8VALVE NORMALLY ASPIRATED
Page designed and maintained by Dana Arenius . Dedicated to those who are maintaining/driving these everyday and want to know their
way around the car a bit more. It may help to communicate with or understand your mechanic as to what may have been wrong. It may also help
the self motivated with the proper repair manuals.
-
HORSEPOWER
110 CYLINDERS
4 INJECTION
BOSCH MECHANICAL
-
Power rack and pinion steering,
Power dual diagonal disk brakes, front wheel drive, non-turbo
This engine has 169K miles on it (it's
still a baby). Mostly all orginal parts with the exception of the
battery, water pump, idler pulley, two gas injection lines, and master
brake cylinder, brake pads, muffers, crankshaft seals, and of course clutch
work.
-
Features:
Looking at the engine from the drivers side. Mechanical fuel distributor
with four injection
lines coming out (bottom center). Oil fill (red cap). Oil filter (just to the bottom right of red cap). AC
compressor (top right). Air intake rubber bellows (bottom left). Intake manifold with "angled" cold start
fuel injector (center). Warmup regulator and auxillary air valve (top left). Cooling water expansion tank
(yellow, bottom right) One of the big items is to make sure that all those vacuum lines have NO LEAKS
into the intake manifold.
Engine Photo Looking from Passengers Side
-
Features:
Positive crankcase ventilation hose connection from valve cover to intake
manifold
(center bottom). Four mechanical fuel injectors into intake manifold (Yellow lines). Cold start
thermo time switch (between 2nd and 3rd injector with cable/plug on top). Idle increasing valve
for AC operation (above #4 injector with red/black wiring) You will notice that I try to apply hose
clamps where I can to stop air leaks......
Those mechanical fuel injectors
can leak. When you shutdown the car for the night, the fuel system
is
still pressurized.
If they are leaking, you may smell a little gas in the morning and the
car may be
difficult to start if gas
weeped (flooded) into the intake manifold overnight. You will find
the plugs
very wet and you may have
had to floor the petal to get enough air into the intake to start the engine.
Photos showing the cold injector on the left and Electronic Control Unit(ECU) on the right
maximum of 9 seconds (9 seconds at -20F down to 0 seconds at 113F) to give the engine a little more gas enrichment
if the car engine is below 64F. If the care starts in that time and if the engine is still below 77F, the cold injector
valve can be activated by the "pressure impulse switch". The pressure impulse switch (located just under the fuel
filter) senses a high motor load or accelertion condition (by a higher than normal pressure in the intake manifold).
It has a small vacuum line which connects to the intake manifold. Each time the impulse switch senses high manifold
pressure when the engine is below 77F the cold injector is activated. After the engine warms above 77F, the cold
injector valve is no longer activated by the impulse switch. When the impulse switch senses a high manifold pressure
this time, it activates a 2 minute timing relay which enriches the mixture by increasing the amount of time which the
fuel control pressure "modulating" valve is open. At the end of 2 minutes the timing relay is reset until the impulse
switch triggers it again.
If you find that your 85 8V starts up fine
and runs fine for about 2 minutes, then it starts to
oscillate in RPMs from 1000 to 300 (almost
stall) for a number of minutes and then it runs fine, you may
want to take a look at two temperature
switches listed below (which control the cold injector) to see if they
have failed
"open" or are malfunctioning.
The cold injector has a 12VDC molded connector
on top. It is activated by two series connected "temperature"
switches which connect the negative terminal
of the injector to the car body. One of these temperature switches
is located below the water thermosat housing
(2 green wires, closes below 64F, opens above 77F)...the other is a
thermo time switch between the 2nd and
3rd cylinder fuel injector (see picture above). This "thermo-switch"
is special
in
that it has built-in two electrical heaters
(40 ohms resistance between the connector pins and 40 ohms from one
connector pin
to engine, other pin to engine is a temperature
switch which opens above 113F) Ethier the internal
heater(s) warming
time
period or engine termperature can open
the switch as you crank the car over or as car warms.
Thus the cold
injector is thus
"timed" or operated by temperature.....deactivating
the cold injector. The electric power
for the heaters comes from
the starter
motor. So basically, the thermo time
switch is a time limit that cold injection is
allowed while cranking the
engine without
the engine starting.....My experience has
been that the 64F/77F temperature
switch (under the water thermosat housing)
had
failed on me and the warmup idle oscillated
up and down. This
particulair failure can seem random to the driver.
The car AND the weather had to be cold
to see it.
The ECU (electronic control module) in the
right picture recieves electronic pulses from the ignition distributor
"hall effect transducer". These pulses tell the ECU when to connect the
negative side of the ignition coil to the car
body...thus firing
the plugs. This is the device (along
with the hall effect transducer) which can cause the car to "die"
after
the
devices warm up. One may think it
is the car warming that causes the failure. Actually the internal
electronic
components
are heating as it "power switches" the
ignition coil. Ignition coil failures sometimes do not appear
until the coil is up to operating temperature.
