"Mike" <zephyrs_baseball (AT) yahoo (DOT) com> wrote

I have never tried driving the car with the blue/white wire grounded; maybe
you could take the emissions test while it's grounded and your idle is
correct.

Check that the microswitch near the throttle is working
properly (is it clicking when the throttle is closed?) Since the idle is
correct when the blue/white wire is grounded, your base idle setting is ok.

Clean the large grey connectors on the firewall and make sure the wire is
connected to the coolant temperature sensor and that the sensor is working;
it's behind the distributor and below the intake manifold.

If none of the above fixes things I would suspect the ECU. Find one at a
junk yard if you narrow it down to that. You may want to have a shop
diagnose the problem if the ECU is too expensive.

BTW: What engine and fuel injection do you have? I have the Volvo
green/white service manuals but they talk about several years so it would
help if I knew exactly what engine you have.


Brick_0

In article <412750eb.0307051223.648c7d53 (AT) posting (DOT) google.com>,
zephyrs_baseball (AT) yahoo (DOT) com by Mike dropped his wrench, scratched his head
and mumbled,
unit. The coolant temp sensor raises the idle for cold engine conditions.
The higher the resistance the higher the idle. Disconnecting the sensor
shows infinite resistance to the control unit and raises the idle to its'
theoretical limit of 2200 rpm.

The throttle position sensor, or switch in this case, has three
positions. Idle, off idle, or full throttle.

If you pinch off, or plug the idle air bypass hose (running from the
intake bellows to the idle air control valve) you can, with a warmed up
motor, set the idle with the throttle plate, (thumb screw all the way in)
to 850 rpm. Prior to adjusting the throttle plate, slacken the screws on
the throttle switch and rotate it it counter clockwise until it clicks.
Slacken the 8mm AF jam nut on the idle plate stop screw.

With the motor running, remove the aux air supply, adjust the idle speed
down to as low as it will go. If the motor is in decent shape you should
be able to drop the idle to 450 rpm or so. It will be rough as a cob and
barely running, but it will idle there. Lock the jam nut. Reconnect the
aux. air supply. The idle should raise to 7-800 rpm. Trim the idle to
850-900 rpm with the thumb screw.

Recheck that the throttle switch clicks just as you move the throttle
plate off idle by turning the throttle cable spool by hand. There should
be a gap of 1/16" to 3mm between the stop on the throttle spool and the
stop on the bracket. If all is well tighten the throttle switch screws.

If after all this the idle does not conform, replace the throttle switch.
The contacts/wiring inside are finished.

Bob

--
The goal of driving is to miss the maximum possible number of objects.