Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

and sends tons more fuel to the engine. See Symptoms. And if it's an intermittent
problem, your engine can be running fine and then go into gas overload 5 seconds
later. And vice-versa. I helped fix a problem in a '90 non-turbo with terrible
intermittent flooding. We found one connector in the sensor plug had "loosened" so
when the plug was pushed onto the sensor, the connector got pushed back up the
plastic housing and sorta dangled freely -- one second it touched, the next it didn't. It
took hours to zero in on this tiny failing. See more at Diagnosing ECT Failures
Cold Start, Dies; Dirty or Faulty IAC. [Symptoms:] Cold Start: Car starts immediately
with no throttle application, idles smoothly for about one second, then hesitates and
dies. Ditto for my 1990 245DL. Starts up cold for one second, then dies. Sometimes,
all cranking I wish to do will not restart
it. If I sit and wait about 5 minutes, it will
start and run like a kitten, with no
problems. I have replaced all spark
plugs, s.p cables, rotor, cap. If it is a
computer problem, can I fix it?
[Suggestions:] Check the IAC (idle air
control- This provides for more air, or
Idle Air Control (IAC) Valve
faster idle on start up. The fact that it
starts readily when cold indicates the
cold start injector is working properly.
See hints below.
[Symptom:] Poor idle. [Diagnosis:]
Clean the dirty Idle Air Control Valve
(IAC). I should have remembered. The
car did not start at ALL. So, I took out,
removed the two hoses and cleaned it by spraying it with engine grease remover. It
had a lot of dirt in it. The Idle Air Control Valve is located under the intake manifold;
below the second cylinder. It is about 3 inches long and about 1.5 inches in diameter (I
do not have one next to me so these dimensions are from my memory.) It has two
rubber hoses connected to it through a "T" connection. It also has a snap-on electrical
plug. This is most likely your problem. Here is how I clean it:
❍ Remove all hoses and electrical connector, then remove the IAC
❍ Open the rotating valve to expose the innards. Spray some carburettor or
fuel injector cleaner into the opening and shake it around. Make sure you
plug the other end with your palm to trap the liquid inside the IAC.
❍ Open and close the flapper valve with a small screw driver to loosen any
dirt, etc. contained inside. Don't scratch the valve