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Old 03-13-2007, 04:31 PM   #4
old_master
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Re: Timing mark moving.

A fuel pressure tester will turn out to be an invaluable tool. Pretty much have to have it if you're doing your own driveability repairs. The service engine light being off is not too surprising. Low fuel pressure will cause many driveability issues and still not turn the SES light on. Check fuel pressure first before jumping to any conclusions.

The fuel pump circuits are designed to energize the fuel pump continuously any time the key is in the START position. When the key is in the RUN position the fuel pump will operate provided the engine is running. If the engine stalls, or is not running for any reason, the ECM will shut off the fuel pump after approximately 2 to 3 seconds.

Fuel pressure test:
Install fuel pressure gauge to the test port near the distributor. Turn the key to the RUN position, (do not start the engine). While the fuel pump is running, fuel pressure must be 60-66psi. After approximately 2 to 3 seconds, the fuel pump will shut off. Fuel pressure must remain between 55-60psi for several minutes. A drop in pressure below 55psi indicates a leak. Most likely the fuel pressure regulator or the lines under the upper intake manifold are leaking.

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