will not start suspect fuel problem?

1988 FORD F-150
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TWORK
  • MEMBER
  • 2 POSTS
My 88 Ford F150 W/300 6 cyl eng will not start. Suspect fuel problem but
when fuel line was disconected it had no pressure. cahnged main fuel pump and still would not start. checked old pump and it works.
checked the wires with volt meter and no power.checked resistance and got a pos reading on both wires. has duel tanks but switching them does no good
Jan 15, 2006 at 12:17 PM

What to check next

Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.

Have the reported loss of pump power and the dual-tank fuel-supply system diagnosed together before replacing more parts. Include the tank-switching valve suggested in the reply, without treating it as an established cause.

Guidance references and applicability

Source: Original question and visible replies. Owner reports and other participants' experiences are distinguished. Next steps are editorial guidance for obtaining diagnosis or clarifying the reported findings; they are not a verified repair procedure or an independently confirmed component diagnosis.

Read the replies · Discussion summary and reported outcome

AI-ASSISTED GUIDANCE · REVIEWED BY 2CARPROS
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STRAILER
  • ✓Experienced Mechanic
  • 55,561 POSTS
Hello,

these trucks had a problem with the switching valve not working and cutting all gas off. It is located between the two tanks at the frame rail.

Here is a guide as well to go over the basics if the valves checks out.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run some tests and get back to us so we can continue helping you.

Cheers, Ken

May 31, 2021 at 5:47 AM
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Suggested Repair

Inspect the dual-tank fuel switching valve located between the tanks at the frame rail, since a failed valve can shut off all fuel. If the valve checks out, continue basic no-start diagnostics.

Conversation Summary

The owner of a 1988 Ford F-150 with a 300 six-cylinder reported a no-start suspected to be fuel-related. Disconnecting the fuel line showed no pressure, and replacing the main fuel pump did not help; the old pump still worked. The wiring had no power, resistance was present on both wires, and switching between the dual tanks made no difference. The expert advised that these trucks commonly have a failed tank switching valve between the tanks at the frame rail that can cut off all fuel, and recommended checking that valve and reviewing basic no-start tests if it is good.

Discussion summary

will not start suspect fuel problem?

A 1988 Ford F-150 with a 300-cubic-inch six-cylinder engine and dual tanks would not start. The owner reported no fuel pressure and no power at the checked pump wires; replacing the main pump had not helped.

Reported outcome: No follow-up test results or successful repair were reported.

The reply proposed a switching-valve fault, but no test confirmed it. The owner's electrical findings and exact fuel-system configuration need verification.

Read the original discussion

AI-ASSISTED SUMMARY · REVIEWED BY 2CARPROS
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