I just had Dynatech Long Tube headers installed on my 98 C5, sounded good at idle, but runs very badly.

Do I need to have the CPU/PROM rebooted or reprogrammed ? I had it towed to the nearest Chevy dealer.

I would appreciate any help you can provide.

 

sometimes the front O2 sensors get crossed during the install. The sensor on the driver side before the cats should plug into the drivers side connection, passneger side on the passenger side. Also check plugs and plug wires. the wires are easy to break and you may not know it by looking.

Good luck.

 

check the plugs you may have cracked the porcelain

 

Check O2 sensor wires first and plugs. My bet is O2 wires crossed, easy fix.

 

Good advise above! a tune will help get the most out of the new headers, no matter the brand. Find a tuner, the dealer is a roll of the dice. I have the same headers and no probs like you describe. The dealer will NOT repro your car, Government Motors won't let them!

 

Why in the world did you have it towed to a Chevy dealer. You need to get w/ forum members in your immediate area and get a recommended shop that knows the in and outs of the C/5. Good luck.

 

A tune is not necessary for headers only. (depending on the headers..i.e. Melrose headers dont need a tune whereas LG's will)..unless your DIC is throwing emissions codes. I agree with all the other troubleshooting above though.

 

Headers alone usually will not effect the tune. If it does, it usually a slight drop in fuel milage or a flat spot in mid RPM area. Sounds like the people who installed the headers forgot to make all the proper connectons, cracked a spark plug:



Or a bad or improperly connected sparkplug wire,
.

The very first thing to do is read your DTCs. If you dont know how to read your own, check this out:

READING YOUR Engine Diagnostic Codes (DTCs)

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 etc…)
3) Press and hold OPTIONS
4) While holding OPTIONS, press FUEL four times within a 10-second period.

Initially, on-board diagnostics go into an Automatic Mode which 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. ( 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 kinds 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.
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.

Here is very good site of DTC definitions:


http://www.gearchatter.com


Make sure to include the H or C suffix!!

See if your Check Engine Light (CEL) is flashing when the engine runs bad. If it does, its telling you that the engine is misfiring, DTC P-0300. If it is flashing, check all your wires and plugs.



