96LT1Z

Alright so I posted earlier this week with my other thread that the camaro isn't running right. But last night it really wasn't running right, from idle to about 2300rpm it is almost like it's chugging, just isn't running smooth at all. When you stand behind the car it doesn't sound as smooth as it normally does. Also the exhaust didn't smell right, almost smelled rotten, but it has LTs and off road y, so it doesn't have bad cats.
So this morning I started it up and just as it was last night. It doesn't sound right. I popped the hood and the motor sounds good, I revved it a couple times and sounded ok, when I went behind the car it looked like my care coughed up a lung on the concrete. Also I am getting absolutely horrible mpg on this tank. So undoubtedly it is running rich.
I have two places to start to look, the throttle body coolant bypass and bad header gaskets. Other thank that i don't know where to look.

ahritchie

iTrader: (1)

Scan the PCM if you coolant temp sensor is reading -40....if so, it's gone bad and does make the car run very rich and get terrible MPG. If it reads accurate, I'd do a bit of diagnostics to check the MAF and O2 sensors next. A PCM scan may reveal the issue pretty easy if you're lucky. You would almost certainly be smelling it if the header gasket is leaking that bad.

http://shbox.com/1/4th_gen_tech2.html#ect

96LT1Z

Is that the sensor on the radiator? Or on the drivers side?

ahritchie

iTrader: (1)

Nope (I see you didn't thoroughly read the link I posted) ...the one on the radiator is the low coolant sensor, the sensor the PCM uses is on the waterpump. Autozone may be able to scan the PCM for free, or the Chevy dealership certainly can, but will probably charge $40 or so to scan it unless you make friends with a service manager (highly recommended), SCAN IT first! Don't just start throwing parts at it just yet

96LT1Z

Alright so I went and had the codes pulled at the dealership, they said it would cost me $100 for just some diagnostics so I just pulled the codes.
Here's what I got:
P0443 EVAP PURGE VALVE
P0140 O2 NO ACTIVITY BANK 1 SENSOR 2
P0400 EXHAUST GAS RECULATION
P0161 O2 HEATER CIRCUIT BANK 2 SENSOR 2
P0160 O2 NO ACTIVITY BANK 2 SENSOR 2
P0154 O2 NO ACTIVITY BANK 2 SENSOR 1
P0141 O2 HEATER CIRCUIT BANK 1 SENSOR 2
P0403 EXHAUST GAS RECIRCULATION CONTROL

96LT1Z

P0154 O2 NO ACTIVITY BANK 2 SENSOR 1

I think this is the only one that matters too me, because everything is either blocked off or removed (evap, egr, rear o2s)

96LT1Z

Alright im done. The car is backfiring like hell. I am going to wait till the end of this week when it warms up a bit to look at it more

KyleW707

Are you having hard start issues once the car reaches operating temp? o2's are only used once the car reaches temp and goes into closed loop, so if its doing this all the time, I'm not putting money on the o2 sensors. My coolant temp sensor was bad and it was running like sh*t, everything you explained, plus nearly stalling at lights, misfiring especially at high rpm, my mpg was about 7-9. It also threw like 22 codes, replaced the temp sensor for about 20 bucks and all was better, no more codes either. If you do decide to try the temp sensor, be quick with it, have the new one outta the box and ready to go in, because coolant will come out of the water pump, also do this preferably when the car is cold, so the coolant isnt hot. Try to cover the opti with something so it doesn't get wet. Also, I'd recommend hand tightening as much as possible, and then a wrench to snug it up, they break fairly easily when using a socket.

96LT1Z

Alright I'm working on the car. Bank 2 sensor 1 is the o2 my codes say is bad. I pulled it out its real black. And there looks to be some moister or oil of some kind in the connector. Now unless that moister in the connector is really messing with it, why would it read, no activity?

ahritchie

iTrader: (1)

Yes, oil/moisture will mess with the O2 sensors....When I had a RMS oil leak it got oil all over the O2's and both had to be replaced to read properly; PCM for less could not finish dyno tuning mine till I got the oil leak and O2's replaced. Get some AC delco ones and figure out where the oil is coming from....possibly the dreaded back of the intake leak? A LT1 classic

Ed Wright

iTrader: (1)

The O2 sensors showing no activity are likely the issue. If the long term fuel trims are big numbers positive values, it will effect it soon as you start it. Does not have to go into closed loop first. Your spark plugs are likely sooty black also.
You need somebody competent (Too many guys that have scan tools don't know what they are looking for or at.) with a scan tool check it for you. A decent scan tool can reset the fuel trims, that will help initial start up if they are something like +25%. The PCM will eventually put them there again after it runs a while with the problem not fixed. You need to change the oil after it's fixed also. Gasoline vapors in the oil, due to the PCV, screw with your fuel trims also.
Hope this helped.

Alex94TAGT

Water in the connector could certainly cause the oxygen sensor data signal to get short circuited / report no activity. That could also have blown the fuse for the oxygen sensors' heater circuit -- check that as well (I believe the OBD2 cars have a specific engine sensor fuse).

Clean out the connectors with electronics parts cleaner, reset the PCM and see what happens. Still shooting in the dark without scanner data, but this is virtually free to check.

96LT1Z

So I pulled the vacuum line off of the fuel pressure regulator and it smelled of gasoline and drop of gas came out. So it needs a fuel pressure regulator. So I will check and see if there is indeed an oil leak, but I am pretty sure it is just some left over dielectric grease in the connector

Ed Wright

iTrader: (1)

That is your rich problem.

96LT1Z

OK so what fuel pressure regulator should I get?
I can get a Delphi, or an AC DELCO
I know they are supposedly the same. But the Ac Delco is like $120, and the Delphi is like $75.
Why the price difference? What should I get?????

ahritchie

iTrader: (1)

I wouldn't be concerned running the Delphi one....BTW, you can find one considerably cheaper than that....(under $40 at partsgeek.com). Delphi is just a huge automotive parts manufacturer who has a joint venture with GM (partners), AC delco, is "Official" GM parts. The reason for the price difference....GM likes to stick it to you especially if you get parts at a dealership, more $$ for them!

bfd811

My car has the same problem except its showing no activity on bank 1 not bank 2. I believe my drivers o2 sensor has 190k on it in which it should probably be replaced anyway. My car still needs to be tuned @ idle, its had a WOT tune but we couldn't do idle because I had open headers on the car at the time, I think the rich condition might have killed the sensor. Keep us updated and let us know what you find and Ill do the same, Ill probably mess with it sometime tomorrow.

96LT1Z

I can't upload a pic off my phone, but last night I pulled plugs and the bad header gaskets. The pass. Side plugs are the blackest I have ever seen a spark plug. Ever.
The pass. Side is the side with the dead o2. And then my header gasket was also torched. And they are Percy's aluminum ones...,, I don't know what happened to them

96ssindeed

Personally if it was me id do a really good tune up if you have the money. New plugs, o2 sensors, and change the temp sensor and fuel regulator. That's just me though.

96ssindeed

Also, did you delete the egr stuff? Ever get it tuned out?