generaldave

I have searched different forums and Google and have found people with the opposite problem, but that doesn't help me much.

My buddies and I just did all of the stuff listed in the signature this month (within 10 days). The car ran just fine before.

It runs and idles fine when cold. Once heated up, the idle is up and down, almost to a stall, and the car sputters while driving whether I give it gas or not. It almost stalls out and then juts back in continuously. As far as I can tell it doesn't stop. I haven't driven it far like this though. Also, it is running rich and there is fuel in the oil.

Exhaust setup:
- Pace Setter long tube headers
- Active o2 sensor in driver side Pace Setter bung
- Inactive o2 sensor plugging passenger side hole
- No cats
- No h- or x-pipe
- True dual pipes
- Pipes go into what looks like Thrush style mufflers

The mufflers were lying around a friend's shop. I got them and the piping for $20. We have the piping/mufflers clamped until we can find a welder and come up with a more permanent solution.

Any ideas?

Thank you.
~Dave

Injuneer

Why do you have an "inactive" O2 sensor in the passenger side? The PCM needs an active O2 sensor in each bank of the exhaust, because it fuels each bank of the engine independently. As it is now, it has no way to correct for a rich condition on the passenger side.

Have you scanned it for codes?

Which "engine temp sensor" did you replace - the one in the head for the gauge, or the one in the water pump housing for the PCM?

Have you checked the fuel pressure, both how fast it bleeds down after the pump primes (engine not running), and whether it holds the required pressure at idle, and with the engine under load.

generaldave

It has an inactive o2 sensor on the passenger side because it wasn't there to begin with. I don't see a wire for it either.

I have not scanned it. I found the write up on the paper clip thing though. I will try it out next time I am at the car.

The engine temp sensor is the one in the head for the gauge.

Have not checked fuel pressure.

Thank you.
~Dave

Injuneer

You need to correct the inactive O2 sensor. The 93 sensors are 1-wire, unheated (as opposed to 94 and up 4-wire heated). As a result, if the headers move the sensors further from the engine, they may not get hot enough to work correctly. It isn't unusual for 93 owners with long tubes to convert to heated sensors.

Shoebox has a guide:

http://shbox.com/1/heatedsensor2.jpg

The factory single wire for the passenger side (Bank 2/right) O2 sensor is purple. The wire for Bank 1/left is purple and white. On the 94 and up cars, the passenger side O2 sensor wire is bundled with the knock sensor and starter wires. Don't know if the 93 is the same. With long tubes, your O2 sensor wires will probably need an extension.

Shoebox also has the "flash the codes on the SES light procedure", and a list of LT1 codes. Note that 93 code list is slightly different than 94/95, and is shown in the right hand column of his tables, where different.

http://shbox.com/1/dlc2.jpg

http://shbox.com/1/Dtcs.htm

generaldave

Alright. I will look for the other o2 sensor plug next time too then. If that doesn't help, look into the heated sensors.

Thanks for the help/info so far.

Thank you.
~Dave

generaldave

I found the o2 sensor wire. It has been cut, so I will have to replace the connector anyways. Might as well just go the heated route.

Also, I got the codes:

27 - EGR valve solenoid circuit for 93-95 or QDM circuit/reverse lockout for 93 specific.

12 - ? Doesn't seem to exist.

I checked a couple times to verify 12.

Tomorrow, we are going to try to get the passenger side o2 sensor going, possibly do the heated swap.

Thank you.
~Dave

Injuneer

12 is the "handshake" to tell you it's in diagnostic mode. It's not a trouble code. This is clearly explained in the shbox.com procedure I linked above.

DTC 27 for the quad driver has two possible meanings - reverse lockout if it's a manual trans, TCC lockup signal if it's an auto trans. That is shown in the link I posted. Which trans do you have?

I'm trying to help you. I've been doing this for 17 years. shbox.com is the bible for LT1 tech. You have to use the references I give you, and read the info in the links very carefully. It will save you a lot of confusion.

generaldave

I am using the links you provided. I went through the whole shbox site and printed off the DLC thing so that I can figure out the flashing of the codes. Also, code 12 is not very clear in the printout. It refers to DTC 12 as flash, pause, flash-flash, long pause, flash, pause, flash-flash, long pause, flash, pause, flash-flash, which tells me that the diagnostic system is working.

It also says that codes will be flashed from lowest to highest but it did 27 and then 12.

The car is a 6-speed manual. That is why I only included the manual part of the description from shbox.

I appreciate the help and I am using it. I've done just about everything you have suggested so far.

Edit: I'm retarded. I just realized that flash, pause, flash-flash is 12 and it flashes 12 every cycle too. So it did do 12 then 27.

Thank you.
~Dave

generaldave

I read somewhere that you should read codes with the car hot because some sensors only function when the car is hot. It showed no codes.

Also, someone suggested back pressure or clogged cats. There are no cats, so we removed the mufflers. With open headers, we still have the issue.

What else could this be?

Thank you.
~Dave

Injuneer

You can read codes at any time. Engine does not even have to be running. The SES Light doesn't have to be on. You don't have to read the code while its setting. The code is stored in the computer when it sets. It can be read as an active or stored.

Appears you are running open headers. That would expose the O2 sensors in the collectors to a backwash of air, causing them to read lean, screwing up the A/F ratio. And, did you do a heated O2 sensor conversion when you installed the headers? Sensors could be staying too cool to even work with the 93's single wire unseated sensors.

generaldave

Thanks for the information on the engine codes.

They are open headers as of yesterday. I had mufflers and the pipes ended at about the back seats. We took the mufflers off yesterday because someone suggested clogged cats, which we don't have.

I did not do the heated conversion. Do have the information to do so though, from shbox. What temperature do they have to be to function properly? I see a generic Google search popped up with 300C/572F, not necessarily specific to the 93 Camaro though.

My dad has an infrared temp gun. Thinking about using that to see the temp differences between the headers at the engine and the other end of the headers. Seems like the next step is to do the conversion regardless.

Thank you.
~Dave

Injuneer

600*F in round numbers.

generaldave

So it was about close. Thank you.

I should be able to get to both of these Monday. At this point, I'm mostly just curious the temperature difference. I know the conversion needs to be done regardless. I'll let you know how it goes.

Thank you.
~Dave

Injuneer

You need to run a data log usng Scan9495 (works on 93 also). That will show you if the O2 sensors are working, if the ECM is in closed loop, whether the LTFT's are way off, etc.See the sticky thread on the "Computer Diagnostics....." forum.

Pullngz

generaldave, you said the car ran fine before the mods, in your first post.

Before you put the headers on, did you have the stock manifolds/y pipe/cats?

Did it only have 1 o2 sensor(driver side)hooked up, and the passenger side was not hooked up electrically?

I can't see how it would run fine, if the above statement is true. Missing input from the passenger side O2, but I will take your word for it.

If all the above is true, and you are now sputtering when hot, after only changing headers. I would be looking for exhaust leaks, causing a rich condition. Burnt plug wires, mine as well pull some plugs, and check their condtion as well.

As Fred said, a scan of the computer, is essential to find out if the sensors are functioning properly.