DTC B0016 RF Deployment Loop Resistance Low DTC B2723 PASS-Key Detection Circuit
DTC B0017 RF Deployment Loop Open DTC B2735 PASS-Key Programming Mode Active
DTC B0018 RF Deployment Loop Short to Ground/Voltage Out of Range DTC B2795 Suspension Control Select Switch Circuit Malf
DTC B0022 LF Deployment Loop Resistance Low DTC B2852 Telescop Column In Switch Shorted to Ground
DTC B0024 LF Deployment Loop Short to Ground/Voltage Out of Range DTC B2857 Telescop Column Out Switch Shorted to Ground
DTC B0026 LF Deployment Loop Open DTC B2860 Telescoping Column Position Sensor Failure
DTC B0051 Deployment Commanded DTC B3109 Keyless Entry Transmitter Low Battery
DTC B0053 Deployment Commanded with Loop Malfunctions Present DTC B3577 Suspension Control Select Switch Contact Malf
DTC B0090 Active Switch Voltage Out of Range DTC C0550 ECU Malfunction
DTC B0091 Active Switch: Wrong State DTC C0563 Calibration ROM Checksum Error
DTC B0432 Rear Defogger Relay Circuit DTC C0615, C0620, C0625 or C0630 Suspension Position Sensor Circuit
DTC B0433 Rear Defogger Relay Circuit DTC C0665 Chassis Pitch Signal Circuit
DTC B0502 RH DRL Relay Circuit DTC C0690 Damper Control Relay Circuit Malfunction
DTC B0503 RH DRL Relay Circuit DTC C0691 Damper Control Relay Circuit Range
DTC B0507 LH DRL Relay Circuit DTC C0693 Damper Control Relay Circuit High
DTC B0508 LH DRL Relay Circuit DTC C0695 Position Sensor Overcurrent (8 volt supply)
DTC B0516 Speedometer Signal Circuit Malfunction DTC C0710 Steering Position Signal Malfunction
DTC B0521 Tachometer Signal Circuit Malfunction DTC C0750, C0755, C0760, or C0765 Tire Pressure Sensor Circuit
DTC B0605 BCM Internal Memory Malfunction DTC C1214 Solenoid Valve Relay Contact or Coil Circuit Open
DTC B0846 Battery 2 Out of Range DTC C1217 Pump Motor Relay Contact Circuit Open
DTC B0846 or B0851 Battery Out of Range DTC C1218 Pump Motor Circ Shorted to Volt or Motor Ground Open
DTC B0851 Battery 1 Out of Range DTC C1221-C1235 Wheel Speed Sensor Circuit
DTC B0856 +5 Volt Reference Out of Range DTC C1236 Low System Supply Voltage
DTC B1000 ECU Malfunction DTC C1237 High System Supply Voltage
DTC B1001 Option Configuration Error DTC C1241 MAGNA STEER Circuit Malfunction
DTC B1512-B1537 Driver Information Center (DIC) Switch Circuit DTC C1242 or C1243 Pump Motor Circuit
DTC B1542 Oil Temperature Circuit Short to Ground DTC C1247 Brake Pressure Differential Switch Activated
DTC B1543 Oil Temperature Circuit Open DTC C1248 DRP Disabled
B2187, B2192, or B2197 Power Seat Switch Circuit DTC C1254 Abnormal Shutdown Detected
DTC B2187, B2192, or B2197 Power Seat Switch Circuit DTC C1255 or C1256 ECU Malfunction
DTC B2202-B2208 Window Switch Circuit DTC C1261-C1274 EBCM Internal Solenoid Circuit
DTC B2222-B2224 Mirror Select Switch Circuit DTC C1276, P1644, or P1689 Delivered Torque Circuit
DTC B2226-B2234 Mirror Switch Circuit DTC C1277 or P1571 Powertrain Indicated Traction Control Malfunction
DTC B2236-B2239 Door Lock Switch Circuit DTC C1278 TCS Temporarily Inhibited By PCM
DTC B2242-B2244 Memory Switch Circuit DTC C1281, C1283, or C1286 VSES Sensors Uncorrected
