My friend just installed the TSP headers on his 04 Z16. Now its barely running after 200 miles. My guess is that the rear O2 sensors need to be bypassed or shut off. I just ordered the O2 sims. I didn't get to check the DIC for the codes yet. But I am anticipating O2 errors. What else is there? Am I missing anything? AIR or EGR? Any info is greatly appreciated. Thanks, Frank

 

I doubt its the rear O2's, those are just for emissions. It 'might' be the front o2 if they were damaged or you got anti-seize on them. They tell the ECU how much fuel to add/subtract (fuel trim).

Maybe if you can give a little more detail as to what you mean by "Now its barely running after 200 miles." Does it idle rough, is it missing at all?

 

The most often cause of problems after header installs is people not putting the plug wires on all the way. Check those out carefully.

 

I'll know more when I get to hear it run and check out the codes. From what I was told, the idle is very rough and it's running very rich. I'll check the plug wires also.

 

my guess would be that your buddy installed the fron O2 sensors backwards. This would cause the pcm to eventually confuse the hell out of itself and throw the a/f ratios way way wayyy off since its compensating based on O2 feedback which is backwards. IF it gradually got worse after more miles were put on the car I would check this 1st.

also checked for burnt or damaged front O2 sensors/wires/plugs that may be touching the headers themselves. but even if this were the case the car would just throw a code about an 02 sensor then go into Open Loop mode and still drive fine.

also if the car was not tuned for the headers the car is most likely going into COT (cat overtemp) mode and dumping way too much fuel thinking the missing cats have overheated.

did he use hte correct header flange gaskets??? exhaust manifold gaskets from a 99 C5 are the CORRECT ones to use with TSP headers.


When I installed my TSP headers on my 01 Z06 I made sure the front O2 sensors were installed on the correct sides, the wires were tucked away from the headers nice and neat and secured VERY good so they wont ever fall and contact the headers and get burnt. I tuned the rears out with LS1edit and turned off COT and disabled the rear 02 tests as well. I started my Z up with absolutely no issues and 6000 miles later its still running strong.

 

Dude, I just had the same exact thing happen to me. Had it to 2 shops and neither could figure it out. Finally took it to the Vette Doctors and apparantly they guy criss-crossed the 02's, but he's not sure thats all it is, as Carmen only had time to look at it briefly. But the car ran perfectly before that so I am sure it was probably just that or something simple like that. I have another thread on this and I will post back with my results.

 

Being as plugs and O2s are the only things you really mess with on an install, it's one of them! Don't worry yet.

 

Ahh, you guys beat me to it. I was going to guess that he got the left and right O2s backwards too. It would be easy to make that mistake. But I disagree that the gaskets could have anything to do with it unless you had a gigantic leak. And I have put a couple thousand miles on my TSPs on my '01 Z06 with no tune. COT is not a problem. It runs fine and I am still getting over 26 mpg, so I know it's not running extra rich. I am also running with my AIR pump still on the car and plugged in but not connected to the exhaust. The car has a check engine code for that right now, but it does not seem to be affecting the way the engine runs.

 

how would switching the left & right sensors mess anything up? The pre cat 02's are the same for L & R side aren't they.
is the harness for the front 02's even long enough to let you plug it into the opposit side?

 

Is there a reference as to which side is L or R? Wire colors?

 

#4 plug wire was off. O2 sims are going on tomorrow also.

 

That would do it.

 

You have to get harness extensions to reach the new O2 sensor locations on the headers, so yes they are long enouph. And while you could switch the sensors themselves, if you plugged the sensor in the left header into the right engine bank harness and vise versa, the PCM would make fuel trim adjustments to the right side of the motor for what it reads coming from the left. Then since it's ajdustment did nothing, it would adjust more and more. It would get all out of wack. And it would be easy to make this mistake because the two O2 sensors cross each other with these headers so it looks like you are plugging them in backwards when you are doing it correctly.

 

Just one cylinder not firing would make it "barely running?" I have never done it on this engine, but other V8's run okay on seven.

 

Glad you got it figured out. Reversing the front o2 sensors will cause it to run real bad as well. You can probably guess how I know.

 

OK. I give up.... How? jk. Thanks for all the info guys.

 

Score

 

O2 sims do not fit 04Zs. Got them from Speed Inc. It never ends...

 

Yeah anytime you change anything from stock you just have to make sure you have all your info correct down to every detail to make sure its done right. A lot of people talk/act like you just throw the part in there, but I always find out theres more to it than that, and there's often stupid little details like this that are missed. I even had to go through a lot of confusion with getting the right GM gaskets b/c you actually use a different part number than the original OEM part #.

And my car was down for 3 weeks after LT install. Turns out the 02's were criss crossed

 

Ive got the same deal as you, I just disconnected the rear o2's and the air system isn't hooked up either, car runs fine and still getting great mileage.