Q. I am having a problem with my 1990 Buick Park Avenue that no one can correct. During summer and rainy weather it will sometimes not start. It takes several minutes to get it to turn over. Once it starts I can stop and start it throughout the day with no problems.

I have had this problem now for the past two years. During this time we have replaced many parts with no improvement.

Our repairman put the car on the computer and ran a diagnostic for us. All the readings were on target.

He is just as puzzled. And, of course, once I get it started and bring it to the gas station, he can turn it on and off all day and it will turn right over. Do you have any thoughts on what this might be?

A. Watert,

New Haven, Conn.

A. A good way to get to the bottom of a frustrating problem like this is to team up with your repair shop by acquiring some test data during an “uncooperative event.” We want to see if the Buick loses ignition, fuel pressure and/or fuel-injector drive commands.

Let’s start by checking for “spark,” using an ignition system tester (a $10 tool resembling a spark plug with a very wide gap).

To do so, (with the engine off) gently remove one of the spark plug wires from a spark plug and connect it to the tester. Connect the tester’s alligator clip to a metal engine part, step back from the engine area, and ask a helper to crank the engine. If a healthy blue spark snaps across the tool’s electrodes, you’ve got enough spark for two cars. If not, we’ve acquired our first piece of test data.

The next test is to verify “injector drive” by listening for clicking from the fuel injectors while the engine is cranking. (Be sure to tie back long hair and/or loose clothing when working near a cranking/running engine and touch only the components mentioned.)

The injectors might be difficult to hear, so use a closed umbrella as a stethoscope (the tip resting against a fuel injector, your ear held to the plastic handle). Your fuel injectors are concealed beneath a plastic trim panel atop the engine so seek assistance from a knowledgeable friend as necessary to find them. Clicking is good, quiet is not.

Our final check is fuel pump operation. Listen for a humming noise at the fuel tank filler (cap removed) while a helper cycles the ignition switch off, then on (run position), then off, in a five-second sequence. Humming is good, quiet isn’t.

The information you’ve acquired will not pin down the exact cause of the fault, but is a great start. My first hunch is a weak/failing fuel pump, although a couple of dozen other possibilities do exist.
Brad Bergholdt teaches automotive technology at Evergreen Valley College in San Jose, Calif.



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AP-NY-04-09-04 0618EDT