To check the fuel pump, search for a small Schrader valve (a valve that looks similar to a wheel air-fill valve) on the fuel rail. Take a blunt object that fits inside the hole of the valve and depress the plunger just as if you were letting air out of a tire. Have an assistant turn the ignition on. The circuitry for the fuel pump is designed to have the pump run for about 1 - 2 seconds after turning on the ignition key. If fuel starts spraying out of the valve, you know the pump is good.
If there is no fuel spray, you need to check the electrical by locating the fuel pump relay. The relay should have a schematic of terminal numbers and what they do. Two are for the relay coil, two are for the high-current (powers the fuel pump). One terminal for the high-current side is always hot when the ignition key is turned on. One terminal for the coil side (of the relay) is "hot" for about 2 seconds after the key is turned to "on" position.
The ignition coil is easier to check. Disconnect a plug wire, insert a screwdriver so that it makes good contact with the metal terminal inside the boot, bring the screwdriver close to any metal ground, and crank the engine. If a spark jumps from the screwdriver to ground, that part of the coil is good. The coil is a coil pack. Check all 3 plug cables nearest the radiator. If they all check OK, you don't need to worry about the plugs near the firewall because there's only 3 coils for 6 cylinders. The front and back plugs share the same coil(s), so if the front spark, the rear three will spark also.
I'd hold off on doing much to the computer. They rarely fail. It's most often a failed sensor or shorted acuator which pulls systems down and makes things not want to work.
By the way, while you're depressing the plunger for the fuel Schrader valve, try to get a gasoline sample to check for water contamination or similar.
As for the ignition key assembly being possibly bad, look to see if (in the dash), the Check-Engine light illuminates while in the Key-On, Engine-Off mode. This simply verifies that power is reaching the PCM.
It's a bit more complicated than that, but at least you have a start to your diagnostics.
Friday, August 28th, 2009 AT 3:44 PM