Hot weather starting reluctance

[Tim McNamara]

My 1990 240 has just started exhibiting some reluctance to start when
it's hot out, either over 90F or 85F if the car has been parked in the
sun. The engine cranks over and over but there's no indication of
trying to start. After three or four attempts it thus far has then
suddenly stared normally.

Prior to this, possibly related, I noticed than once in a while after
starting the car, the idle speed was rather low and most of the idiot
lights would stay of. Bumping the gas pedal turns the idiot lights off
and restore normal idle.

The car runs normally. It gets 24-25 mpg in mixed driving, which has
been the case for the six years I've owned the car. No loss of power,
no stumbling or hesitancy.

I haven't checked for fault codes yet. Any suggestions as to the
possible remedy are much appreciated.

 

[James Sweet]

My 1990 240 has just started exhibiting some reluctance to start when
it's hot out, either over 90F or 85F if the car has been parked in the
sun. The engine cranks over and over but there's no indication of
trying to start. After three or four attempts it thus far has then
suddenly stared normally.

Prior to this, possibly related, I noticed than once in a while after
starting the car, the idle speed was rather low and most of the idiot
lights would stay of. Bumping the gas pedal turns the idiot lights off
and restore normal idle.

The car runs normally. It gets 24-25 mpg in mixed driving, which has
been the case for the six years I've owned the car. No loss of power,
no stumbling or hesitancy.

I haven't checked for fault codes yet. Any suggestions as to the
possible remedy are much appreciated.

Things to check, fuel pump relay and crank angle sensor, either one can
cause temperature dependant no-starts. Check first to see if you have a
spark.

 

[Tim McNamara]

Things to check, fuel pump relay and crank angle sensor, either one
can cause temperature dependant no-starts. Check first to see if you
have a spark.

Thanks. The fuel pumps seem to operate normally, but the crank angle
sensor I haven't checked. ISTR there is a fault code for that; does it
trigger the "check engine" light?

 

[z]

Things to check, fuel pump relay and crank angle sensor, either one can
cause temperature dependant no-starts. Check first to see if you have a
spark.- Hide quoted text -

- Show quoted text -

I always just change the exhaust O2 sensor, then scratch my head in
puzzlement. Worth a try, especially the scratching the head part.