the car was ran with race gas 2004 coupe and codes p0171,p0174,p2066 showed up

 

P0171 Fuel Trim System Lean Bank 1
P0174 Fuel Trim System Lean Bank 2

Couldn't find the last code you mentioned.

 

what is it happening

 

When you say "race gas" .... what do you mean ... 100 octame UNLEADED or something like 116 octane LEADED fuel ???

 

107 low LEADED

 

You have probably damaged your catalytic converters and/or your Heated O2 sensors.

NEVER EVER EVER put leaded fuel OF ANY KIND in a C5 Corvette equipped for the street. It does bad things to the engine and the exhaust system.

If you want to run race fuel, most tracks have 100 octane UNLEADED fuel available, or if your local track doesn't have it, go to either of these locations to find it .......

http://www.sunocoinc.com/site/Consum...T100Locations/

http://www.rockettbrand.com/dealers/dealers.htm

Unless your PCM has been specially "tuned" for high octane fuel, running anything over 93 octane won't increase the cars performance. About the only advantage to fuel higher than 93 octane is knock protection when really hammering the engine for extended periods of time.

The diagnostic for the P0171 and P0174 are the same ....

1) Check for any other DTCs first (EDIT - the P2066 would have no impact - so skip to next item if these are your only DTCs set). The Manual recommends fixing other engine related DTCs first as they may be the cause of the lean condition.

2) Using a scanner, observe the Long Term Fuel Trim (LTFT) setting. If it is above 23 percent (which it has to be to have set the DTC) go to step 3

3) Check the output of the Heated O2 sensors. With the engine running they should display a voltage between 200-800 mv and he value should be fluctuating. (I'm betting this is where the problem is). Replace the O2 sensors if they fail this test. Also check the wiring near the sensors for any broken/damaged wires. If they are OK ...

4) Check for contaminated fuel (We know the answer to this one ... if you have any remaining leaded fuel in the tanks you should consider draining it, rather than running it through the engine and possibly doing further damage).

5) Check for leaks in the areea of the exhaust manifold

6) Check for vacumn leaks at the intake manifold, throttle body, and injector O-rings

7) Check the air induction system for leaks

8) Check the AIR system for leaks, improper air delivery, or the shut-off valves not closing

9) Check the crankcase ventilation system for leaks

Somewhere in these steps you should have found the problem. Be sure to disconnect the battery after finding the problem to reset your LTFT, and clear the codes using the RESET key when they are displayed on the DIC.

Everything should be fine after that ....

 

Here is your P2066 code info:

DTC P2066
Circuit Description
The right/secondary fuel level sensor measures fuel level changes within the right/secondary fuel tank.

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 powertrain control module (PCM) uses inputs from the left/primary fuel level sensor and the right/secondary fuel level sensors in order to calculate the total fuel remaining in both fuel tanks. The PCM sends this information via class 2 to the IPC.

This diagnostic tests for a stuck right/secondary fuel level sensor 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.

Conditions for Running the DTC
The engine is operating.

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

The right/secondary fuel tank is not empty.
The left/primary fuel tank is not full.
Engine operating greater than 40 minutes.
The left/primary fuel tank does not achieve the top of its range. Observe, after operating the engine for greater than 40 minutes the fuel in the right/secondary fuel tank will transfer to the left/primary fuel tank.
OR

The right/secondary fuel tank is empty.
The left/primary fuel tank is full.
The fuel level in both fuel tanks does not change after traveling more than 284 km (200 mi). Observe, if the right/secondary fuel tank is empty, the left/primary fuel level should decrease after 284 km (200 mi).
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 gage displays empty.
The check gages indicator illuminates.
The driver information center displays the LOW FUEL message.
Conditions for Clearing the MIL or DTC
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.
A last test failed, ore current DTC, will clear when the diagnostic runs and does not fail.
Use a scan tool in order to clear the MIL or DTC.
Diagnostic Aids

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 the same at empty. If the measured values are not the same, refer to Fuel Tank Replacement in Engine Controls.

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 Engine Controls 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.

Step
Action
Values
Yes
No

Schematic Reference: Instrument Cluster Schematics

1
Did you perform the IPC Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - Instrument Cluster

2
Connect a scan tool, record the left/primary and right/secondary fuel level sensor voltages in the powertrain control module (PCM) data list.
Remove 5 gallons of fuel. Refer to Fuel Tank Draining Procedure in Engine Controls.
Record the voltage on the left/primary and right/secondary fuel level sensors.
Start the engine, let the engine idle for 20 minutes.
Did the voltage increase on the left/primary fuel level sensor and decrease on the right/secondary fuel level sensor after 20 minutes?
--
Go to Step 4
Go to Step 3

3
Remove the right/secondary fuel tank. Refer to Fuel Tank Replacement in Engine Controls - 5.7L.

Is there any fuel in the right/secondary fuel tank?
--
Go to Fuel System Diagnosis in Engine Controls - 5.7L
Go to Step 4

4
Remove the right/secondary fuel level sensor. Refer to Fuel Level Sensor Replacement - Right in Engine Controls - 5.7L.
Inspect for the following items:
The fuel level sensor is stuck, perhaps due to an interface with the fuel strainer.
The fuel tank contains foreign material, for instance, ice.
Warped fuel tank.
Did you find and correct the condition?
--
Go to Step 7
Go to Step 5 --

5
With the DMM, measure the resistance of the fuel level sensor while moving the float arm.
Observe both the analog and digital displays on the DMM.
Does the resistance change smoothly across the specified range?
40-250ohms
Go to Diagnostic Aids
Go to Step 6

6
Replace the right/secondary fuel sensor. Refer to Fuel Level Sensor Replacement - Right in Engine Control - 5.7L.

Did you complete the replacement?
--
Go to Step 7
--

7
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the conditions for running the DTC.
Does the DTC reset?
--
Go to Step 2
System OK

Bill