I've been dealing with the issue of my fuel guage dropping to empty for a couple years now. I've tried Techron numerous times, but it never worked for me. I'm finally loooking to replace the Fuel Sending Units (both driver and passenger side). The chespest price I got so far is $871 for both of them from GM .

Anybody know where I can possibly get them cheaper?

TIA

 

http://www.gmpartshouse.com/

http://www.gmpartsdirect.com/?gclid=...FQEeDQodTGp5Fg

Try here... It's about $100 for the left side and maybe $250 for the right...
That is, if they "ole brain" is working right...

 

If those were the prices of the fuel sending units I'd buy it today. Unfortunately, the $871 price was in fact from gmpapartshouse...

 

Give Seafoam a try,we use it in the shop with great results.It is at least worth a try!

 

Someone posted a while back that there was a REPLACEMENT SENDING MODULE for both sides. Its is just the electric module and NOT the entire sending /pump assy.

If it were me, I would research that option if it truly exist.. I would also try some SEAFOAM as recommended by rebelheart

If all the above fails,, you can contact forum member Steve Doten and ask him for the procedure that he did to remove the sensors and physically clean the electrical resistive strip and adjust the contact arms!

If you CLEAR the DTCs how long does it take for the gage to go to empty and what fuel system DTCs are you getting?

Have you tried to clean your fuel system ground G-401 in the driver rear wheel well on the side of the frame? If you post the DTCs that are being displayed, the service manual provides very specific troubleshooting and repair guidance.

BC

 

I believe MidAmerica has them now Bill.

 

Hey Bill!

Thanks for the tips. I'll look into the "replacement sending module". I'll check the G-401 ground as well. It takes about ~1hr of driving or so for the guage to go to empty after the DTC has been cleared. I'll have to check the codes.

Mike, I'l check out MidAmerica's site for the "replacement sending module".

Thanks guys!

 

I just replaced my fuel pump the damn guage didn't work right for 2 days after but has been fine since....well up until last night and well....that's another thread and a bigger issue

 

It never ends... Hope you get it figured out. I'll be purchasing both sending units and have it done as a winter project. I've learned to accept, that each year something will have to get repaired on this car.

 

oh I figured it out...it ain't pretty

 

I have been dealing with the same thing for a couple of months now. When the gauge drops and I run the codes the only code that comes up is

P1431HC

 

Heres the complete P1431 trouble guideL


DTC P1431 Fuel Level Sensor 2 Performance




Circuit Description
The right fuel level sensor 2, mounted in the rear side of the right fuel tank, measures fuel level changes within the right fuel tank. The Fuel Level sensor 2 has a signal and a ground circuit.

When the fuel level is high the sensor signal voltage is high. When the fuel level is low the sensor signal voltage is low.

The PCM uses inputs from the fuel level sensor 1 and the fuel level sensor 2 in order to calculate the total fuel remaining in both fuel tanks. The system sends this information via the serial data to the IPC. This information displays on the fuel gauge.

This diagnostic tests for a stuck fuel level sensor 2 signal. If the PCM determines that the fuel level (right tank) signal appears to be stuck based on a lack of signal variation expected during normal operation, this DTC sets.

The following is a description on how the fuel pump/system functions: An electric high pressure fuel pump attaches to the fuel sender assembly inside the left fuel tank. The in-tank fuel pump supplies fuel through an in pipe fuel filter/pressure regulator assembly to the fuel rail. The fuel pressure supplied by the fuel pump exceeds the fuel injectors required pressure. The fuel pressure regulator, which is part of the fuel filter assembly, regulates the fuel pressure supplied to the fuel injectors. Excess fuel returns from the fuel filter/regulator, through a separate fuel return pipe, to the left fuel tank. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The PCM controls the electric fuel pump operation through a fuel pump relay.

The left tank fuel pump also supplies a small amount of pressurized fuel to the right fuel tank siphon jet pump through the auxiliary fuel feed rear pipe. The pressurized fuel creates a venturi action inside the siphon jet pump. The venturi action causes the fuel to be drawn out of the right fuel tank. Fuel is then transferred from the right fuel tank to the left fuel tank through the auxiliary fuel return rear pipe. The fuel system is designed to maintain a greater level in the left fuel tank then the right fuel tank when the electric fuel pump is operating. The fuel transfer rate from the left fuel tank to the right fuel tank is less than the transfer rate from the right fuel tank to the left fuel tank. Therefore, with the electric fuel pump operating, the left fuel tank level should be higher than the right fuel tank level.

