Fuel gauge with full tank reading empty/ flashing low fuel light. Engine dyes two miles later. (2 Viewers)

[obe12]

Some news to report, the replacemen Sequoia ECU replacement in place of my 99 ECU can be flashed either way, Relay or Fuel Pump ECU.

I run a teat today on my Fuel Pump with my DC power supply, at 7.8 volts 6 amps, 10 volts 8 amps, and 13.5 Volts 10 Amps. My AEM E85 capable FP is rated at 43 psi and 13.5 Volts.. Its voltage ran ge is 6-18 volts. I am going to reach out to AEM and ask can I supply low, medium and Hi Voltages and not compromise Pump life. My 387600 mile OEM pump lasted years operating this way. My plans is E85 and Supercharger 7-8 PSI boost, with 365 CC injectors, Air Fuel ratio wide band gauge, with Hi Flow E85 capable fuel pump with Adjustable Fuel pressure regulator. Supercharger Elate supplied is on its way and due hopefully before the New Year.

If AEM fuel pump allows Low, Med, Hi operation, I have to make sure no fuel lean out conditions will happen under boosting 7-8 PSI at Sea Level. The new injectors 365 CC should help keep the required fuel pressure down.

I will update once I know more.

Tex

Just some update:

I called AEM, aka Holley parent a US company.

We spoke about my OEM hi / Medium / Low via Fuel Pump ECU. The AEM pump at 8 volt is 6 amp, 10 volt is 8 amp, 13.5 is 10 amp Low Med High…

Confirmed AEM 6-18 volt operation voltage range, and their pump will operate fine and not cause premature failure doing so.

Now the question is: boosting will the truck run lean at boost or transitioning to Medium to High Fuel Pressure under load.

Time will tell once I upgrade the engine with the Supercharger. Once I upgrade it, new higher flow injectors 365 cc, fuel pressure adjustable regulator and new colder spark plugs.

I start trial runs, on if mixture is ok. Then determine if lean out spots under engine load fuel demands.

If pump can’t keep up, then require the Fuel Pump ECU modification to command hi speed only,
That’s another story in itself.

Tex

 

[obe12]

Just some update:

I called AEM, aka Holley parent a US company.

We spoke about my OEM hi / Medium / Low via Fuel Pump ECU. The AEM pump at 8 volt is 6 amp, 10 volt is 8 amp, 13.5 is 10 amp Low Med High…

Confirmed AEM 6-18 volt operation voltage range, and their pump will operate fine and not cause premature failure doing so.

Now the question is: boosting will the truck run lean at boost or transitioning to Medium to High Fuel Pressure under load.

Time will tell once I upgrade the engine with the Supercharger. Once I upgrade it, new higher flow injectors 365 cc, fuel pressure adjustable regulator and new colder spark plugs.

I start trial runs, on if mixture is ok. Then determine if lean out spots under engine load fuel demands.

If pump can’t keep up, then require the Fuel Pump ECU modification to command hi speed only,
That’s another story in itself.

Tex

Report the fix to my intermittent Flashing low level light / and 2 miles later engine stalls out.

Previous, with truck running no fuel light flashing tank reading full, I pulled in both sides of this connector, and truck died.

Opening the connector I find blue corrosion in the socket terminals on the negative ground pin.

I de pin the connector, and de pin one wire only at a time on the sender wires. Each wire I took loose to short open, two of these sender wires cause low fuel ON light and low fuel indication. The 3rd wire of the sender I de pinned recreated my intermittent flashing low fuel light with low fuel on the gauge.

This open wire was the:

Yellow green… recreated the flashing light.

The plan cut out this connector and crimp new terminals on the wires, and re pin the connector. Now 20 gauge wires are the small wires and 14-16 on the large wires. The replacement connector accommodated the larger wire with larger connectors for better connection. The smaller wires smaller connector pins.

I found a zip tie to anchor the new connector to the body to support the harness.

Problem solved

Tex

 

[2001LC]

Report the fix to my intermittent Flashing low level light / and 2 miles later engine stalls out.

Previous, with truck running no fuel light flashing tank reading full, I pulled in both sides of this connector, and truck died.

Opening the connector I find blue corrosion in the socket terminals on the negative ground pin.

I de pin the connector, and de pin one wire only at a time on the sender wires. Each wire I took loose to short open, two of these sender wires cause low fuel ON light and low fuel indication. The 3rd wire of the sender I de pinned recreated my intermittent flashing low fuel light with low fuel on the gauge.

This open wire was the:
View attachment 3518609
Yellow green… recreated the flashing light.

The plan cut out this connector and crimp new terminals on the wires, and re pin the connector. Now 20 gauge wires are the small wires and 14-16 on the large wires. The replacement connector accommodated the larger wire with larger connectors for better connection. The smaller wires smaller connector pins.

I found a zip tie to anchor the new connector to the body to support the harness.

Problem solved

Tex

View attachment 3518613

View attachment 3518614

View attachment 3518615

Good job.

Tips:
Most OEM wire housing blocks, are still available. Which these come with new seal.
Packing new or old wire housing blocks, with dielectric grease. Helps keep moisture out.

 

[obe12]

Almost sounds like a worn wire, intermittent short or something, but that would likely trip a fuse right? Try shoving some dielectric grease in the connector?

EDIT: Just trying to think what’s going to hit the sender and the pump simultaneously. An intermittently bad sender would just affect the gauge I would think

The open on only the yellow green creates the flashing level light.

This all got created by unpluging this connector to un pressurize the fuel lines per the manual, to change the e85 hi flow pump in my tank.

This plug being disturb started this intermittent issue that he day after heavy rain that morning.

The blue corrosion shows evidence of bad connection to the pump motor. Pulling on the wires actually cause the truck to quit.

Not the only shared parts is the hanger for the pump / sender and the connector to the sender, connector to this harness.

Others have had similar issues at the connection point… before if you take the time to read the posts.

New connector to minimize the water intrusion to the connector, and have greasy clean pins. Yea dielectric grease was used inside the plug with pushed locked.

The gauge provides the ground, power to and sender complete the termination and returns a signal to the gauge.

One open wire creates the low light flashing. Assumption is intermittent connection at this old connector. Pulling on the wires now doesn’t recreate the issues.

Time tells all. Needed a connector, it got one.
If the sender is failing, we will know with time.
From the most common problem, most likely it was just the connector.

Tex

 

[obe12]

Follow up on the new replacement Connector, this connector has 2 larger pins and 3 same size pims like the old connector. I wasn’t happy seeing 20-22 gauge pins used on 14-16 gauge wires. The old connector all the pins where the same size pins on two different size wires. Why I got a connector with larger 2 pins for fuel pump wires . 14-16 gauge and 3 pins for the sender at 20-22 gauge.

This just makes sense larger pins for heavier gauge wires and new pump pulls 10 amps.

1/2 tank of gas used and working perfectly. No more gremlins so far. Aka zero fuel gauge, flashing low level light and stalling out.

I pulled and twisted the wires after the new connector was installed to check for breaks in the wiring from age ect. So far nothing is happening out of the ordinary.

I will take it… trust it to not leave me stranded.

Tex