DTC B2252-B2253 Door Key Cylinder Circuit DTC C1282 Yaw Rate Sensor Bias Circuit Malfunction
DTC B2262-B2265 Mirror Position Sensor Signal Circuit DTC C1284 or C1285 Lateral Accelerometer Circuit
DTC B2272-B2273 Mirror Motor Control Circuit DTC C1287 or C1288 Steering Position Sensor Circuit
DTC B2274-B2275 Window Motor Control Circuit DTC C1291 Open Brake Lamp Switch Contacts During Deceleration
DTC B2276-B2277 Door Lock Control Circuit DTC C1292, C1293, or C1296 Master Cylinder Pressure Sensor Circuit
DTC B2278-B2279 Door Switch Control Circuit DTC C1294 Brake Lamp Switch Circuit Always Active
DTC B2282 Battery #1 Circuit DTC C1295 Brake Lamp Switch Circuit Open
DTC B2282-B2285 Battery Supply Voltage Circuit DTC P0101 Mass Air Flow (MAF) Sensor Performance
DTC B2283 Battery #1 Circuit DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency
DTC B2284 Battery #2 Circuit DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Frequency
DTC B2285 Battery #2 Circuit DTC P0106 Manifold Absolute Pressure) Sensor Performance
DTC B2286-B2287 Mirror Position Sensor Circuit DTC P0107 Manifold Absolute Pressure Sensor Circuit Low Volt
DTC B2403 Front Fog Lamp Switch Circuit DTC P0108 Manifold Absolute Pressure Sensor Circuit High Volt
DTC B2408 Rear Fog Lamp Switch Circuit DTC P0112 Intake Air Temp Sensor Circuit Low Voltage
DTC B2482 Backup Lamp Relay Circuit DTC P0113 Intake Air Temp Sensor Circuit High Voltage
DTC B2483 Backup Lamp Relay Circuit DTC P0117 Engine Coolant Temp (ECT) Sensor Circuit Low Voltage
DTC B2527 Horn Relay Circuit DTC P0118 Engine Coolant Temp Sensor Circuit High Voltage
DTC B2528 Horn Relay Circuit DTC P0125 Engine Coolant Temp insufficient for Closed Loop
DTC B2567 Folding Top Release Switch Circuit DTC P0128 Coolant Temp Below Thermostat Regulating Temp
DTC B2573 Hatch Release Switch Circuit DTC P0131 or P0151 HO2S Circuit Low Voltage
DTC B2578 Right Front Turn Signal Monitor Circuit DTC P0132 or P0152 HO2S Circuit High Voltage
DTC B2583 Left Front Turn Signal Monitor Circuit DTC P0133 or P0153 HO2S Slow Response
DTC B2587 Column Lock/Unlock Drive A DTC P0134 or P0154 HO2S Circuit Insufficient Activity
DTC B2588 Column Lock/Unlock Drive A DTC P0135, P0141, P0155, or P0161 HO2S Heater Performance
DTC B2592 Column Lock/Unlock Drive B DTC P0137 or P0157 HO2S Circuit Low Voltage
DTC B2593 Column Lock/Unlock Drive B DTC P0138 or P0158 HO2S Circuit High Voltage
DTC B2597 Traction Control System Switch Circuit DTC P0140 or P0160 HO2S Circuit Insufficient Activity
DTC B2600 Seat Motor to Battery Voltage DTC P0171 or P0174 Fuel Trim System Lean
DTC B2605-B2607 Seat Position Sensor Circuit DTC P0172 or P0175 Fuel Trim System Rich
DTC B2647 Ambient Light Sensor Circuit Low DTC P0200 Injector Control Circuit
DTC B2648 Ambient Light Sensor Circuit High DTC P0218 Transmission Fluid Overtemperature
DTC B2721 PASS-Key Detection Circuit DTC P0230 Fuel Pump Relay Control Circuit
DTC B2722 PASS-Key Detection Circuit DTC P0300 Engine Misfire Detected
DTC P0325 Knock Sensor Module Performance DTC P1134 or P1154 HO2S Transition Time Ratio

