Mark Hawkins

What are the two sensors for that are located on top of the water thermostat? The one on the passenger side has two black connectors on them however noting is connected to them. Was this part of the smog stuff ? (smog stuff has been removed) The other sensor has a tube coming from the carb and another tube is coming into the sensor however I don't know its origin. 2nd) what tool do I use to read the codes? I found the device under the ashtray however I'm lost from there. What is suppose to flash, the Check Engine light? Thanks a bunch in advance.

nate99

Nevermind, I was wrong...

Tim81

The sensor with the two black caps was for the EGR and the heat riser, the other sensor with the vac line coming from the carb is for the purge line on the charcoal canister. To check you ecm codes turn on the ignition switch but don't start the car, using a flat blade screw driver short the two terminals together on the far left of the conector you found under the ash tray. The check engine lamp will flash a series of codes, the first should be one long flash followed by two short flashes this equals a code 12 which mean the system is working correctly, if there are any other codes stored in the computor after code 12 the check engine lamp will flash those codes after the code 12 flashes three times. Each additional code will flash three time before moving on to the next code stored. When all the codes have been flashed the system will start over again with a code 12. Hope this is helpful...Tim

damoroso

The one on the thermostat housing is the TVS switch (the 2nd one you describe), which helps control the evaporative canister. The other is a vacuum switch for the EGR system. To read codes, you can jumper the connector (the last two wires on the right side of the connector (mine is under the ashtray)) and the Check Engine light will flash the codes for you, assuming the light is working. It sounds like you want to get the systems working correctly, if so, I'd suggest getting a service manual, it'll walk you through the codes and associated troubleshooting.

Tim81

Mine might be installed backwards, look for the two terminals that don't have a divider between them. Either on the right or left of the connector. Damoroso is correct without a manual it will be very hard to trouble shoot.

Mark Hawkins

Thanks so much guys. I just got the Haynes Repair Manuel, however from what I've been reading, a service manuel may be better. The evaporative canister, what's it's purpose? Do these go bad? Do you need to change this thing?

Mark Hawkins

Okay, the codes I got were 13,15,23 & 44. I plan on having the carb rebuilt, which company(s) should I advoid and who should I contact for quotes? I was looking to send the one that is on the car to have rebuilt instead of giving mine as a core charge. Any suggestions? Thanks again.

qwank

on an 81 the one on the right side is for AIR pump and heat riser. the one on the left side goes to the canister purge.

damoroso

Get a service manual and you can rebuild the carb yourself. The Haynes manual is okay, but the GM sercive manual (you can get them from any vette parts supplier) is more accurate and better IMHO. There are several companies out there who will do the carb for you, my choice is Cliffs High Performance. He's really good (which is why he has such a backlog of work) and knows exactly what he's doing. Plan on spending several hundred dollars for a rebuild, and about $75 if you do it yourself. A rebuilt carb is close to $500 off the shelf...

Mark Hawkins

thanks damoroso and qwank.

Easy Mike

Much better. The Haynes is handy every now and then and useless at other times.

The GM chassis service manual and the assembly instruction manual (AIM) would be of much more help to you. Order both.

Order a reproduction owner's manual if you do not have an original.

7t9l82

make sure the throttle shafts aren't sloppy if you do it yourself. cliffs would be good.

gbvette62

The canister is how/where the fumes from the gas tank vent. Do they go bad, maybe but I wouldn't really expect you to need to replace it.

The GM Corvette Service Manual is far superior to the Haynes, Chilton, or other similar manuals. They are the same manual that Chevrolet dealer mechanics used.

Your codes are:

#13 Oxygen Coolant Circuit
#15 Coolant Sensor Circuit (High)
#23 ??????
#44 Lean Exhaust System

I don't show a code 23, there is a code 22 & 24. Code 22 is TPS Circuit (Low V), and 24 is Vehicle Speed Sensor Circuit.

Rawj

Code 13: Oxygen sensor circuit
15: Open coolant sensor circuit
23: Mixture control solenoid circuit
44: Oxygen sensor lean

Mark Hawkins

good deal. Thanks. I'll look for the GM Corvette service manual.