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failed smog because of fuel evap leak
#1
I have recently replaced engine on 1995 Sidekick and failed smog test. All emissions were within norm but evap test failed. The test guy told that evap line was leaking. I have not touched eval line when replacing the engine, but I checked the evap canister and all lines and they looked sound. I started looking for possible other causes: checked tank pressure valve by blowing into it - it opens after I blow a little harder, checked voltage on evap canister purge valve - it's zero all the time, can it be the root cause? I also discovered some valve/sensor on the intake that my previous engine doesn't have (pictures are attached         ]). It had a plastic finger which was broken and a hole was there. It sucked air through that hole and engine worked unstable, so I plugged it with a piece of eraser. Can this be the root cause? Thank you!
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#2
so, he did what,remove the gas cap.
then attached his leak down tool / engine off or running????
then saw with his tool or gauge, that your evap system will not hold pressure, that fails. (evap means gas tank venting system)
1995 has no OBD2 so no DTCs for evap here..
this forces them to do the crude tank leak down. cap OFF , (where was cap,? during test)??????????
and is hard to pass.
to find this cause, there are 2 ways, using pressure or VACUUM.

SINCE HE REMOVED THE gas cap and is not set aside, (was it)????

then the cap is not tested. and is top fail here. if he did use your cap, replace it now.... some refuse to test caps by them selves..
wish i knew his steps, and exact point of failure?
your photos are clear but no arrows pointing to your topic.

lets review how 95 works, it's real simple before 1996.

first off, not running engine the evap vsv is closed, and the vsv can not suck the evap tank. (canister activated carbon)
running and moving , VSV is open the vsv sucking the tank
but not parked.
but your smog man can not test this engine side, (not unil 1996) see?
the tank is tested only. at the smog station, and not past the check valve, pressure valve, near tank..(well unless iTS bad, stuck open)


this reg valve is closed. until a large pressure, builds in side tank(cold to hotday), say 1 to2 psi. and then the valve opens and pushes fumes in to canister.
it then collects them. this is why gas caps go whoshhhhh when unscrewed on a hot day. pressure there is normal
the vsv is closed, then when moving fast, the ecu opens the vsv and sucks and burns those collected fumes.
he cant test that ever. in 1995. cant.

if they use vacuum and it fails,(i dont know what he used)
the pressure valve near tank is closed. (as must be)
if the vacuum leak down test fails, its a bad leaking tank or a hose, for sure.
if he used say 1/2 psi ,as some do, so can you, and in most shops they use nitrogen gas at 1/2 psi.
then spray everything, there, near tank. all hoses and fittings.. there...
bingo bubbles, its soap spray like finding natural gas leaks, same spray ,home made

finger?
cant see it?

ask him did you pressure test my system or vacuum test it???????????
if no leaks found (soapy water +pressure)
then block the hose at the forward side of the reg.valve on main evap line near tank.
if the stops the leak, the valve is bad, its passive spring loaded valve , no elecrics there)

finding evap leaks can be easy look for damaged hose, or rusty tank top.

why is your egr hoses all wrong?
that rear, plenum fitting vac, is for 3sp a/t transmission, vacuum modulator , not egr
that will cause egr to be under hard vacuum all time time, very bad... with cat present.
or is that optical illussion for 2d photos. that egr mod valve looks like it going to that brown hard vacuum port.

i may be wrong, no fill flash and too many dark shadows.
http://www.fixkick.com
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#3
tpc in backwards
http://www.fixkick.com/sensors/EVAP/Evap-testing.html


i think my page will help
http://www.fixkick.com
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#4
[Thank you! Some answers to your questions:
1. The tank cap is new and it's attached to the neck. I think he was putting some hose into the tank.
2. The test guy used nitrogen injection.
3. I circled the sensor or valve(?) that I was talking about in my original post.         . Is it "3sp a/t transmission, vacuum modulator"? The donor engine came from the vehicle with automatic tranny. Do I need this vacuum modulator with my 5 speed manual? If I don't what do I do with that port where it's screwed in?

I can call the smog test guy. What specific questions should I ask him?


Thanks again.
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#5
hello and greatings....
sidekick, not tracker ,OK.
1995, OK.
what trans mission, ? 3sp/4sp or 5speed, (keep in mind your engine swap fools me, util i know what you are driving, Drive line)
95 kick, 16valve MPI, some trans, some doors, please answer some)


yes, no CAM fill flash makes shadows. im all wrong, the hoses are correct, it looked all the world the mod was hosed up to a/t port
its not
sorry,
yes, the shops smog remove cap, test cap by self, then set it on a bench
and then pressurize the tank with inert nitrogen, (using air is dangerous in pro shop with gas) 1 spark and boom if air is uses. or a leak of vent air. boom.
safety first.
i use air, im not afraid, and no spark in driveway, and no smokers.
the problem is simple , your vents leak. its just tank, hose and 1 valve. there. one leaks. air. (breached)
you failed the vent leak down tests.

that photo to is only for the 3speed , only. if you dont have a 3speed,, then it sucks are, bad that real bad, lean engine.. good way to burn valve.s
THE 3SP CAR MODULATOR HAS NO RELATION SHIP TO EGR MODULATOR. AT ALL, (One uses hard vacuum ,, egr uses smart ported vacuum and uses its own ports)


the egr is mandatory, if it is connected wrong you get code 51 (usa, only) and fail instantly. (huge numbers of causes)
what matters are tank vents.
have you looked under rear fender wells. with flash light for top of tank rust or hose damage on both sides
to do that magic, jack rear body only not axle, the body rises and not tires, making the view over top of tires more easy.

am still at loss where you put and eraser.
did you put a 3speed engine in 5speed car or 4speed? (no problem but needs changes)

tire view right
http://www.fixkick.com/INJECTORS/PUMP/pu...tview1.JPG


see cave in
see all those, non fuel lines, those are called vents.
and they just not leak.
finding leaks here,takes hard work.
even dropping the tank and pressure testing all and or simple inspection.... omg rust , omg hose is like gram-crackers. leaks like sieve.
and more,, all parts (not fuel) are suspect. its and air tight system on all cars. and if leaks, you fail smog,
in some states .) this test1, and the testing ends. why go farther.?
see raw fuel leaks there, damp rings on top ,wet./????
find a shop that can fix this,

id crawl under, ever been there? just in front of tank, huge space there,
then inspect. this is like 1st deal
even loose clamp..... found. or? over 20 things that can leak on top of tank, its full of seals and hoses.

or this bad
http://www.fixkick.com/sensors/EVAP/PRV.jpg


or make your own pressure tester and use soap spray
there is no other ways, (unless you can do vacuum tested, but vacuum sucks and makes no bubbles. so takes sonic vacuum leak detecting tool)
unless super lucky and can shake car hard, parked, and see hoses or seals, go wet. top of tank.
luck happens.


http://www.fixkick.com/sensors/EVAP/Evap-testing.html
http://www.fixkick.com
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