If you do not see your tach working as you try to start the car,
the ECU, hall effect transducer , or ignition
coil is a good place to start looking. If any of these fail, you
may
even be able to let the "engine" cool down
and the car may restart. But soon as the components warm up again,
the car may stall again. This may
continue until the component dies completely. One must not also rule
out the
possibility
of a wire connection problem. Especially
the hall effect transducer wiring into the side of the distributor.
and the warmup auxillay air valve on the right (two hose clamps)
-
Features: The warmup regulator
has two fuel lines connected to it. It monitors engine
temperature and when cold...decreases the gas fuel control pressure of the Bosch fuel distributor
to enrich the amount of fuel injection. For my 85, 8V engine, the control back pressure would be
about 17 PSIG at 50F and 33 PSIG at 104F. The relationship between engine temperature and
pressure is linear so one could graph it out for other temperatures. Those two small "hoses"
are filled with gasoline. If you have problems with the car running rough when cold, it is a good
idea to take a look at the warmup regulator (control line pressure with a gauge). It is important to know
that the control pressure values vary for the Model and Year of the car.
The auxillary air valve on the right is
one of two air intake "increasing" valves which bypass
around the throttle plate of the intake.
(The other is the AC idle increasing valve which is
activated when the AC in turned on and
the AC clutch is activated on termperature) One can
just barely see the AC idle increasing
valve in the bottom right hand corner. You can see a better
picture of it below. Both open just
a little and when they are, they increase the engine speed
slightly. The purpose of it is to keep
the engine running smoothly when the engine is warming
or when it is suddenly loaded with the
AC.
When the engine is first started, the auxillary
air valve opens to allow a measured amount
of air to bypass the intake throttle plate...this
increases the engine speed (to approx 1000-1100 rpm)
as the engine warms. An electrical
connector on top powers an internal 40 ohm heater with
12VDC. The heater will cause the
the valve to close again....reducing\the idle back down to 875
RPM. The auxillary air valve can become
"sticky"with dirt and age. You can take the two hoses off
and see a little hole right thru it when
the car is off and the auxillary air valve is cool. I periodically
spray Gum Out to clean the "sliding" plates
inside and tauxillary valve has cooled down and then a
little WD40. I also check the resistance
of the internal heater and check to see for applied 12VDC when
the car starts.
Photos: Left picture shows
AC idle increasing valve (lower left, 3way hose with red/black wires on
top) It is activated
when AC is turned on to increase RPMS slightly
to avoid "dropping the rpms when the AC compressor kicks in". You
can follow
the hoses and you will find in parallel
with the auxillary air valve, both bypassing around the intake throttle.
It should "maintain"
the RPMS as it was before the AC kicked
in. If you find that the engine RPMs drop dramatically and
the car wants to go down to about 500 RPM
each time the AC "kicks" in, this is one of the things you want to look
at.
Unlike the auxillary air valve, it does
not have an internal heater. Just the 12VDC connector on top.
You can check for
voltage
during the time you know the AC clutch
is active. I also clean out this valve periodically.
The center picture shows the O2 sensor.
Change it every 60K miles. This is the single black wire lead type
(no internal
heater which is a 3 wire, 2 whites for
the heater). It outputs a 0-1VDC signal to an emission control
box under the back
seat for measuring the amount of oxygen
in the exhaust gas. The fuel pressure "modulating" valve in the right
picture is
controlled
by the emission control box to correct
the amount of oxygen in the exhaust. You can hear the modulating
valve
"buzzing" as it turns
"off" then "on" each 1/70 of a second.
The more the valve is activated (on) during that 1/70 of a
second, the
further it reduces the fueldistributor control gasoline pressure and enriches
the fuel mixture (less O2 exhaust).
For this car, the valve is open
(activated) 50%
of each 1/70 second time period during
warm idling. Like the warmup
regulator, there is gasoline in those
hoses connecting to the valve.
With everthing working on the car (O2 sensor,
no leaks, etc.)
that about .5 VDC out of the O2 sensor while it is connected.
I.E. the control box under the back seat is controlling.
Photo: Photo showing intake
throttle housing. Microswitch at left deactivates AC clutch when
engine is at full throttle position.
Throttle plate stop screw (just to the right of the microswitch)
and lock nut sets the minimum amount the
throttle plate is allowed to be closed. Usual adjustment
is the point where screw head just touches
the throttle cam arm plus an addition 1/3 turn more clockwise.
Once the car is warm, idle is set by the
horizontal idle adjustment screw (just below the cold injector) to
875 RPM in neutral gear and with the distributor
vacuum advance plugged.. I like to remove the idle
screw from time to time. There is
a small port passage which runs from the idle screw cavity toward the
rubber intake bellows that I like to sray
out with Gum Out. On the opposite side of the cold injector
is the throttle position switch.
With the throttle stop screw set above, the throttle position switch is
set so
that any opening movement of the throttle
plate will activate the lower switch setting. You can hear
the switch "click" when you start
to move the throttle cam linkage.
Disclaimer: This website
is for personal use only. The website and its author are not associated
with or represent SAAB
nor anyother businesses or individuals mentioned
herein. Like most complicated and complex things today, this web
page
can not begin tocompletely
cover all the possiblities which may cause
a problem.
Comments or Questions are welcome.....please e-mail me at .........darenius@aol.com
Hope you enjoyed the site.
OTHER WEB LINKS
-
and if you like sailing:
California
Cape Dory Owners Assoication