although I am an electronic tech, this is my first corvette, the other day while coming home from work I starting losing speed and eventually it kept dieing and wouldn't go much over 4 or 5 mph. Any suggestions?

 

That's what mine did when it needed a fuel pump. I lost psi. It's supposed to be around 40 to 45 psi from what I gather. That's what I would check first. This explanation is probably over simplified but replacing the fuel pump cured my problem.

 

replaced fuel pump this morning, didn't help, i did notice that one exhaust has black smoke coming out of it and the other is sucking in air, I did find one spark plug wire loose, but still no go, every time you push on the excelator it kills the engine or slows down even more.

 

Has the car been running bad before this happened? Whay year is it? Older tuned port f/p is 35 - 45, usually operates aaround 35. Sounds like a converter is stopped up. If you pull your O2 sensors out and run it, does it run better? If you have a vacuum gauge, install it on a manifold vacuum source, start engine (with O2's back in), take note of vacuum reading at idle, throttle up to 2000 rpm and hold, reading should return to original reading @ idle or close. If you have very low vacuum, then you probably have an exhaust restriction. [8D]

 

mech 259 we did crawl under the car and the converter has a hole in it, past the converter its straight pipe out, no muffler.

 

What year is the car? 86 and some later, not sure of range, had preconverters, like mine and both were bad. I just cut them out and put pipes in. Post your vacuum readings if you can.

 

check the fuel pump relay. the oil pressure switch and the ecm energize the pump relay during operation. if the relay fails, there is still a "limp home mode" that can bypass the relay if it fails. its possible that is what is occuring.

I hesitate to think that plugged cats would have such a sudden impact on your car. I would think that would be more of a gradual deterioration.

 

looking at the electrical diagram it seems that the fuel pump connects directly to the ecm, Since the catalytic convertor has a big whole in it, and the right side tail pipe is sucking air, I think I'll try the obvious first. The one thing I learned in troubleshooting electronics was always fix the obvious problems, then move on.

 

ECM controls the relay that controls pump. Relay is energized when the ECM sees an ignition signal. The oil pressure switch under the distributor is redundant for a backup in case relay fails. Pump is working if your car starts and pressure is good. Check your engine vacuum at idle then at 2000 rpm. Should be close to same, if not you have an exhaust restriction. Also, check condition of spark. Should have a bright blue spark, not dim and yellow. If dim, you might have a coil going out.

 

I have ordered a new catalytic converter, seems like the likely culprit since, the left exhaust is putting out and the right one is sucking air, with the big hole in the converter, my guess is that the ecm is in the protection mode.