 27 (FSM free manual)
THE AJUSTMENTS IN THE FSM FOR THIS DEVICE IS COMPLEX. i invite you reading the book first on how to do that.

that is all for now.
Yes some parts for this car are crazy hard to source.
for sure new and good.
lots of old bad parts. sure

 

[deadpool1]

c14 page 28
ISA, THE MOTOR PLUNGER EXTENDS NOW
ENGINE OFF KEY OFF
TURN KEY ON B+ RELAY LATCHES UP
AND ECU EXTENDS THE ISA PLUNGER FULLY (SPEC) TO ALLOW PROPER FULL AIR FLOW TO START THE ENGINE
My guess (all EFI) is the the plunger distance varies by engine water temperatures so engine can start cold in Key west or in Alaska both
and both hot and cold starts. as all EFI cars do , IMO
then when started and not running, the ecu controls the idle speeds based off, water temp. when hot most go to 800 RPM and regulate there
even cars with A/T transmission shifting to DRIVE the engine does no stall, the ISA regulates here TOO fully.
only vacuum leaks cause the ISA to fail
or the ISA is actually dead.

FSM.(free)

 

[deadpool1]

the rules are simple (this system)
no vacuum leaks allowed, mostly all leaks are via 2 paths normal the ISA and you right foot throttle valve plate, closed a idle.
the ISA must not be dead, (idle speed motor) if is dead and stuck closed the engine stalls. (no air , it stalls)
0.050 orifice leaks are not leaks (evap or pcv) those are normal. unless the orifices are missing and now a huge VAC leak.
the tank vent at CAN, must now be open to the atmosphere. so fumes can naturally vent, free.
my photo x means blocked. means plug the hose up fully. is best.

does this help?
if not say why ?
also , we can not know if other things are wrong ! on any 30 year old car.
hoses connected wrong , kinked, clogged or cracked or fell off.
the FSM book is free that covers every inch of this. I see you found 1 page called vacuum map.

also learn other sellers of cars like this. with the ISA dead (omg so common this old)
they then cause a new VAC leak, to make engine idle and not stall, and most times they find a vac hose to pull and cause and illegal leak , Illegal means a non- factory mod or alteration of the Jeep design. AKA as a HACK in today's terms.
so there is that too, to deal with when found, none of that I can see , typing here in the blind.