Also, I am having trouble starting this VOLVO and I'm wondering whether
the cause might be electrical, perhaps related to said connector
box/main harness. The engine runs fine once it's is on, but it's very
hard to start -- needs a LOT of cranking, especially when the engine is
cold (it's a little easier when the engine is hot). Could an
electrical problem related to the connector box/main harness have
anything to do with this.
Thanks.
rnott at alexanria. ucsb. edu
The black wire in the plug goes to the Oil Pressure Switch, the Red Wire
goes to the Alternator D+/61 Terminal. After that I forgwt the colors.
One wire goes directly to the starter solenoid (B-Y I think). One wire
goes to the thermal timer--it's in series with the cold start valve. It
allows the cold start valve to inject if the temperature is below 40
degrees and the starter is turning. So I guess one side of the thermal
timer is B-Y and the other is white. The Cold start would be white on
one side and black on the other (grounds on the manifold). The remaiing
wire goes to the Auxilliary air valve and the control pressure
regulator. Both have bimetallic strips that are heated by by switched B+
from the ignition switch--I think the blue wire. The air valve closes
with time and current as does the CPR. Both devices ground under the
same screw on the cold start valve.
To diagnose the hard start you need at least a test light to make some
intelligent guesses. When the motor is spinning and not firing, connect
the test light between the coil negative terminal and ground. If the
light flashes then you have spark to the plugs. Pull a plug and see if
it dry or wet. If it's dry then you are not getting fuel.
Typically long cranking times are due to a loss of rest presure. This
can occur if the fuel pressure accumulator (can next to the main fuel
pump) is leaking or the line pressure regulator o-ring in the fuel
distributor is leaking, or the in tank fuel pump is not working or the
fuel pressure check valve in the main fuel pump is leaking (more
noticeable on hot starts) or there an problem at the air flow pressure
sensor switch (engine vacuum lifts the air flow sensor plate, opens the
switch and allows the fuel pump to run). If you disconnect the plug at
the switch the fuel pumps will run whenever the key is in the run
position. Another common problem is that the Control Pressure regulator
has failed and the control pressure is high. This causes the engine to
be lean although typical symtoms would be a start and stall on intial
start up attempts until the cold start valve stopped firing (usually
three or four attempts) then long crank times and noticeable loss of
power or low power when started. Much like the symptoms of a leaking
fuel accumulator.
If the plug is wet then you are not getting spark. Typical spark
failures are: failure of the distributor pick up coil to send pulses to
the ignition control unit (Often temperature sensitive) or the two wire
lead from the distributor to the two pin connector going to the ignition
control unit). Faulty distributor rotor, bad coil, bad ballast resistor,
or bad ignition coil.
Hope this helps.
Bob
