Here is a problem that I have fought for almost two
years. My 2001 Buick Regal will not start after a
shutdown and heat soak. The car has 128,000 miles, never
shuts down while driving, and starts and runs perfectly
in the morning. When it wonít restart, you can crank
it until the battery runs down but the car wonít
start. After shutting the engine off, it will start
immediately ó if you donít wait too long!
operating temperature is normal; it never overheats and
has a new thermostat and ECT sensor. There are no intake
manifold leaks, either vacuum or coolant. Fuel pressure
is normal but a new regulator was installed along with a
new MAF sensor. In a no-start condition the spark will
jump a gap of at least one inch at the coil.
the summer I carry a jug of water in the trunk (in
winter I use snow) and in a no-start condition I pour
about a quart of water on the intake plenum. The car
will start right away and will run perfectly until the
next no-start condition.
I canít recall a better description of vapor lock. The
proper term is fuel percolation, which describes
residual engine heat boiling the ready fuel supply in
the fuel rails near the plenum/intake manifold. When
this occurs, fuel pressure fades due to the aerated fuel
disrupting fuel delivery from the injectors. Even though
fuel pressure may be "normal" when tested with
the engine running, I suspect fuel pressure drops
quickly after shutdown due to percolation.
water to cool the intake stops the percolation. The
first few injector pulses bleed air from the rail and,
as fuel pressure returns, the engine starts.
how to eliminate the problem? Start with three simple
steps. Idle the engine for 30 seconds before shutdown to
allow coolant to carry residual combustion heat from the
cylinder heads into the radiator. Pop the hood open to
the safety catch position to allow hot air to escape
from under the hood. And try different brands of fuel,
looking for a fuel with a vapor pressure less prone to
addition, make sure airflow through the A/C condenser
and radiator is clear and unobstructed. If the cooling
system hasnít been serviced recently, a power flush
might lower coolant and underhood temperatures
to cover all the bases, turn the ignition to the
"on" position and listen for the fuel pump to
run for two seconds and then stop, confirming that the
fuel pump relay and fuel pump are operating properly. Iíd
also test for injector pulse widths from the PCM to
confirm that the fuel injectors are being commanded to
open/close on a hot restart.
I have a well-maintained 2003 Acura 3.2L TL-S model with
114,000 miles. My Goodyear dealer has continued to
propose replacement of the timing belt and water pump.
He said the belt should have been replaced at the
seven-year mark or 100,000 miles. I canít seem to find
any definitive recommendations from Acura or on the
Internet about this repair. I want to maintain the car
and continue to drive it for a number of years and would
value your opinion on this repair.
Acuraís service recommendation for this vehicle and
engine, as outlined in my Alldata automotive database,
calls for timing belt replacement at 105,000 miles/84
months under normal operating conditions. Under severe
service conditions ó operation at ambient temperatures
under minus-20 degrees or above 110 ó replacement is
recommended every 60,000 miles.
this engine, a timing belt failure could allow contact
between pistons and valves, resulting in catastrophic
engine failure, so a new timing belt makes perfect
sense. Include pre-emptive replacement of the water