The fuel level in the fuel tanks equalize when the following occur:

The electric fuel pump is not operating.
The fuel level is greater than 50 percent.
Conditions for Running the DTC
The engine is operating.

Conditions for Setting the DTC
The secondary fuel tank is not empty.
More than 241 km (150 miles) have been accumulated.
The PCM does not detect that the fuel level in the right fuel tank moved by at least 3.0 liters (0.80 gallons).
OR

The secondary fuel tank is not empty.
The primary fuel tank is not full.
Engine operating greater than 60 minutes.
The primary tank does not achieve the top of its range. Observe, after operating the engine for greater than 60 minutes the fuel in the right fuel tank will transfer to the left fuel tank.
OR

The secondary fuel tank is empty.
The primary fuel tank is full.
The fuel level in both fuel tanks does not change after traveling more than 284 km (200 miles). Observe, if the secondary fuel tank is empty, the primary fuel level should decrease after 284 km (200 miles).
Action Taken When the DTC Sets
The PCM stores the DTC information into memory when the diagnostic runs and fails.
The malfunction indicator lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
The vehicle fuel gauge displays empty.
The Check Gauge lamp illuminates.
The Driver Information Center displays a message.
Conditions for Clearing the DTC
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
Use a scan tool in order to clear the DTC.
Diagnostic Aids

Important
Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616-A . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

Depending on the current fuel level, it may be difficult to locate a malfunctioning sending unit. The malfunction may only occur when the fuel level is full or near empty. The fuel sending unit may need to be removed for further diagnosis. A fuel level sensor that has an intermittent condition causes this DTC to set. Remove the fuel level sensor. Refer to Fuel Sender Assembly Replacement in order to test the resistance of the sensor. The resistance of the sensor should change from 40 to 250 ohms. Replace the sensor if the resistance did not change or was out of range.


Important
When inspecting for a deformed or warped fuel tank, measure the resistance of the suspect fuel level sensor at empty, with the sensor in the fuel tank, and again with the sensor removed from the fuel tank. The measured resistance values should be same empty. If the measured resistance values are not the same, refer to Fuel Tank Replacement in Engine Controls.


The following occurs with this DTC set:

The vehicle fuel gauge displays empty.
The Check Gauge lamp illuminates.
The driver information center (DIC) displays a message.
The voltages in the Fuel Level Conversion Table are approximate values. Use this table to aid in diagnosis.
Fuel Level Conversion Table

Approximate Values

Fuel Level
Left Tank voltage
Right Tank Voltage

100%
2.5V
2.5

75%
2.5V
1.5V

50%
2.5V
Less than 1V

25%
1.7V
Less than 1V

0%
Less than 1V
Less than 1V


If the fuel level sensor is operating OK, test the operation of the Jet Pump.
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.

Use DTC P0461 table if DTCs P0461 and P1431 set.

This step determines if a circuit condition is causing the fuel level signal to be at a fixed value.

This step determines if a circuit condition is causing the fuel level signal to be at a fixed value.

This step determines if fuel is being delivered to the right fuel tank jet pump.

The fuel pump will run for 2 seconds each time it is commanded ON with the scan tool. The fuel pump must be enabled several times to achieve the time specified in the diagnostic table.

This step verifies that the left fuel level sender voltage is not above the specified value. If the left fuel level sender voltage is above the specified value, the left fuel tank will have to be drained.

Drain the left fuel tank until the left fuel sender voltage is within the specified range in order to keep fuel from leaking from the left fuel tank.

This step determines if fuel is being transferred to the left fuel tank.

The fuel pump runs for 2 seconds each time it is commanded ON with the scan tool. The fuel pump must be enabled several times to achieve the time specified in the diagnostic table.

