Quote:
Originally Posted by glatt
-I pulled out the back seat and checked the voltage at the connector to the gas pump when the key was turned to "on." It had battery voltage at one conductor and 5 volts at another. The manual didn't say what it should have.
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Voltage to the pump typically should be 12 volts. No reason to put an expensive 12 volt to 5 volt regulator on pump power. So why is it only 5 volts?
I saw this once on another car. One transistor would not properly conduct in rare cases when it got warm. So the car would not start until that transistor cooled. Then works fine. Later I heard of a service bulletin for this problem.
That is but one example. Many reasons could explain this. But only 5 volts on what should be 12 volts is enough to concentrate on that symptom. To go further or say more requires electrical diagrams. Generally $40 from the only company that sells these books (Amazon apparently is not permitted to compete.)
All cars start same. When a switch is first placed on, then the fuel pump operates for a few seconds. You must be in a quiet area to hear it. In your case, it probably works most of the time but maybe does not work when something is too warm or has some other environmental change after long operation.
Moving on to other symptoms. For your problem to create a check engine light, you may have to aggravate the problem on multiple and consecutive restarts. For example, after each restart and when the engine is hot, floor it. Find some place (ie steep hill) to do this so that the engine demands full fuel. You may not feel a problem. But the check engine computer does. If you restart the engine only once without doing this, then you must repeat this test all over again.
A check engine light for this particular fault only lights when the same problem has been seen at least two or more times consecutively (after each restart). This problem would only be seen by a check engine light when the pump is taxed (full flow). If you restart the engine once and do not tax that pump, then the check engine light zeros its counter.