We installed a cc-306 with new timing set, springs and a tune. We fired it up and let it run at 2k rpm for about ten minutes. No issues. Plenty of oil pressure, 42 psi of fuel no heating problems. Trouble is that the engine will "hunt for a idle between 600 and 900 rpm and when you touch the throttle there is no response like its out of fuel. If you slowly apply throttle the engine will climb to about 2500 then shutter like its on a rev limiter. wtf did we do wrong? I'm sure we must have missed something, but right now am at a loss

 

What is the target idle set at in the tune?

Noted the "open long tubes"..... Do you run a closed loop tune? If so, did you do the heated O2 sensor conversion? Are the O2 sensors in the collectors, exposed to a backwash of air at low engine loads?

 

The tuner did set the tune up for closed loop operation. Funny you mentioned that tho. My buddy who helped out did plug the sensors back up after we were finished everything. I didn't think it mattered if the system runs closed loop. Think that could be a problem? Also, they are not the heated type o2 sensor.

 

Additionally, I do not know the target RPM at this point. Honestly, I didn't think to ask about any of the tune parameters. I will be contacting them tomorrow to ask about the tune. It is the same company who did the initial EPROM tune for me last year and it worked great! Is there any more information fro the tuner that I should request to help figure this out?

 

A 306 is going to have a lot of overlap, and you're going to get a lot of unburned fuel and air in the exhaust at low RPM. May not be hot enough to get the O2 sensors hot enough to work.

When the O2 sensors do get hot enough to work, O2 sensors see the air, ECM thinks it's running lean, and adds fuel the engine doesn't need. Add the backwash of air into the collectors at low engine loads, and it's probably going to run very rich.

You can scan the 93 ECM with Scan9495 (93 capability was added after he named it). That would tell you things like the target idle speed, whether the coolant temp sensor was providing good info, ditto on the MAP and IAT sensors, which are critical to the 93's speed-density system. Will tell you if it's going into closed loop, and how the O2 sensors are reacting, and whether the ECM is adding excess fuel.

https://www.camaroz28.com/forums/com...95-lt1-874306/

Did you scan the ECM for codes.... maybe you forget to hook up a sensor, or the wiring is damaged?

 

After you check for codes and if there is none..

Everything is suspect..

Can you pull chip and go back to stock tune??

Fuel pump relay. I had a weird experience with mine ...smacked and it worked lol

Plug wires. 6 and 8 and 5 and 7 always seem to get mixed up well atleast for me lol..

Last is opti but I couldn't rev past 1k

I'm not as experienced as most here but these were my experiences a week ago with my 93...

Art

 

I have checked and recheck to make sure all sensors were hooked up, not to say I haven't overlooked one. I will try to unplug the o2s' and double check the wiring and plug wires again. I do have the ability to put the stock tune back by unplugging the piggy back chip. I can try that to see if it affects any change. Lastly, I will try my best to log some data with the datamaster program I have. Thank you all for your help and suggestions. Hopefully my next post will be good news.

 

Did you scan it for codes?

 

No I did not. Yesterday I was unable to find time to head to the garage where I keep the car. I did download the program you recomended and ordered the usb cable required to make it work. Hopefully today after work I can get down there and see what codes, if any, are stored

 

DataMaster pulls codes.

 

For whatever reason I could not get the car to go into diagnoses mode. I jumped pins a and b together (top row right hand corner) on the ALDL plug with a copper wire, but the "service engine soon" light never flashed one slow and two fast indicating it was in diagnoses mode. I have used this method before with success. I checked all the fuses inside the car and none were blown.

 

Does the SES light come on briefly when you turn the key to "on", confirming that the light is working?

 

The SES light stays on. It never flashes when I install the jumper

 

And you are doing it exactly as shown:

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

 

yes. That is actually the same picture I have.