Foreign material in the fuel tank may cause the sensor to stick. Inspect the strainer for interfering with the float arm. A stuck sensor may not be apparent when the sensor is removed from the fuel tank. The following may have caused the DTCs to set:

The fuel tanks over filled.
Fuel level that is almost empty and then re-fueled with only a couple gallons.
The Fuel Level sender un-stuck while re-fueling.
The Fuel Level sender un-stuck on rough road or going around a corner.
The PCM will not reset the mileage for this diagnostic if the fuel tanks are re-fueled to the same level as before the repair was made. Perform the following procedure in order to re-fuel the vehicle after replacing a sending unit or fuel tank.

Add 25 percent of the fuel that you removed before the repair.
Start and idle the engine for 5 minutes.
Turn OFF the engine.
Add the remainder of the fuel.
Step
Action
Values
Yes
No

1
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
Is DTC P0461 also set?
--
Go to DTC P0461 Fuel Level Sensor Performance
Go to Step 3

3
Disconnect the right fuel level sensor electrical connector.
Jumper the fuel level signal circuit to battery ground.
Monitor the right fuel level sensor voltage parameter with a scan tool.
Is the right fuel level sensor voltage at the specified value?
0.0V
Go to Step 4
Go to Step 11

4
Jumper the fuel level signal circuit and ground circuit together.
Monitor the right fuel level sensor voltage parameter with a scan tool.
Is the right fuel level sensor voltage at the specified value?
0.0V
Go to Step 5
Go to Step 12

5

Caution
Gasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.


Monitor the fuel level in the left tank with a scan tool.

Important
If the left fuel tank is empty DO NOT add more than 15 liters (4 gallons) of fuel.


Add fuel if the left fuel tank is empty.
Disconnect the auxiliary fuel feed rear pipe from the right fuel tank. Refer to Y car fuel system .
Insert the auxiliary fuel feed rear pipe into an approved gasoline container.
Command the fuel pump ON for the specified time with a scan tool.
Measure the volume of fuel.
Is the volume of fuel greater than the specified value?
10 seconds

300 ml (0.633 pt)
Go to Step 6
Go to Step 13

6
Observe the left fuel level sender voltage with a scan tool.

Is the left fuel level sender voltage above the specified value?
1.25V
Go to Step 7
Go to Step 8

7
Drain the left fuel tank until the left fuel sender voltage is within the specified range. Refer to Fuel Tank Draining Procedure .

Did you complete the action?
1.0-1.25V
Go to Step 8
--

8

Important
Inspect the auxiliary fuel feed rear pipe if the right fuel tank is empty. Fuel flow to the right fuel tank is decreased during fueling if the crossover hose is collapsed or restricted.


Connect the auxiliary fuel feed rear pipe to the right fuel tank.
Disconnect the auxiliary fuel return rear pipe from the left fuel tank. Refer to Y car fuel system .
Insert the auxiliary fuel return rear pipe into an approved gasoline container.
Command the fuel pump ON for the specified time with the scan tool.
Measure the volume of fuel.
Is the volume of fuel greater than the specified value?
8 seconds

332.6 ml (0.703 pt)
Go to Step 9
Go to Step 14

9
Remove the right tank fuel level sensor. Refer to Fuel Sender Assembly Replacement .
Inspect for the following:
A stuck Fuel Level sensor (i.e. the fuel strainer interfering with the sender float arm)
Fuel tank deformed
Foreign material in the fuel tank (ice)
Did you find and correct the condition?
--
Go to Step 18
Go to Step 10

10
Connect the DMM between the fuel level sensor signal circuit and the fuel level sensor ground circuit (sensor side).
Set the DMM to the 400ohms range.
Sweep the fuel level sensor from stop to stop.
Does the resistance vary between the specified values?
40ohms (±1ohms) to 250ohms (±2.4ohms)
Go to Diagnostic Aids
Go to Step 15

11
Disconnect the PCM connector C2 located on the opposite side of the manufacturer's logo. Refer to Powertrain Control Module (PCM) Replacement .
Test the right tank fuel level signal circuit for high resistance.
If you find a condition, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 18
Go to Step 16

12
Disconnect the PCM connector C1 located on the same side as the manufacturer's logo. Refer to Powertrain Control Module (PCM) Replacement .
Test the right tank fuel level ground circuit for an open or for high resistance.
If you find a condition, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 18
Go to Step 16

