I put headers on mycar and haven't blocked off the EGR, the car runs like **** is that why? should I cover them up and see what happens?

 

They are uncapped and blowing exhaust into the engine bay???? Hell yeah cap em or hook up the AIR hoses at least, I don't think it'll make you car run like poop though but it may burn a hole through something and I'm sure it sounds like Poop!

Check O2 sensor wires to make sure they aren't crossed and also make sure the Ground strp on the Driver's side of the block is reinstalled, those are the two most common problems. A few have forgotten to hook up the PCV vaccume line too...

 

I don't believe I crossed the O2 because wiring them was a BITCH the driver side header leans the o2 towards the passenger side and you have to go back over the header to run the O2 right?

 

What codes are showing?

 

P0300 (C) Which is random misfire....... I ordered plugs and wires I only PRAY they come in today

 

I talked to ECS they think I may have cracked a plug I ordered plugs but I may go get some cheap plugs just to rule it out

 

First of all, the AIR(not EGR) ports need to be blocked off. You can't have them open. At idle, you'll most likely get pressure from the ports, and with throttle input, it will draw air into the exhaust stream....and may ignite. Cap them off immediately.

A cracked plug is common during a header install Hopefully you have pulled the plugs for inspection.......there is no need to guess here.

I'm not sure what you mean by "back over the header", with regards to the O2's. The fronts connect left to left, right to right. The rears cross, i.e. the harness for the left rear O2 runs down the right side of the tunnel, and the harness for the right rear O2 runs down the left side of the tunnel.

Finally, if you have O2 wiring run over the headers, it may be heat damaged....inspect it.

 

Found out the one injector is bad I am going to replace em tomorrow and hope that fixes the problem

 

Not sure how you verified the injector but I had a similar problem with another car and it turned out to be the quad driver in the PCM that was the issue (it wasn't providing the signal to fire the injector).

 

do you remember the code for that? and how did you diagnose/fix the problem?

 

In all fairness, this would represent the least likely failure......wouldn't you agree?

 

How are you reading the DTCs??

Like this?

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.

You can read the DTCs while the engine is running. If you turn the engine OFF and then back ON, that can clear some DTCs that may be important with identifying a problem. One example is a Misfire DTC (p-0300) If the engine is shut down, the DTC will clear.

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!!

 

Less likely but some folks just throw in injectors without verifying they are received signal. Best to check both before deciding on what to buy.

 

I don't see how you can screw up a injector putting headers on. If you didn't remove the plugs when you changed out the exhaust manifold my bet is a cracked/broken spark plug. If you don't plug the AIR port on the headers you will gas yourself and probably burn two holes through your hood!