Trying to do a little diagnostic scanning on my '94 Z, but Free Scan is giving me some fits. It's doing exactly what Tuner Pro RT was doing, collecting engine data but not displaying any trouble codes. I've made sure the COM ports match both on my laptop and on Free Scan, I selected the "Interact" radial button and hit "Force Data" on the main screen, and I have the correct vehicle selected in Free Scan also. I know I should at least be displaying one trouble code for my inoperable AIR pump. Does anyone have any ideas of what I'm potentially missing or doing wrong? Any help would be greatly appreciated.

Thanks

 

Maybe you don't have any code set. On a '94 the air pump DTC is set if the PCM does not see +12v going to the air pump from the air pump relay in the under hood panel. Unless yo have removed the air pump fuse and or relay you will not throw a DTC even w/o an air pump attached. Try pulling the relay and you should see a DTC after a cold start when the PCM commands the pump on.

 

Gotcha. Thanks for the info on that, Bob. What I'm really trying to diagnose is nt fuel issue I think I have. I'm leaning toward my o2 sensors because every time the car gets into closed loop, it just wants to bog down and die. I've changed the plugs, wires, coil, fuel filter, fuel pump, and pcv valve. None of those corrected the problem. Any ideas anyone?

 

Tuesday morning bump, any ideas anyone?

 

Since you have the cables and the PC download TTS Datamaster EE it's good for 20 free logs up front then you have to buy the license. It will show up any defective O2 or obvious sensor problems w/o having to throw money at parts that may not need replacement. You can post the data logs on a file sharing site and we can take a look at them for you. Bogging is usually fueling (which you replaced FP and filter), have you verified fuel pressure is 38-43 lbs under load ?? Or ignition ICM, Coil or High voltage distribution, plugs. Rarely can be caused by exhaust restriction (plugged cat) .