13
Inspect the auxiliary fuel feed rear pipe for restrictions and repair as necessary.

Is the action complete?
--
Go to Step 18
--

14
Inspect the auxiliary fuel return rear pipe for restrictions and repair as necessary.

Did you find and correct the condition?
--
Go to Step 18
Go to Step 15

15
Replace the right tank fuel level sensor. Refer to Fuel Sender Assembly Replacement .

Is the action complete?
--
Go to Step 18
--

16
Inspect for a poor connection at the PCM. Refer to Testing for Intermittent and Poor Connections in Wiring Systems.
If you find a poor connection, repair as necessary. Refer to Repairing Connector Terminals in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 18
Go to Step 17

17

Important
Program the replacement PCM.


Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .

Is the action complete?
--
Go to Step 18
--

18
Select the Diagnostic Trouble Code (DTC) option and the Clear Information option with the scan tool.
Start the engine and idle at the normal operating temperature.
Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number with the scan tool.
Operate vehicle within the Conditions for Running this DTC as specified in the supporting text, if applicable.
Does the scan tool indicate that this test ran and passed?
--
Go to Step 19
Go to Step 2

19
Select the Capture Info option and the Review Info option with the scan tool.

Are any DTCs displayed that have not been diagnosed?
--
Go to Applicable DTC Table
System OK



--------------------------------------------------------------------------------
Document ID# 610929
2000 Chevrolet/Geo Corvette



Symptoms
Important Preliminary Checks Before Starting
Perform the Powertrain On Board Diagnostic (OBD) System Check before using the Symptom Tables, and verify that all of the following conditions are true:

The PCM and the malfunction indicator lamp (MIL) are operating correctly.
There are no DTCs stored.
The engine coolant temperature is not above 130°C (266°F). This condition causes the PCM to operate in Engine Coolant Over Temperature/Fuel Disabled Mode. While in Engine Coolant Over Temperature/Fuel Disabled Mode, the PCM turns the fuel off to 4 cylinders at a time in order to keep the engine temperatures from reaching damaging levels. The system perceives Engine Coolant Over Temperature as a lack of power, a miss, or a rough idle. If the vehicle is operating in Engine Coolant Over Temperature/Fuel Disabled Mode, refer to Engine Overheating in Engine Cooling for diagnosis.
The scan tool data is within the normal operating range. Refer to Scan Tool Data List .
Verify the customer concern and locate the correct symptom in the table of contents. Inspect the items indicated under that symptom.
Several of the symptom procedures ask for a Careful Visual/Physical Check. This step is extremely important, and can lead to correcting a problem without further checks and can save valuable time.
If the intermittent condition exists as a start and then a stall, inspect for any DTCs relating to the theft deterrent system. Verify the proper installation of electrical options such as lights, cellular phones, etc.
Use the following tables when diagnosing a symptom concern:
Hard Start
Surges/Chuggles
Lack of Power, Sluggishness, or Sponginess
Detonation/Spark Knock
Hesitation, Sag, Stumble
Cuts Out, Misses
Poor Fuel Economy
Rough, Unstable, or Incorrect Idle and Stalling
Dieseling, Run-On
Backfire
If the condition cannot be isolated using the appropriate table, refer to Intermittent Conditions for further diagnosis.

--------------------------------------------------------------------------------
Document ID# 554856
2000 Chevrolet/Geo Corvette

 

WOW! Thats a lot of info! Thanks! So does that mean I have to get a scan tool in order to more accurately diagnose the problem, or would you just replace the right side fuel sending unit and see if that fixes it?

Thanks Bill

 

YOU,,,, have a SCAN TOOL built right into your IPC. If you mean purchase a TECH 2,, You really do not need one. For the most part, you can use a meter and measure the specific readings..

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

 

Left sender: AC Delco SK1318 = $97.79
Tank gasket w/screws: AC Delco G4 = $65.79

Right tank pump module complete: Carter P74899M = $398.79 (incls gasket and screws) = $398.79

RockAuto.com


Total = $562.37 - 5% Discount (I have the discount code I can give you) = $534.25 + shipping.

HTH

Edit: Found the left sender (AC Delco SK1318) at shopacdelco.com for $80.25 so you save another $17.00