turbo engine emissions removal
When I refer to emissions removal, I generally get rid of everything on
the engine not needed to run, even though they may not be emissions parts.
Some of these parts can be left in place while others are removed, but
this writeup shows you everything that can be removed while maintaining
the running of the engine. Some users may want to keep the cold idle thermowax
and coolant lines, and/or BAC valve (to help with idle under load). I
find that a healthy engine with properly adjusted idle (I sometimes bump
mine up to 1000 or so) has no problems running normally without this.
You can also remove your oil metering system and run premix at this time
for even more simplicity, but I don’t normally consider this part
of emissions removal.
You’ll need plenty of vacuum caps in sizes 5/32”, º”,
and 3/8”. Also a tube of ultra black sealant or equivalent (permatex),
blockoff plates, 5/16” fuel injection fuel line (about 5 foot),
hose clamps, and a few feet of 5/32” vacuum line and some tees/splitters.
I use jb stick weld, not the liquid kind, but the putty type that you
mix with your fingers, for the holes left in the TB by removing the throttle
plates. Some more paranoid individuals might wanna take the extra time
to tap and use metal plugs instead, though I’ve never had an instance
where the jb weld came out of the hole (I pack it in well, and leave a
lip on each outside edge).
Start off by removing the intercooler and upper intake manifold. Then
remove the vacuum rail and associated parts. For help with this part,
refer to the engine teardown procedures listed elsewhere in the tech section.
The engine should look like this when you’re ready to proceed here.
Go ahead and install your acv
and split air pipe blockoff plates, using new gaskets and/or sealant.
When installing plates, use vise grips (or the double-nut method) to remove
the studs, and use bolts for the plates for a cleaner look. The acv plates
leak very easily, so be sure to seal this one off very well. The upper
lefthand corner is where the leaks occur.
Subzero start valve:
Assuming you’re removing the thermowax and associated coolant lines,
we’ll block off these coolant ports. To do so, I drain the coolant
(obviously). I take the tube of ultra black sealant (this stuff dries
very strong) and inject some into the nipple, enough to penetrate all
the way down. Then I take the large vacuum cap, and inject a little into
it as well. Put the cap on the nipple, and use small hoseclamps to tighten
it down. Don’t refill the coolant for a couple of hours, to give
the sealant time to dry. The sealant is important, the vacuum caps are
not rated for high heat or pressure, but the sealant keeps coolant from
making it’s way to the cap (or much of it, anyway). The cap keeps
the sealant from being pushed out of the nipple, or developing a leak.
I use these on my own cars with no issues, but you may want to check and
replace them about once a year.
Using the small vacuum caps, block off the nipple between the secondary
oil injectors, and the nipple above it on the LIM.
Use one of the º” nipples to block off the unused nipple on the
oil filler neck, unless you wish to keep this connected to the charcoal
canister (which you can do, via the original hose to the firewall). The
upper nipple, by the fill cap, will need to be left vented so that excess
pressure doesn’t build in the crankcase and cause smoke. You may
want to run an oil catch can, or a drain hose to the bottom of the car,
if you get any oil spillage from this vent nipple. Sometimes a turbo with
bad oil seals will allow boost to vent into the oil system, and cause
it to blow out the vent hole. IF you leave the stock vent hose to the
firewall intact at the lower nipple, you can cap off the upper nipple.
Now I install the fuel rails, injectors, and wiring back onto the engine.
Now is a good time to check and clean your injectors, replace grommets
and orings, and check/repair/replace your FUEL PULSATION DAMPNER. There
is a writeup about this on the tech page, this is very important to helping
your car NOT catch fire. As for wiring, you’ll connect all 4 injectors,
the green coolant temp sensor under the alternator, the 02 sensor, the
knock sensor, and the temperature probe under the oil filter. Clean off
one of the mounting pads on the rear rotorhousing with a wire brush or
sandpaper, and clean the wiring harness ground ring, and bolt it down
securely. You may want to run additional grounds to this point as well.
Everything else can hang loose, it won’t be used right now.
Assuming youre keeping your OMP intact, run the 4 oil injector hoses to
the original vacuum splitter (if you didn’t break it, if you did,
use an autozone version) and run a larger hose out from that, about 8”
worth. This needs to go back to it’s original nipple, the largest
of the ones on the back of the UIM.
Go ahead and run new fuel lines. The one from the lower rail will go directly
to the fuel filter, the one from the upper rail/FPR will go right to the
firewall drain connection. You’ll need to use a new hoseclamp on
each end, each hose needs to be about 2-2.5 feet long. Its not a bad idea
to check the hose every 6 months or so for deterioration from heat.
Now, working on the UIM, remove the throttlebody, and all the valves from
the dynamic chamber.
Block off the valves and vacuum ports…
Now, to perform the throttlebody mod (that I perform during emissions
Stock throttlebody, TPS side up, mounted in vise…
Remove the double throttle linkage stuff and dashpot…
Flip it over…stock thermowax side mounted upwards in vise…
Remove the dashpot…
Fast idle cam and spring (you have to remove the throttle stop plate while
holding the throttle pullies back, then remove the snapring, cam and spring,
and replace the throttle stop plate and screw)
Now mount the TB in the vise with the butterflies facing up. Remove the
Top set of butterflies and shaft, and plug the holes with jb weld, leaving
a lip on each outside edge so they can never move. Don’t let a lot
protrude into the intake path.
Now is a good time to pressurize your fuel system and check for leaks.
BEFORE installing the UIM. To do so, put a jumper wire in the yellow check
connector at the passengers side strut tower. Turn on the key and check
the engine bay for fuel leaks.
Reinstall the TB, UIM, intercooler, piping, etc. Connect the intake air
temperature sensor on the TB elbow, and the TPS connector. Don’t
forget to connect the OMP vacuum hose to the back of the UIM (if keeping
it) and the brake booster hose. You now have 3 items that need to see
manifold vacuum/boost, they will all get teed together and run to the
single vacuum nipple left, on the passengers side of the upper intake
manifold…these are fuel pressure regulator (upper fuel rail, back
side), blowoff valve, and boost sensor (if you have a boost gauge you
can tee it in here as well).
Cap off the extra hole on the IC pipe (unless keeping the BAC valve and
Cap off the nipples on the intercooler…
Reconnect your throttle cable and refill the coolant, etc. Fire it up,
you’ll have to adjust your idle when warm. When cold, expect to
have to hold the throttle for the first 30 seconds or a minute until the
engine warms up and will run on it’s own (unless you kept the thermowax
system). Your idle adjustment (unless you kept the BAC) is on the back
side of the throttlebody, under the IC, on top. IN the above pic, if you
look just below the 2 capped nipples, you can see the IC shield plate,
and just under that, the 8mm locknut and flathead setscrew that is your
only idle adjustment.