Engine quits after 7 minutes

[WARP TEN]

Originally Posted by A26B

Sounds to me like a primary fuel pump has failed


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I'm with Jerry--that would be my thought. --Bob

[A26B]

Originally Posted by kieranod1

I thought so also and replaced both fuel pumps and filter but still the same result.

Have you tested rail pressure for each, individual pump at rail, since replacement?
Also verify primary pump fuse.


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[kieranod1]

Hi guys, back in town, checked the fuel pressure she is steady at 40 to 42 psi even after she shuts down. I put her up on the lift and the O2 sensors and wiring look good and intact. i also seem to have a vacuum leak because my secondary injector vacuum pump won't stop running.

[SAM/CH ZR-1]

Originally Posted by kieranod1

I thought so also and replaced both fuel pumps and filter but still the same result.

Keep us informed where the problem is. Did you ever remove the plenum?

[tpepmeie]

I?m with Jerry. If you replaced the pumps and no change, check the FP1 fuse.


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[LGAFF]

Did you verify the O2 sensors are working properly and not just a visual?

[max76]

Some years ago my car has got about the same problem...check the yellow connector on the frame of the fuel pump assembly...my wires wasn't in good conditions...like if they were burn

[mhobtr]

I had this same problem and it turned out to be the primary fuel pump. The pumps had been replaced before and I didn't like the looks of their work so I bought an entire new OEM assembly. Installed it and...SAME PROBLEM!

Making a long story short, it turned out that the check valve on the new secondary pump wasn't working so when the secondary pump cut off, the primary pump back flowed into the tank.

Actually turned out that neither check valve in the new pumps worked so I replaced both and haven't had a problem since.

You might try installing a harness adapter to swap the pumps from primary to secondary to see if it corrects the problem. But, if both check valves are bad, as in my case, the problem will persist.

[kieranod1]

Thanks guys, the fuel pump fuse was fine, I will check the connector on the frame of the fuel pump assembly.I will also look into the check valve issue after I dive into the service manual. Thanks

[Paul Workman]

Normally, BOTH pumps run when the engine is first started, but if the FULL POWER mode is not activated, the secondary pump cuts off after 5 or so minutes. A fuel pressure ~ 45 psi and then dropping to zero at the moment the engine fails suggests the primary fuel pump has failed. Check the fuse(s) first (if you haven't already).

Kinda late to the party, but an easy way to "wring out" the fuel pumps is measure the current @ the fuel pump diagnostic connector.

Each pump normally draws 4-5 amperes for a total of 8-10 Amps with the ignition switch in the OFF position.

Place a fuel pressure pump on the fuel rail (to verify pressure later)
Place your VOM (red) jumper in the Amps position (see pic) and IMPORTANT! turn the switch to "A" (Amps) BEFORE making further steps/measurements. (Otherwise, you may damage the meter at worst, or blow the internal fuse at the least!)
Connect the (properly configured) meter between the fuel pump diagnostic test point (the little wire with a connector attached, jutting out of the wire loom (about an inch) by the windshield wiper motor, and the POSITIVE terminal of the battery.
If the reading is 8-10 Amps, and you can hear the pumps running, you will know that both pumps are running, verified by the pressure gauge attached to the fuel rail. But, if the reading is 4 or 5 amps, then one of the pumps is not running. (At that point, since the engine ran for several (7?) minutes before quitting, we can assume the secondary pump is running normally and the primary pump has failed.)

IMPORTANT! Soon as you're finished measuring current, remove the meter from the circuit and reconfigure the jumpers to reading VOLTS and switch the meter OFF or to another test scale. FAILURE to do so is the primary reason for a blown fuse inside the meter!

The first pic shows moving the (red) lead to the "A" (ampere) position, and the meter dial selection on the 10 Amps position.

The second pic shows a normal reading of 8.74 amperes for BOTH pumps (8-10 amps is normal, varying depending on which pumps are installed).

The 3rd pic show the little red wire sticking out of the wire loom close to the wiper motor. (pardon the yellow jumper wire connecting the black lead of the meter to the test connector at the wire loom).