DTC P0335 Crankshaft Position (CKP) Sensor Circuit DTC P1220 Throttle Position (TP) Sensor 2 Circuit
DTC P0336 Crankshaft Position (CKP) Sensor Performance DTC P1221 Throttle Position (TP) Sensor 1- 2 Correlation
DTC P0341 Camshaft Position (CMP) Sensor Performance DTC P1258 Engine Coolant Overtemperature - Protection Mode Active
DTC P0342 Camshaft Position (CMP) Sensor Circuit Low Voltage DTC P1275 Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltage DTC P1276 Accelerator Pedal Position (APP) Sensor 1 Performance
DTC P0351-P0358 Ignition Coil Control Circuit DTC P1280 Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P0410 Secondary Air Injection (AIR) System DTC P1281 Accelerator Pedal Position (APP) Sensor 2 Performance
DTC P0418 Secondary Air Injection (AIR) Pump Relay Control Circuit DTC P1285 Accelerator Pedal Position (APP) Sensor 3 Circuit
DTC P0420 or P0430 Catalyst System Low Efficiency DTC P1286 Accelerator Pedal Position (APP) Sensor 3 Performance
DTC P0440 Evaporative Emission (EVAP) System DTC P1336 Crankshaft Position (CKP) System Variation Not Learned
DTC P0442 Evaporative Emission System Small Leak Detected DTC P1380 Misfire Detected - Rough Road Data Not Available
DTC P0443 Evaporative Emission Purge Solenoid Control Circuit DTC P1381 Misfire Detected - No Comm with Brake Control Module
DTC P0446 Evaporative Emission Vent System Performance DTC P1415 or P1416 Secondary Air Injection (AIR) System
DTC P0449 Evaporative Emission Vent Solenoid Control Circuit DTC P1431 Fuel Level Sensor 2 Performance
DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage DTC P1432 Fuel Level Sensor 2 Circuit Low Voltage
DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage DTC P1433 Fuel Level Sensor 2 Circuit High Voltage
DTC P0461 Fuel Level Sensor Performance DTC P1441 Evaporative Emission System Flow During Non-Purge
DTC P0462 Fuel Level Sensor Circuit Low Voltage DTC P1514 Throttle Body Performance
DTC P0463 Fuel Level Sensor Circuit High Voltage DTC P1515 Control Module Throttle Actuator Position Performance
DTC P0480 Cooling Fan Relay 1 Control Circuit DTC P1516 Throttle Module Throttle Actuator Position Performance
DTC P0481 Cooling Fan Relay 2 and 3 Control Circuit DTC P1517 Throttle Module Performance
DTC P0500 Vehicle Speed Sensor (VSS) Circuit DTC P1518 Throttle Module Serial Data Circuit
DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Input DTC P1574 Stoplamp Switch Circuit
DTC P0503 Vehicle Speed Sensor (VSS) Circuit Intermittent DTC P1575 Extended Travel Brake Switch Circuit
DTC P0506 Idle Speed Low DTC P1626 Theft Deterrent Fuel Enable Signal Lost
DTC P0507 Idle Speed High DTC P1630 Theft Deterrent Learn Mode Active
DTC P0522 Engine Oil Pressure (EOP) Sensor Circuit Low Voltage DTC P1631 Theft Deterrent Start Enable Signal Not Correct
DTC P0523 Engine Oil Pressure (EOP) Sensor Circuit High Voltage DTC P1635 5 Volt Reference 1 Circuit
DTC P0530 Air Conditioning Refrigerant Pressure Sensor Circuit DTC P1637 Generator L-Terminal Circuit
DTC P0562 System Voltage Low DTC P1638 Generator F-Terminal Circuit
DTC P0563 System Voltage High DTC P1639 5 Volt Reference 2 Circuit
DTC P0567 Cruise Control Resume Switch Circuit DTC P1652 Powertrain Induced Chassis Pitch Output Circuit
DTC P0568 Cruise Control Set Switch Circuit DTC P1810 TFP Valve Position Switch Circuit
DTC P0571 Cruise Control Brake Switch Circuit DTC P1860 TCC PWM Solenoid Circuit Electrical
DTC P1627, P1680, P1681, or P1683 ECU Malfunction DTC P1870 Transmission Component Slipping
P1627, P1680, P1681, or P1683 ECU Malfunction DTC U1000 and U1255 Class 2 Communication Malfunction
DTC P0608 Vehicle Speed Output Circuit DTC U1001-U1254 Lost Communication with XXX
DTC P0645 Air Conditioning (A/C) Clutch Relay Control Circuit DTC U1300 Class 2 Short to Ground
DTC P0650 Malfunction Indicator Lamp (MIL) Control Circuit DTC U1301 Class 2 Short to Battery
DTC P0654 Engine Speed Output Circuit
DTC P0704 Clutch Switch Circuit
DTC P0706 Trans Range Switch Performance
DTC P0711 TFT Sensor Circuit Range/Performance
DTC P0712 Transmission Fluid Temp (TFT) Sensor Circuit Low Input
DTC P0713 Transmission Fluid Temp (TFT) Sensor Circuit High Input
DTC P0719 Brake Switch Circuit Low Input
DTC P0724 Brake Switch Circuit High Input
DTC P0740 TCC Enable Solenoid Circuit Electrical
DTC P0742 TCC System Stuck On
DTC P0748 Pressure Control Solenoid Circuit Electrical
DTC P0751 1-2 Shift Solenoid Valve Performance
DTC P0752 1-2 Shift Solenoid (SS) Valve Performance - No 2 Or 3 Gear
DTC P0753 1-2 Shift Solenoid Circuit Electrical
DTC P0756 2-3 Shift Solenoid Valve Performance
DTC P0757 2-3 Shift Solenoid (SS) Valve Performance - No 3 Or 4 Gear
DTC P0758 2-3 Shift Solenoid Circuit Electrical
DTC P0785 3-2 Shift Solenoid Circuit Electrical
DTC P0801 Reverse Inhibit Solenoid Control Circuit
DTC P0803 Skip Shift Solenoid Control Circuit
DTC P0804 Skip Shift Lamp Control Circuit
DTC P1111 Intake Air Temp Sensor Circuit Intermittent High Voltage
DTC P1112 Intake Air Temp Sensor Circuit Intermittent Low Voltage
DTC P1114 Engine Coolant Temp Sensor Circuit Intermittent Low Volt
DTC P1115 Engine Coolant Temp Sensor Circuit Intermittent High Volt
DTC P1120 Throttle Position (TP) Sensor 1 Circuit
DTC P1125 Accelerator Pedal Position (APP) System
DTC P1133 or P1153 HO2S Insufficient Switching