Buick is showing classic symptoms of vapor lock

  • Article by: PAUL BRAND
  • Updated: March 1, 2014 - 12:48 PM

Q: 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, starts and runs perfectly in the morning. When it won’t restart, you can crank it until the battery runs down but the car won’t start. After shutting the engine off it will start immediately — if you don’t wait too long! Engine 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.

In 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.

A: I can’t 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.

Using 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.

But 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 this issue.

In addition, make sure airflow through the A/C condenser and radiator is clear and unobstructed. If the cooling system hasn’t been serviced recently a power flush may lower coolant and underhood temperatures measurably.

And 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. I’d 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.

Q: 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 can’t 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.

A: Acura’s 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 — operation at ambient temperatures under minus-20 degrees or above 110 — replacement is recommended every 60,000 miles.

With 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 pump.

  • get related content delivered to your inbox

  • manage my email subscriptions

ADVERTISEMENT

San Francisco - WP: M. Bumgarner 7 FINAL
Kansas City - LP: J. Shields 1
San Diego 10/23/14 7:25 PM
Denver
Detroit 10/26/14 8:30 AM
Atlanta
Buffalo 10/26/14 12:00 PM
NY Jets
St. Louis 10/26/14 12:00 PM
Kansas City
Houston 10/26/14 12:00 PM
Tennessee
Minnesota 10/26/14 12:00 PM
Tampa Bay
Seattle 10/26/14 12:00 PM
Carolina
Baltimore 10/26/14 12:00 PM
Cincinnati
Miami 10/26/14 12:00 PM
Jacksonville
Chicago 10/26/14 12:00 PM
New England
Philadelphia 10/26/14 3:05 PM
Arizona
Oakland 10/26/14 3:25 PM
Cleveland
Indianapolis 10/26/14 3:25 PM
Pittsburgh
Green Bay 10/26/14 7:30 PM
New Orleans
Washington 10/27/14 7:30 PM
Dallas
Houston 85 FINAL
Miami 90
Indiana 89 FINAL
Minnesota 107
Utah 105 FINAL
Oklahoma City 91
Portland 93 FINAL
Denver 75
Phoenix 114 FINAL
LA Lakers 108
LA Clippers 85 4th Qtr 12:00
Golden State 97
San Jose 3 FINAL
Boston 5
NY Rangers 4 FINAL(OT)
New Jersey 3
Toronto 5 FINAL
NY Islanders 2
Detroit 1 FINAL(OT)
Montreal 2
Arizona 3 FINAL(SO)
Nashville 4
Carolina 1 FINAL
Winnipeg 3
Philadelphia 0 FINAL
Chicago 4
Vancouver 3 FINAL
Dallas 6
Florida 4 FINAL(OT)
Colorado 3
Tampa Bay 2 FINAL(OT)
Calgary 1
Arkansas State 40 FINAL
Louisiana 55
Connecticut 10/23/14 6:00 PM
(18) East Carolina
Miami-Florida 10/23/14 7:00 PM
Virginia Tech
So Florida 10/24/14 6:00 PM
Cincinnati
Troy 10/24/14 6:30 PM
South Alabama
BYU 10/24/14 8:00 PM
Boise State
(6) Oregon 10/24/14 9:00 PM
California
North Texas 10/25/14 11:00 AM
Rice
UAB 10/25/14 11:00 AM
Arkansas
Rutgers 10/25/14 11:00 AM
(16) Nebraska
Maryland 10/25/14 11:00 AM
Wisconsin
Texas 10/25/14 11:00 AM
(11) Kansas State
Minnesota 10/25/14 11:00 AM
Illinois
Memphis 10/25/14 11:00 AM
SMU
North Carolina 10/25/14 11:30 AM
Virginia
San Jose St 10/25/14 12:00 PM
Navy
Northern Ill 10/25/14 12:00 PM
Eastern Mich
(25) UCLA 10/25/14 1:00 PM
Colorado
Akron 10/25/14 1:00 PM
Ball State
Massachusetts 10/25/14 1:00 PM
Toledo
Ohio U 10/25/14 1:00 PM
Western Mich
Ga Southern 10/25/14 1:00 PM
Georgia State
Kent State 10/25/14 1:30 PM
Miami-Ohio
Oregon State 10/25/14 2:30 PM
Stanford
Fla Atlantic 10/25/14 2:30 PM
(23) Marshall
Louisiana Tech 10/25/14 2:30 PM
Southern Miss
(1) Miss State 10/25/14 2:30 PM
Kentucky
Georgia Tech 10/25/14 2:30 PM
Pittsburgh
(22) West Virginia 10/25/14 2:30 PM
Oklahoma State
Texas Tech 10/25/14 2:30 PM
(10) TCU
Michigan 10/25/14 2:30 PM
(8) Michigan State
Boston College 10/25/14 2:30 PM
Wake Forest
Central Mich 10/25/14 2:30 PM
Buffalo
Vanderbilt 10/25/14 3:00 PM
Missouri
Old Dominion 10/25/14 3:00 PM
Western Ky
UNLV 10/25/14 3:00 PM
Utah State
Temple 10/25/14 4:00 PM
UCF
(15) Arizona 10/25/14 5:00 PM
Washington St
Texas-El Paso 10/25/14 6:00 PM
TX-San Antonio
Wyoming 10/25/14 6:00 PM
Colorado State
Syracuse 10/25/14 6:00 PM
(21) Clemson
Texas State 10/25/14 6:00 PM
ULM
(3) Ole Miss 10/25/14 6:15 PM
(24) LSU
(4) Alabama 10/25/14 6:30 PM
Tennessee
So Carolina 10/25/14 6:30 PM
(5) Auburn
(13) Ohio State 10/25/14 7:00 PM
Penn State
(20) USC 10/25/14 9:00 PM
(19) Utah
(14) Arizona State 10/25/14 9:45 PM
Washington
Nevada 10/25/14 10:59 PM
Hawaii
Montreal 10/24/14 5:30 PM
Ottawa
Saskatchewan 10/24/14 8:30 PM
Calgary
Hamilton 10/25/14 3:00 PM
Toronto
Brt Columbia 10/25/14 6:00 PM
Winnipeg
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

 
Close