cold idle problem, 1993 245

My wife's new-to-her 1993 245 has shown a cold weather idling problem
(e.g., around 0F). It lopes and surges while idling, dying
frequently. This persists for a good half an hour or so, long after
the engine has reached normal operating temperature, although the
problem does get progressively less prominent as the engine warms up.

Thus far the injectors and O2 sensor have been replaced, and the idle
control valve was replaced yesterday without fixing the problem. So
obviously the source of the problem has not yet been identified.
Suggestions are very much welcome!

Frankly I think the mechanics my wife uses are incompetent- nice guys,
but this sort of repeated "we'll try this and see if that works"
approach is their norm and gets very expensive. This isn't the first
car of hers for which serial repairs seems to have been the strategy.

Thanks and a happy <insert appropriate holiday> to you all!

 

Hi Tim - here are my two guesses: a) a failing AMM, or b) a failing
radio suppression relay (maybe all it needs is for the contacts to
be cleaned).

Happy holidays,
Beverly

 

The usual cause of cold idle problems is gunk in the throttle body, although
it's just as well the idle air control valve was replaced. The throttle body
can be cleaned on the engine, but removal to do it thoroughly is worth the
modest labor. The idle passage on the bottom of the throttle body, where
that big thumbscrew is supposed to adjust the bypass air around the throttle
plate, is probably plugged solid.

Blame the Volvo alternative to PCV, where the crankcase vapors are recycled
ahead of the throttle. It sucks a lot of mist-laden vapors through the
throttle body. Question for the gurus: does Tim's '93 have a flame arrestor
that needs to be cleaned regularly?

Mike

 

Yes I would certainly say look for a new mechanic, I'm surprised they
*replaced* the expensive idle control valve, usually it can be cleaned out
with some carb cleaner and provide years more service. Injectors can be
rebuilt inexpensively too. Has anyone cleaned the throttle body? I usually
remove it and soak it in solvent on high mileage cars. Carb cleaner and a
stiff toothbrush works ok too. Check for vacuum leaks too.

 

Yep, it does, well it did, someone may have removed it but it should be
there. Nice thing about the newer cars is it's up above the intake manifold
where it's easy to get at.

 

Thanks everybody, that gives us somewhere to start:

1. Clean the throttle body
2. Check idle control motor
3. Check for vacuum leaks
4. Check air mass meter
5. Check flame arrestor
6. Check radio suppression relay, if it exists.

Any other ideas will be welcome. I'll be out of town for the next 5
days. Happy holidays!

 

Check the air hose from the mass air flow meter to the throttle body for
leaks($29.00). Is the check engine light on? The OBD code for the O2 sensor
can be triggered by a defective mass air flow meter ($320.00), unplug the
mass air flow and see if the idle clears up. The car will default to a "limp
home mode" and will have no power. Both of these parts are easily replaced
and do not require special tools,

 

my 89 240 had a similar problem when i bought it and it turned out to be a
valve out of adjustment, it had a new headgasket installed and the mechanic put
the wrong adjustment shim in.

mark